In the AVI the displays seem very bright to me... :cool:
There are no current limiting resistors on the board or in the schematic. 5 V should not be a problem once the program is OK as then each digit should only on for max 1/8 of the time, a segment even less, but while you are testing the program it would probably be safer to use 3.3 V and even then make sure that a display is not on for too long or it might burn out.
I do not speak Spin, but in a BS2 my trial program would look like this;
' 2x4 7 segment display using 74HC595 shift register
'
' http://forums.parallax.com/showthread.php/157074-7-Segement-DisplayHelp-Needed
'
' {$STAMP BS2sx}
' {$PBASIC 2.5}
'
DIOpin PIN 0 ' DS (Data Serial)
CLKpin PIN 1 ' SHCP (Shift Clock Pulse)
LATCHpin PIN 2 ' STCP (Storage Clock Pulse)
'
' digits: 12345678 2x4 digits Common Anode 7 segment display
digit1 CON %10000000 ' digit 1 high = on, others low = off
digit2 CON %01000000 ' digit 2 on
digit3 CON %00100000 ' digit 3 on
digit4 CON %00010000 ' digit 4 on
digit5 CON %00001000 ' digit 5 on
digit6 CON %00000100 ' digit 6 on
digit7 CON %00000010 ' digit 7 on
digit8 CON %00000001 ' digit 8 on
'
' segments:
' --a--
' | |
' f b
' | |
' --g--
' | |
' e c
' | |
' --d-- .dp
'
' abcdefgp
zero CON %00000011 ' segments abcdef low = '0'
one CON %10011111 ' segments bc low = '1'
two CON %00100101 ' segments abged low = '2'
three CON %01100001 ' segments afged low = '3'
four CON %10011001 ' segments fbgc low = '4'
five CON %01001001 ' segments afgcd low = '5'
six CON %01000001 ' segments afgcde low = '6' (with flag)
seven CON %00011111 ' segments abc low = '7'
eight CON %00000011 ' segments abcdef low = '8'
nine CON %00001001 ' segments abcdfg low = '9' (with flag)
dp CON %11111110 ' segment dp low = '.'
digitdata VAR Byte
segmentdata VAR Byte
'
' =========================[ main ]================================
LOW LATCHpin ' initialise latch
DO
digitdata = digit1 ' set digit to light up
segmentdata = one ' set segments to light up
SHIFTOUT DIOpin, CLKpin, LSBFIRST, [segmentdata, digitdata] ' shift out data, show '1' on digit 1
PULSOUT LATCHpin, 1 ' make data visible
SHIFTOUT DIOpin, CLKpin, LSBFIRST, [two, digit2] ' shift out data directly, show '2' on digit 2
PULSOUT LATCHpin, 1 ' make data visible
SHIFTOUT DIOpin, CLKpin, LSBFIRST, [three, digit3] ' continue for all 8 digits, show '3' on digit 3
PULSOUT LATCHpin, 1
SHIFTOUT DIOpin, CLKpin, LSBFIRST, [four, digit4] ' show '4' on digit 4
PULSOUT LATCHpin, 1
SHIFTOUT DIOpin, CLKpin, LSBFIRST, [five, digit5] ' etc.
PULSOUT LATCHpin, 1
SHIFTOUT DIOpin, CLKpin, LSBFIRST, [six, digit6]
PULSOUT LATCHpin, 1
SHIFTOUT DIOpin, CLKpin, LSBFIRST, [seven, digit7]
PULSOUT LATCHpin, 1
SHIFTOUT DIOpin, CLKpin, LSBFIRST, [eight, digit8]
PULSOUT LATCHpin, 1
SHIFTOUT DIOpin, CLKpin, LSBFIRST, [dp, digit8] ' show decimal point on digit 8
PULSOUT LATCHpin, 1
LOOP 'forever
' ==================================================================================
I will test it when I get home Thursday night. In the meantime I would suggest an ohmmeter or continuity tester to determine what pins are connected together. The '595 and display pinouts are known so it should only take 10 minutes or so to do that. Probably a lot easier than mucking around with untested programs.
Results of Duane's code. I will try kwinn's on Wednesday.
I don't suppose you tried adding the "!activeBits" line?
Here's essentially the same thing as the earlier code but with the anodes and cathodes reversed.
CON
_clkmode = xtal1 + pll16x
_xinfreq = 5_000_000
'' Pin Assignments
SHIFT_REGISTER_DATA = 0
SHIFT_REGISTER_CLOCK = 1
SHIFT_REGISTER_LATCH = 2
DIGITS = 8
MAX_DIGIT_INDEX = DIGITS - 1
MAX_DISPLAYABLE = 99_999_999
HIGH_DIGIT_DIVIDER = 10_000_000
SEGMENTS = 8
MAX_SEGMENT_INDEX = SEGMENTS - 1
BITS_TO_SHIFT = SEGMENTS + DIGITS
MAX_BIT_INDEX = BITS_TO_SHIFT - 1
SEGMENT_A = 1 << 7
SEGMENT_B = 1 << 6
SEGMENT_C = 1 << 5
SEGMENT_D = 1 << 4
SEGMENT_E = 1 << 3
SEGMENT_F = 1 << 2
SEGMENT_G = 1 << 1
SEGMENT_DP = 1 << 0
COMMON_ANODE = true '' set to false if digits are common cathode
VAR
long shiftStack[64]
long fourDigitNumber
long shortInterval, longInterval
byte digitBits[DIGITS]
PUB Setup
'' This method starts in cog #0
'' This method starts one additional cog.
'' Presently there are six unused cogs.
shortInterval := clkfreq / 2
longInterval := clkfreq * 4
cognew(MaintainDigits, @shiftStack)
MainLoop
PUB MainLoop | digit, activeBits
repeat
repeat fourDigitNumber from 0 to MAX_DISPLAYABLE
waitcnt(longInterval + cnt)
PUB MaintainDigits | previousFourDigitNumber
'' This method runs in its own cog. It will continuously
'' display the value of "fourDigitNumber" on the 7-segment display.
dira[SHIFT_REGISTER_DATA] := 1 ' direction settings need to be done within cog using the pins
dira[SHIFT_REGISTER_CLOCK] := 1
dira[SHIFT_REGISTER_LATCH] := 1
previousFourDigitNumber := $7FFFFFFF ' some impossible number
repeat
if fourDigitNumber <> previousFourDigitNumber ' check to see if it's a new number
previousFourDigitNumber := fourDigitNumber
BustDigits(fourDigitNumber)
repeat result from 0 to MAX_DIGIT_INDEX ' result is used as a temporary variable
ShiftOutDigits(result, digitBits[result])
waitcnt(shortInterval + cnt) ' This line should be commented out or delay made very short
' once the program is working.
PUB BustDigits(numberToDisplay) | divisor
'' Convert a number to bits representing the segments
'' to light in a 7-segment display.
numberToDisplay <#= MAX_DISPLAYABLE
divisor := HIGH_DIGIT_DIVIDER
repeat result from 0 to MAX_DIGIT_INDEX
digitBits[result] := bitsInNumber[numberToDisplay / divisor]
numberToDisplay //= divisor
divisor /= 10
PUB ShiftOutDigits(digit, activeBits)
'' This methos moves the digit bit to the correct location and
'' combines the digit and segments bit together.
'' The combined bits are shifted out.
'' This method only displays a single digit at a time.
'' All 8 digits need to be cycled quickly to make them
'' all appear to be on.
case digit ' convert digit to bit position
0..3: ' according to schematic what we call 0 - 3, they call 4 - 7
digit := 11 - digit ' range 11 - 8
4..7:
digit := 19 - digit ' range 15 - 12
other:
return
'' our numbering system 0 1 2 3 4 5 6 7
'' the displays system 4 5 6 7 0 1 2 3
digit := 1 << digit ' set the digit bit high
!digit ' invert the bits (only the digit bit will be low)
digit &= $FF00 ' only keep top 8 bits
activeBits &= $FF ' only keep bottom 8 bits
activeBits |= digit ' "Or" the bits controlling the digits together with the
' bits controlling the segments.
' The top 8 bits control the digits and the bottom 8 bits
' control the segments.
if COMMON_ANODE '' set this to false in CON section if it's a common cathode display
!activeBits ' invert bits
repeat BITS_TO_SHIFT
outa[SHIFT_REGISTER_DATA] := activeBits
outa[SHIFT_REGISTER_CLOCK] := 1
outa[SHIFT_REGISTER_CLOCK] := 0
activeBits >>= 1
outa[SHIFT_REGISTER_LATCH] := 1
outa[SHIFT_REGISTER_LATCH] := 0
DAT
bitsInNumber byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_E | SEGMENT_F '0
byte SEGMENT_B | SEGMENT_C '1
byte SEGMENT_A | SEGMENT_B | SEGMENT_D | SEGMENT_E | SEGMENT_G '2
byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_G '3
byte SEGMENT_B | SEGMENT_C | SEGMENT_F | SEGMENT_G '4
byte SEGMENT_A | SEGMENT_C | SEGMENT_D | SEGMENT_F | SEGMENT_G '5
byte SEGMENT_A | SEGMENT_C | SEGMENT_D | SEGMENT_E | SEGMENT_F | SEGMENT_G '6
byte SEGMENT_A | SEGMENT_B | SEGMENT_C '7
byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_E | SEGMENT_F | SEGMENT_G '8
byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_F | SEGMENT_G '9
I added a quarter of a second delay while each digit is displayed. You'll want to take this delay out (or shorten it) once you get a working program but the delay will help diagnose what's going on.
I also added a constant "COMMON_ANODE" which can be set to true or false.
COMMON_ANODE = true '' set to false if digits are common cathode
According to the datasheet, these are common anode displays so you should leave it set to true.
I don't suppose you tried adding the "!activeBits" line?
I did with no meaningful results.
Here's essentially the same thing as the earlier code but with the anodes and cathodes reversed.
Well. Not 100% but getting there!!!!
I made an offer to purchase two of these for a total of $7.
Those are the ones. Mine did not come with the wires though. What a rip!!! I also only paid $2.00 for the one I bought with free shipping. They really jacked up the price on it.
There's a C to Spin converter somewhere. The schematic shown in the RobotShop is different than the schematic Jordan posted.
I changed the program to (hopefully) reflect the new schematic.
CON
_clkmode = xtal1 + pll16x
_xinfreq = 5_000_000
'' Pin Assignments
SHIFT_REGISTER_DATA = 0
SHIFT_REGISTER_CLOCK = 1
SHIFT_REGISTER_LATCH = 2
DIGITS = 8
MAX_DIGIT_INDEX = DIGITS - 1
MAX_DISPLAYABLE = 99_999_999
HIGH_DIGIT_DIVIDER = 10_000_000
SEGMENTS = 8
MAX_SEGMENT_INDEX = SEGMENTS - 1
BITS_TO_SHIFT = SEGMENTS + DIGITS
MAX_BIT_INDEX = BITS_TO_SHIFT - 1
SEGMENT_A = 1 << 7
SEGMENT_B = 1 << 6
SEGMENT_C = 1 << 5
SEGMENT_D = 1 << 4
SEGMENT_E = 1 << 3
SEGMENT_F = 1 << 2
SEGMENT_G = 1 << 1
SEGMENT_DP = 1 << 0
VAR
long shiftStack[64]
long fourDigitNumber
long shortInterval, longInterval
byte digitBits[DIGITS]
PUB Setup
'' This method starts in cog #0
'' This method starts one additional cog.
'' Presently there are six unused cogs.
shortInterval := clkfreq / 2 ' change "2" to 200 once program is working
longInterval := clkfreq * 4 ' comment out the "* 4" part to increase the speed
cognew(MaintainDigits, @shiftStack)
MainLoop
PUB MainLoop | digit, activeBits
repeat
repeat fourDigitNumber from 0 to MAX_DISPLAYABLE
waitcnt(longInterval + cnt)
PUB MaintainDigits | previousFourDigitNumber
'' This method runs in its own cog. It will continuously
'' display the value of "fourDigitNumber" on the 7-segment display.
dira[SHIFT_REGISTER_DATA] := 1 ' direction settings need to be done within cog using the pins
dira[SHIFT_REGISTER_CLOCK] := 1
dira[SHIFT_REGISTER_LATCH] := 1
previousFourDigitNumber := $7FFFFFFF ' some impossible number
repeat
if fourDigitNumber <> previousFourDigitNumber ' check to see if it's a new number
previousFourDigitNumber := fourDigitNumber
BustDigits(fourDigitNumber)
repeat result from 0 to MAX_DIGIT_INDEX ' result is used as a temporary variable
ShiftOutDigits(result, digitBits[result])
waitcnt(shortInterval + cnt) ' This line should be commented out or delay made very short
' once the program is working.
PUB BustDigits(numberToDisplay) | divisor
'' Convert a number to bits representing the segments
'' to light in a 7-segment display.
numberToDisplay <#= MAX_DISPLAYABLE
divisor := HIGH_DIGIT_DIVIDER
repeat result from 0 to MAX_DIGIT_INDEX
digitBits[result] := bitsInNumber[numberToDisplay / divisor]
numberToDisplay //= divisor
divisor /= 10
PUB ShiftOutDigits(digit, activeBits)
'' This methos moves the digit bit to the correct location and
'' combines the digit and segments bit together.
'' The combined bits are shifted out.
'' This method only displays a single digit at a time.
'' All 8 digits need to be cycled quickly to make them
'' all appear to be on.
'' our numbering system 0 1 2 3 4 5 6 7
digit := 1 << digit ' set the digit bit high
digit &= $FF ' only keep 8 bits (this shouldn't really be needed)
!activeBits ' invert segment bits, segments are cathodes
activeBits &= $FF ' only keep 8 bits (this shouldn't really be needed)
activeBits <<= 8 ' move segment bits to high bits (last to be clocked out)
activeBits |= digit ' "Or" the bits controlling the digits together with the
' bits controlling the segments.
' The top 8 bits control the digits and the bottom 8 bits
' control the segments.
repeat BITS_TO_SHIFT
outa[SHIFT_REGISTER_DATA] := activeBits
outa[SHIFT_REGISTER_CLOCK] := 1
outa[SHIFT_REGISTER_CLOCK] := 0
activeBits >>= 1
outa[SHIFT_REGISTER_LATCH] := 1
outa[SHIFT_REGISTER_LATCH] := 0
DAT
bitsInNumber byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_E | SEGMENT_F '0
byte SEGMENT_B | SEGMENT_C '1
byte SEGMENT_A | SEGMENT_B | SEGMENT_D | SEGMENT_E | SEGMENT_G '2
byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_G '3
byte SEGMENT_B | SEGMENT_C | SEGMENT_F | SEGMENT_G '4
byte SEGMENT_A | SEGMENT_C | SEGMENT_D | SEGMENT_F | SEGMENT_G '5
byte SEGMENT_A | SEGMENT_C | SEGMENT_D | SEGMENT_E | SEGMENT_F | SEGMENT_G '6
byte SEGMENT_A | SEGMENT_B | SEGMENT_C '7
byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_E | SEGMENT_F | SEGMENT_G '8
byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_F | SEGMENT_G '9
Only one digit will display at a time (for 1/2 second). To make all the digit light at once, you need to shorten the delay between updates. If the display appears to work correctly, then change the Setup method from:
PUB Setup '' This method starts in cog #0
'' This method starts one additional cog.
'' Presently there are six unused cogs.
shortInterval := clkfreq / 2 ' change "2" to 200 once program is working
longInterval := clkfreq * 4 ' comment out the "* 4" part to increase the speed
cognew(MaintainDigits, @shiftStack)
MainLoop
to:
PUB Setup '' This method starts in cog #0
'' This method starts one additional cog.
'' Presently there are six unused cogs.
[B]shortInterval := clkfreq / 200 [/B]
[B] longInterval := clkfreq [/B]
cognew(MaintainDigits, @shiftStack)
MainLoop
The changed code should start counting up my one each second (approximately). You can make "longInterval" shorter to increase the count speed.
Edit: I found some of the '595 displays. I had to search for "LED 74HC595".
I made an offer to purchase two of these for a total of $7.
My offer was turned down. I received a counteroffer of $7.90 for two which is only $0.08 less than the original price. It seems odd the seller has a "Make Offer" option when they'll only reduce the amount for multiple items by 1%.
I ended up only buying one. The odd thing is if the selling didn't have a "Make Offer" button, I probably would have purchased two units but since I went to the bother of submitting an offer, I didn't want to accept the insulting 1% discount. I think the seller would be better off removing the "Make Offer" button from their sale page.
I'm very curious to know how much shipping is on something like this. I would have thought shipping two items would have saved them more than eight cents?
Yea, I get frustrated some times wit the make offer option also. About 95% of the time it seems a reasonable offer is rejected. I will test the new code tomorrow. I am having vehicle issues right now and need to get that resolved.
I can't believe the amount of programming effort going into this. There are 16 outputs from the 2 '595's going to 16 inputs on the 2 led displays.
1- List the output pin numbers of the 2 '595's on a spreadsheet or piece of paper
2- get an ohmmeter, put it on the lowest ohms range
3- flip the display board over
4- put one lead of the ohmmeter on the first '595 pin
5- put the other ohmmeter lead on each of the display pins and write the pin# of the display pin with the lowest resistance next to the '595 pin#
6- repeat 5 for each of the output pins of the two '595's
Less than 10 minutes and you have all the information needed.
Shipping to: Worldwide
Excludes: Alaska/Hawaii, US Protectorates, APO/FPO, Africa, Asia, Central America and Caribbean, Europe, Middle East, North America, Oceania, Southeast Asia, South America
If you are in Antarctica or Australia you´re OK.
The display with the MAX7219 chip would be easier to program as it does the multiplexing for you, just ´shift & forget´.
Not yet. Since I am not real great at writing drivers I am waiting on @Duane Degn to receive his to see what he comes up with.
I probably will write a driver once I receive my display. I have a couple other 7-segment displays I want to control with '595 chips but I figure I'll wait until I receive the ebay display and just wire my other displays the same way as the ebay display so whatever driver I write will work with both displays.
Example video to go with post# 43. Sorry, for some reason my phone recorded it upside down!!!!
This was using code attached to post #38?
My display arrived today so I tried the code attached to post #38 and it almost behaved as expected except I had the digits reversed. So instead of 00000001 counting up it displayed 10000000 counting up with the least significant digit on the left instead of the right.
By changing line 131 from:
digit := 1 << digit ' set the digit bit high
to:
digit := 1 << (7 - digit) ' set the digit bit high
The order of the digits was fixed.
I then commented out line # 105
'waitcnt(shortInterval + cnt) ' This line should be commented out or delay made very short
' once the program is working.
and instead of only one digit being visible at a time, all the digits were lit.
I then changed line #77 from:
longInterval := clkfreq * 4 ' comment out the "* 4" part to increase the speed
to:
longInterval := clkfreq / 4
and now the displays counts up four units per second.
I don't understand why you had all "8"s?
I've attached the code with the above mentioned changes.
I wonder if I had something connected wrong. How is yours connected exactly?
I think you need to swap the clock and latch lines. I was able reproduce what you saw when I switched these lines.
This is how the pins should be connected:
SHIFT_REGISTER_DATA to pin labeled "DIO"
SHIFT_REGISTER_CLOCK to pin labeled "SCK"
SHIFT_REGISTER_LATCH to pin labeled "RCK"
I've noticed a lot of datasheets don't use the word "latch" when naming pins even though that's what everyone seems to call it.
I think the latch pin is called the "storage register clock" in many 74HC595 datasheets and the pin commonly called the "clock" pin is called the "shift register clock" in many datasheets.
I'm working on a better version of the code to make it easier to use with other programs.
The program attached to this post has the code to drive the shift registers in a child object.
The number to be displayed is set with the method "Set".
Instead of always having leading zeros, the leading character can now be set with the "SetPadBits" method. The demo program alternates between padding the display with zeros and leaving the extra digits blank.
The demo program just increments a counter 100 times a second and displays the count. The lowest digit is kind of a blur.
I don't have any support for decimal points yet. I'll probably add this tomorrow.
This latest version adds decimal point support (but not well).
You can either use "SetDp" which will place a single decimal point where told (and remove any previous decimal points) or you can use "AddDp" which doesn't delete previously set decimal points.
The "AddDp" method could be used to set decimal points between hours minutes and seconds on a clock or for some other application where one would want more than one decimal point.
Here's the display in action.
To be really useful, I should add a better way of adding the decimal point. If you wanted to display "0.0024" there isn't presently a way to do so unless you displayed "0000.0024".
I'm sure I'll improve the decimal point control sometime in the near future but if anyone needs this sort of control, let me know. I bet I could be talked into adding the feature sooner rather than later if someone needs it.
Use a byte that has bits set for each of the eight decimal points that should be on.
Use 5 bits per digit and set the dp bit based on bit 5.
Use ascii text, test to be sure the characters are in the range of 2E to 39 hex, mask off the 4 lsb's so the digits 0 to 9 become hex 0 to 9, and the decimal point and slash become E and F hex. When the E is detected the dp bit is set for that digit.
The first method is the simplest and has the added advantage of allowing for simplified leading zero suppression.
Comments
There are no current limiting resistors on the board or in the schematic. 5 V should not be a problem once the program is OK as then each digit should only on for max 1/8 of the time, a segment even less, but while you are testing the program it would probably be safer to use 3.3 V and even then make sure that a display is not on for too long or it might burn out.
I do not speak Spin, but in a BS2 my trial program would look like this;
' 2x4 7 segment display using 74HC595 shift register ' ' http://forums.parallax.com/showthread.php/157074-7-Segement-DisplayHelp-Needed ' ' {$STAMP BS2sx} ' {$PBASIC 2.5} ' DIOpin PIN 0 ' DS (Data Serial) CLKpin PIN 1 ' SHCP (Shift Clock Pulse) LATCHpin PIN 2 ' STCP (Storage Clock Pulse) ' ' digits: 12345678 2x4 digits Common Anode 7 segment display digit1 CON %10000000 ' digit 1 high = on, others low = off digit2 CON %01000000 ' digit 2 on digit3 CON %00100000 ' digit 3 on digit4 CON %00010000 ' digit 4 on digit5 CON %00001000 ' digit 5 on digit6 CON %00000100 ' digit 6 on digit7 CON %00000010 ' digit 7 on digit8 CON %00000001 ' digit 8 on ' ' segments: ' --a-- ' | | ' f b ' | | ' --g-- ' | | ' e c ' | | ' --d-- .dp ' ' abcdefgp zero CON %00000011 ' segments abcdef low = '0' one CON %10011111 ' segments bc low = '1' two CON %00100101 ' segments abged low = '2' three CON %01100001 ' segments afged low = '3' four CON %10011001 ' segments fbgc low = '4' five CON %01001001 ' segments afgcd low = '5' six CON %01000001 ' segments afgcde low = '6' (with flag) seven CON %00011111 ' segments abc low = '7' eight CON %00000011 ' segments abcdef low = '8' nine CON %00001001 ' segments abcdfg low = '9' (with flag) dp CON %11111110 ' segment dp low = '.' digitdata VAR Byte segmentdata VAR Byte ' ' =========================[ main ]================================ LOW LATCHpin ' initialise latch DO digitdata = digit1 ' set digit to light up segmentdata = one ' set segments to light up SHIFTOUT DIOpin, CLKpin, LSBFIRST, [segmentdata, digitdata] ' shift out data, show '1' on digit 1 PULSOUT LATCHpin, 1 ' make data visible SHIFTOUT DIOpin, CLKpin, LSBFIRST, [two, digit2] ' shift out data directly, show '2' on digit 2 PULSOUT LATCHpin, 1 ' make data visible SHIFTOUT DIOpin, CLKpin, LSBFIRST, [three, digit3] ' continue for all 8 digits, show '3' on digit 3 PULSOUT LATCHpin, 1 SHIFTOUT DIOpin, CLKpin, LSBFIRST, [four, digit4] ' show '4' on digit 4 PULSOUT LATCHpin, 1 SHIFTOUT DIOpin, CLKpin, LSBFIRST, [five, digit5] ' etc. PULSOUT LATCHpin, 1 SHIFTOUT DIOpin, CLKpin, LSBFIRST, [six, digit6] PULSOUT LATCHpin, 1 SHIFTOUT DIOpin, CLKpin, LSBFIRST, [seven, digit7] PULSOUT LATCHpin, 1 SHIFTOUT DIOpin, CLKpin, LSBFIRST, [eight, digit8] PULSOUT LATCHpin, 1 SHIFTOUT DIOpin, CLKpin, LSBFIRST, [dp, digit8] ' show decimal point on digit 8 PULSOUT LATCHpin, 1 LOOP 'forever ' ==================================================================================I will test it when I get home Thursday night. In the meantime I would suggest an ohmmeter or continuity tester to determine what pins are connected together. The '595 and display pinouts are known so it should only take 10 minutes or so to do that. Probably a lot easier than mucking around with untested programs.
I don't suppose you tried adding the "!activeBits" line?
Here's essentially the same thing as the earlier code but with the anodes and cathodes reversed.
CON _clkmode = xtal1 + pll16x _xinfreq = 5_000_000 '' Pin Assignments SHIFT_REGISTER_DATA = 0 SHIFT_REGISTER_CLOCK = 1 SHIFT_REGISTER_LATCH = 2 DIGITS = 8 MAX_DIGIT_INDEX = DIGITS - 1 MAX_DISPLAYABLE = 99_999_999 HIGH_DIGIT_DIVIDER = 10_000_000 SEGMENTS = 8 MAX_SEGMENT_INDEX = SEGMENTS - 1 BITS_TO_SHIFT = SEGMENTS + DIGITS MAX_BIT_INDEX = BITS_TO_SHIFT - 1 SEGMENT_A = 1 << 7 SEGMENT_B = 1 << 6 SEGMENT_C = 1 << 5 SEGMENT_D = 1 << 4 SEGMENT_E = 1 << 3 SEGMENT_F = 1 << 2 SEGMENT_G = 1 << 1 SEGMENT_DP = 1 << 0 COMMON_ANODE = true '' set to false if digits are common cathode VAR long shiftStack[64] long fourDigitNumber long shortInterval, longInterval byte digitBits[DIGITS] PUB Setup '' This method starts in cog #0 '' This method starts one additional cog. '' Presently there are six unused cogs. shortInterval := clkfreq / 2 longInterval := clkfreq * 4 cognew(MaintainDigits, @shiftStack) MainLoop PUB MainLoop | digit, activeBits repeat repeat fourDigitNumber from 0 to MAX_DISPLAYABLE waitcnt(longInterval + cnt) PUB MaintainDigits | previousFourDigitNumber '' This method runs in its own cog. It will continuously '' display the value of "fourDigitNumber" on the 7-segment display. dira[SHIFT_REGISTER_DATA] := 1 ' direction settings need to be done within cog using the pins dira[SHIFT_REGISTER_CLOCK] := 1 dira[SHIFT_REGISTER_LATCH] := 1 previousFourDigitNumber := $7FFFFFFF ' some impossible number repeat if fourDigitNumber <> previousFourDigitNumber ' check to see if it's a new number previousFourDigitNumber := fourDigitNumber BustDigits(fourDigitNumber) repeat result from 0 to MAX_DIGIT_INDEX ' result is used as a temporary variable ShiftOutDigits(result, digitBits[result]) waitcnt(shortInterval + cnt) ' This line should be commented out or delay made very short ' once the program is working. PUB BustDigits(numberToDisplay) | divisor '' Convert a number to bits representing the segments '' to light in a 7-segment display. numberToDisplay <#= MAX_DISPLAYABLE divisor := HIGH_DIGIT_DIVIDER repeat result from 0 to MAX_DIGIT_INDEX digitBits[result] := bitsInNumber[numberToDisplay / divisor] numberToDisplay //= divisor divisor /= 10 PUB ShiftOutDigits(digit, activeBits) '' This methos moves the digit bit to the correct location and '' combines the digit and segments bit together. '' The combined bits are shifted out. '' This method only displays a single digit at a time. '' All 8 digits need to be cycled quickly to make them '' all appear to be on. case digit ' convert digit to bit position 0..3: ' according to schematic what we call 0 - 3, they call 4 - 7 digit := 11 - digit ' range 11 - 8 4..7: digit := 19 - digit ' range 15 - 12 other: return '' our numbering system 0 1 2 3 4 5 6 7 '' the displays system 4 5 6 7 0 1 2 3 digit := 1 << digit ' set the digit bit high !digit ' invert the bits (only the digit bit will be low) digit &= $FF00 ' only keep top 8 bits activeBits &= $FF ' only keep bottom 8 bits activeBits |= digit ' "Or" the bits controlling the digits together with the ' bits controlling the segments. ' The top 8 bits control the digits and the bottom 8 bits ' control the segments. if COMMON_ANODE '' set this to false in CON section if it's a common cathode display !activeBits ' invert bits repeat BITS_TO_SHIFT outa[SHIFT_REGISTER_DATA] := activeBits outa[SHIFT_REGISTER_CLOCK] := 1 outa[SHIFT_REGISTER_CLOCK] := 0 activeBits >>= 1 outa[SHIFT_REGISTER_LATCH] := 1 outa[SHIFT_REGISTER_LATCH] := 0 DAT bitsInNumber byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_E | SEGMENT_F '0 byte SEGMENT_B | SEGMENT_C '1 byte SEGMENT_A | SEGMENT_B | SEGMENT_D | SEGMENT_E | SEGMENT_G '2 byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_G '3 byte SEGMENT_B | SEGMENT_C | SEGMENT_F | SEGMENT_G '4 byte SEGMENT_A | SEGMENT_C | SEGMENT_D | SEGMENT_F | SEGMENT_G '5 byte SEGMENT_A | SEGMENT_C | SEGMENT_D | SEGMENT_E | SEGMENT_F | SEGMENT_G '6 byte SEGMENT_A | SEGMENT_B | SEGMENT_C '7 byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_E | SEGMENT_F | SEGMENT_G '8 byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_F | SEGMENT_G '9I added a quarter of a second delay while each digit is displayed. You'll want to take this delay out (or shorten it) once you get a working program but the delay will help diagnose what's going on.
I also added a constant "COMMON_ANODE" which can be set to true or false.
According to the datasheet, these are common anode displays so you should leave it set to true.
The MAX7219 displays are very common on ebay. Here's one for $3.56 shipped.
Edit: I found some of the '595 displays. I had to search for "LED 74HC595".
I made an offer to purchase two of these for a total of $7.
Well. Not 100% but getting there!!!!
Those are the ones. Mine did not come with the wires though. What a rip!!! I also only paid $2.00 for the one I bought with free shipping. They really jacked up the price on it.
I changed the program to (hopefully) reflect the new schematic.
CON _clkmode = xtal1 + pll16x _xinfreq = 5_000_000 '' Pin Assignments SHIFT_REGISTER_DATA = 0 SHIFT_REGISTER_CLOCK = 1 SHIFT_REGISTER_LATCH = 2 DIGITS = 8 MAX_DIGIT_INDEX = DIGITS - 1 MAX_DISPLAYABLE = 99_999_999 HIGH_DIGIT_DIVIDER = 10_000_000 SEGMENTS = 8 MAX_SEGMENT_INDEX = SEGMENTS - 1 BITS_TO_SHIFT = SEGMENTS + DIGITS MAX_BIT_INDEX = BITS_TO_SHIFT - 1 SEGMENT_A = 1 << 7 SEGMENT_B = 1 << 6 SEGMENT_C = 1 << 5 SEGMENT_D = 1 << 4 SEGMENT_E = 1 << 3 SEGMENT_F = 1 << 2 SEGMENT_G = 1 << 1 SEGMENT_DP = 1 << 0 VAR long shiftStack[64] long fourDigitNumber long shortInterval, longInterval byte digitBits[DIGITS] PUB Setup '' This method starts in cog #0 '' This method starts one additional cog. '' Presently there are six unused cogs. shortInterval := clkfreq / 2 ' change "2" to 200 once program is working longInterval := clkfreq * 4 ' comment out the "* 4" part to increase the speed cognew(MaintainDigits, @shiftStack) MainLoop PUB MainLoop | digit, activeBits repeat repeat fourDigitNumber from 0 to MAX_DISPLAYABLE waitcnt(longInterval + cnt) PUB MaintainDigits | previousFourDigitNumber '' This method runs in its own cog. It will continuously '' display the value of "fourDigitNumber" on the 7-segment display. dira[SHIFT_REGISTER_DATA] := 1 ' direction settings need to be done within cog using the pins dira[SHIFT_REGISTER_CLOCK] := 1 dira[SHIFT_REGISTER_LATCH] := 1 previousFourDigitNumber := $7FFFFFFF ' some impossible number repeat if fourDigitNumber <> previousFourDigitNumber ' check to see if it's a new number previousFourDigitNumber := fourDigitNumber BustDigits(fourDigitNumber) repeat result from 0 to MAX_DIGIT_INDEX ' result is used as a temporary variable ShiftOutDigits(result, digitBits[result]) waitcnt(shortInterval + cnt) ' This line should be commented out or delay made very short ' once the program is working. PUB BustDigits(numberToDisplay) | divisor '' Convert a number to bits representing the segments '' to light in a 7-segment display. numberToDisplay <#= MAX_DISPLAYABLE divisor := HIGH_DIGIT_DIVIDER repeat result from 0 to MAX_DIGIT_INDEX digitBits[result] := bitsInNumber[numberToDisplay / divisor] numberToDisplay //= divisor divisor /= 10 PUB ShiftOutDigits(digit, activeBits) '' This methos moves the digit bit to the correct location and '' combines the digit and segments bit together. '' The combined bits are shifted out. '' This method only displays a single digit at a time. '' All 8 digits need to be cycled quickly to make them '' all appear to be on. '' our numbering system 0 1 2 3 4 5 6 7 digit := 1 << digit ' set the digit bit high digit &= $FF ' only keep 8 bits (this shouldn't really be needed) !activeBits ' invert segment bits, segments are cathodes activeBits &= $FF ' only keep 8 bits (this shouldn't really be needed) activeBits <<= 8 ' move segment bits to high bits (last to be clocked out) activeBits |= digit ' "Or" the bits controlling the digits together with the ' bits controlling the segments. ' The top 8 bits control the digits and the bottom 8 bits ' control the segments. repeat BITS_TO_SHIFT outa[SHIFT_REGISTER_DATA] := activeBits outa[SHIFT_REGISTER_CLOCK] := 1 outa[SHIFT_REGISTER_CLOCK] := 0 activeBits >>= 1 outa[SHIFT_REGISTER_LATCH] := 1 outa[SHIFT_REGISTER_LATCH] := 0 DAT bitsInNumber byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_E | SEGMENT_F '0 byte SEGMENT_B | SEGMENT_C '1 byte SEGMENT_A | SEGMENT_B | SEGMENT_D | SEGMENT_E | SEGMENT_G '2 byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_G '3 byte SEGMENT_B | SEGMENT_C | SEGMENT_F | SEGMENT_G '4 byte SEGMENT_A | SEGMENT_C | SEGMENT_D | SEGMENT_F | SEGMENT_G '5 byte SEGMENT_A | SEGMENT_C | SEGMENT_D | SEGMENT_E | SEGMENT_F | SEGMENT_G '6 byte SEGMENT_A | SEGMENT_B | SEGMENT_C '7 byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_E | SEGMENT_F | SEGMENT_G '8 byte SEGMENT_A | SEGMENT_B | SEGMENT_C | SEGMENT_D | SEGMENT_F | SEGMENT_G '9Only one digit will display at a time (for 1/2 second). To make all the digit light at once, you need to shorten the delay between updates. If the display appears to work correctly, then change the Setup method from:
to:
The changed code should start counting up my one each second (approximately). You can make "longInterval" shorter to increase the count speed.
My offer was turned down. I received a counteroffer of $7.90 for two which is only $0.08 less than the original price. It seems odd the seller has a "Make Offer" option when they'll only reduce the amount for multiple items by 1%.
I ended up only buying one. The odd thing is if the selling didn't have a "Make Offer" button, I probably would have purchased two units but since I went to the bother of submitting an offer, I didn't want to accept the insulting 1% discount. I think the seller would be better off removing the "Make Offer" button from their sale page.
I'm very curious to know how much shipping is on something like this. I would have thought shipping two items would have saved them more than eight cents?
1- List the output pin numbers of the 2 '595's on a spreadsheet or piece of paper
2- get an ohmmeter, put it on the lowest ohms range
3- flip the display board over
4- put one lead of the ohmmeter on the first '595 pin
5- put the other ohmmeter lead on each of the display pins and write the pin# of the display pin with the lowest resistance next to the '595 pin#
6- repeat 5 for each of the output pins of the two '595's
Less than 10 minutes and you have all the information needed.
The display with the MAX7219 chip would be easier to program as it does the multiplexing for you, just ´shift & forget´.
Now can you make it display e.g. "12345678" continuously?
I probably will write a driver once I receive my display. I have a couple other 7-segment displays I want to control with '595 chips but I figure I'll wait until I receive the ebay display and just wire my other displays the same way as the ebay display so whatever driver I write will work with both displays.
This was using code attached to post #38?
My display arrived today so I tried the code attached to post #38 and it almost behaved as expected except I had the digits reversed. So instead of 00000001 counting up it displayed 10000000 counting up with the least significant digit on the left instead of the right.
By changing line 131 from:
to:
The order of the digits was fixed.
I then commented out line # 105
'waitcnt(shortInterval + cnt) ' This line should be commented out or delay made very short ' once the program is working.and instead of only one digit being visible at a time, all the digits were lit.
I then changed line #77 from:
to:
and now the displays counts up four units per second.
I don't understand why you had all "8"s?
I've attached the code with the above mentioned changes.
I think you need to swap the clock and latch lines. I was able reproduce what you saw when I switched these lines.
This is how the pins should be connected:
SHIFT_REGISTER_DATA to pin labeled "DIO"
SHIFT_REGISTER_CLOCK to pin labeled "SCK"
SHIFT_REGISTER_LATCH to pin labeled "RCK"
I've noticed a lot of datasheets don't use the word "latch" when naming pins even though that's what everyone seems to call it.
I think the latch pin is called the "storage register clock" in many 74HC595 datasheets and the pin commonly called the "clock" pin is called the "shift register clock" in many datasheets.
I'm working on a better version of the code to make it easier to use with other programs.
The number to be displayed is set with the method "Set".
Instead of always having leading zeros, the leading character can now be set with the "SetPadBits" method. The demo program alternates between padding the display with zeros and leaving the extra digits blank.
The demo program just increments a counter 100 times a second and displays the count. The lowest digit is kind of a blur.
I don't have any support for decimal points yet. I'll probably add this tomorrow.
You can either use "SetDp" which will place a single decimal point where told (and remove any previous decimal points) or you can use "AddDp" which doesn't delete previously set decimal points.
The "AddDp" method could be used to set decimal points between hours minutes and seconds on a clock or for some other application where one would want more than one decimal point.
Here's the display in action.
To be really useful, I should add a better way of adding the decimal point. If you wanted to display "0.0024" there isn't presently a way to do so unless you displayed "0000.0024".
I'm sure I'll improve the decimal point control sometime in the near future but if anyone needs this sort of control, let me know. I bet I could be talked into adding the feature sooner rather than later if someone needs it.
EDIT: I think I have a bad unit. It pretty much does nothing now. It shows a few almost sevens but that is it.
Use a byte that has bits set for each of the eight decimal points that should be on.
Use 5 bits per digit and set the dp bit based on bit 5.
Use ascii text, test to be sure the characters are in the range of 2E to 39 hex, mask off the 4 lsb's so the digits 0 to 9 become hex 0 to 9, and the decimal point and slash become E and F hex. When the E is detected the dp bit is set for that digit.
The first method is the simplest and has the added advantage of allowing for simplified leading zero suppression.