Seems the device itself is not I2C compliant then SDA is allowed to do whatever it likes while the clock is low as transitions on SDA while clock is high have the START/STOP condition meanings.
However if you change this second line in I2C! (also I2C!?) from:
I need a little help with SWITCH CASE BREAK.
I am probably thinking about this incorrectly but it seems to me there needs to be CASE ELSE and CASE END structure.
Maybe there is a way to do CASE ELSE with the existing words . . .
Also it seems instructions in the same block after the last CASE BREAK are ignored.
Okay, I can see now that the code after the last BREAK functions as CASE ELSE but how do I do CASE END?
Hi Art,
The Tachyon Select/Case structure is similar, but also different from C.
- there is no END CASE - so SELECTS can not be nested directly.
It works very simple.
SELECT stores a value into the compare variable.
CASE compares a given value with the stored compare variable value
and then performs an IF. BREAK defines the end of the IF.
A new SELECT just stores a new value into the compare variable.
{ TACHYON CASE STRUCTURES
This implementation follows the C method to some degree.
Each CASE statement simply compares the supplied value with the SWITCH and executes an IF
To prevent the IF statement from falling through a BREAK is used (also acts as a THEN at CT)
The SWITCH can be tested directly and a manual CASE can be constructed with IF <code> BREAK
SWITCH ( switch -- ) \ Save switch value used in CASE structure
CASE ( val -- ) \ compare val with switch and perform an IF. Equivalent to SWITCH= IF
BREAK \ EXIT (return) but also completes IF structure at CT. Equivalent to EXIT THEN
\ extra functions to allow the switch to be manipulated etc
SWITCH@ ( -- switch ) \ Fetch last saved switch value
SWITCH= ( val -- flg ) \ Compare val with switch. Equivalent to SWITCH@ =
SWITCH>< ( from to -- flg ) \ Compare switch within range. Equivalent to SWITCH@ ROT ROT WITHIN
Usage:
pub CASEDEMO ( val -- )
SWITCH \ use the key value as a switch in the case statement
"A" CASE CR ." A is for APPLE " BREAK
"H" CASE CR ." H is for HAPPY " BREAK
"Z" CASE CR ." Z is for ZEBRA " BREAK
$08 CASE 4 REG ~ BREAK
\ Now accept 0 to 9 and build a number calculator style
"0" "9" SWITCH>< IF SWITCH@ $30 - 4 REG @ #10 * + 4 REG ! ." *" BREAK
\ On enter just display the accumulated number
$0D CASE CR ." and our lucky number is " 4 REG @ .DEC BREAK
\ show how we can test more than one value
"Q" SWITCH= "X" SWITCH= OR IF CR ." So you're a quitter hey?" CR CONSOLE BREAK
CR ." I don't know what " SWITCH@ EMIT ." is"
;
pub DEMO
BEGIN WKEY UPPER CASEDEMO AGAIN
;
Thanks, MJB. I am not C literate so I am not familiar with the SELECT word you mention. I suppose you are referring to the conditions tested by the CASE words. My problem is that code after I am finished testing for the SWITCH is treated as a CASE ELSE in that it is only processed if none of the cases are true. If one of the cases is true the code following the last BREAK is skipped. I don't understand how to work with that. The rest is indeed simple and I have previously studied the source and can't find an answer. Maybe the Forth word has to end after the last BREAK. . . ?
There is one thing to watch with this switch case break in that since the break is compiled as a "exit then" then it won't try to execute anything else as if you could tell it to jump to an end case and continue. This keeps it simple and efficient and so you should factor the case statements together in their own routine rather than one big long routine that continues on and on long after.
Hi Sven, since the I2C chip responds it must be working but bear in mind that the 8574 doesn't have a direction register, only open-drain outputs with "pullups". In reality you can only write zeros to pull the output down as a one will simply leave it in input mode.
So since there are no direction registers there is only the one implicit source and destination. You have tried to specify a register address 1 which is in fact the data that gets written to the port 1 $40 IO!, not quite what you meant.
I found the code you must have loaded for these routines:
\ Write to the port of the chip specified
pub IO! ( data chip -- )
I2CSTART I2C! I2C! I2CSTOP
;
\ Read the port of the chip specified (using full 8-bit address)
\ a negative ack (1) is used when reading to tell the chip that no more bytes will be read
pub IO@ ( chip -- data )
I2CSTART 1+ I2C! 1 I2C@ I2CSTOP
;
There is one thing to watch with this switch case break in that since the break is compiled as a "exit then" then it won't try to execute anything else as if you could tell it to jump to an end case and continue. This keeps it simple and efficient and so you should factor the case statements together in their own routine rather than one big long routine that continues on and on long after.
Thanks Peter. That's what I was beginning to suspect. Will do. Now that I understand that point it should work great.
and I thought that P0 - P7 of the 8574 drop from high level to low level,
but they didn't .
If I connect a pulldown resistor from P0 to ground and type lsi2c I get:
lsi2c Scanning I2C bus
Fast I/O EXPANDER #0 at $41: FE FE FE FE FE FE FE FE FE FE FE FE FE FE FE FE
Fast EEPROM or RTC #0 at $A1: 6F 8C 10 00 7C 7E 84 7E 50 7E 88 7E 6C 7E 02 00
I was expecting SERIN to work like KEY but instead it is like WKEY except that it returns with the port mask pushed onto the stack below the data. This can be removed with a NIP of course. Is this how it is intended to work?
and I thought that P0 - P7 of the 8574 drop from high level to low level,
but they didn't .
If I connect a pulldown resistor from P0 to ground and type lsi2c I get:
lsi2c Scanning I2C bus
Fast I/O EXPANDER #0 at $41: FE FE FE FE FE FE FE FE FE FE FE FE FE FE FE FE
Fast EEPROM or RTC #0 at $A1: 6F 8C 10 00 7C 7E 84 7E 50 7E 88 7E 6C 7E 02 00
So I think the reading works.
Sven
I finally managed to locate an actual PCF8574 and tried it out but the device wasn't happy at all. So I specifically used the slow I2C routines to write to the device and it worked fine.
$F0 $40 I2CSTART I2C! SI2C! I2CSTOP ok
lsi2c Scanning I2C bus
Fast I/O EXPANDER #0 at $41: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ok
I2CSTART $40 SI2C! $F0 SI2C! I2CSTOP ok
lsi2c Scanning I2C bus
Fast I/O EXPANDER #0 at $41: F0 F0 F0 F0 F0 F0 F0 F0 F0 F0 F0 F0 F0 F0 F0 F0 ok
I think the original PCF8574 is probably still spec'd to run at 100kHz in an age when 400kHz is standard so you could modify the routines as such:
\ Write to the port of the chip specified
pub IO! ( data chip -- )
I2CSTART SI2C! SI2C! I2CSTOP
;
\ Read the port of the chip specified (using full 8-bit address)
\ a negative ack (1) is used when reading to tell the chip that no more bytes will be read
pub IO@ ( chip -- data )
I2CSTART 1+ SI2C! 1 SI2C@ I2CSTOP
;
I was expecting SERIN to work like KEY but instead it is like WKEY except that it returns with the port mask pushed onto the stack below the data. This can be removed with a NIP of course. Is this how it is intended to work?
Have never seen it do that but I did a quick test using P31 as the input
!!SP ok
.S Data Stack (1)
$DEAD.BEEF - -559038737 ok
31 SERIN ok
.S Data Stack (2)
$0000.00FF - 255
$DEAD.BEEF - -559038737 ok
The $FF is the data I'd expect to see due to difference between the SERIN baudrate and the console's baudrate.
Make sure you have the current EXTEND.fth for whatever reason. SERIN should look like this:
pub SERIN ( pin -- data \ receive 8 bit serial data from pin at rate set with SERBAUD, blocks )
MASK DUP 3 COGREG! --- [5.8us]
baudcnt @ 2/ 200 - --- [4.8us] serup half-bit delay with high speed compensation
(WAITPEQ) --- [0.4us+] make sure we are not detecting the last data bit - wait for stop
(WAITPNE) DELTA --- wait for start bit then wait haf bit time
0 --- [5.4us] setup pin mask and inital data to SHRINP 8 data
baudcnt @ DELTA --- delay to sample 1 bit later in 1st data bit
SHRINP WAITCNT
SHRINP WAITCNT
SHRINP WAITCNT
SHRINP WAITCNT
SHRINP WAITCNT
SHRINP WAITCNT
SHRINP WAITCNT
SHRINP --- last data bit
NIP #24 SHR --- right justify 8-bit data
;
After loading EXTEND.FTH I load some utility words before my project.
This line seems to be causing problems.
ALIAS PRINT$ .$
I was trying to reload the whole thing by forgetting the first of the utility words and the console froze.
So I started a binary search for the prob. I found that it is okay to FORGET any place in the file after the ALIAS line.
: motor.FTH ." Motor driver for Jimmy the mouse bot " ;
{
Motor driver for Jimmy the mouse bot.
Using L298 compact motor driver H bridge - Solarbotics
P26 enable right motor
P27 enable left motor
P22 L1
P23 L2
P24 L3
P25 L4
start with initpwm to initialize the PWM
}
DECIMAL
\ 1 - allocate memory for a table
256 LONGS pwms \ allocate a 256 longs table for the PWM samples
: initpwm
\ 2 - specify the outputs and the address of the table then the freq and start the PWM cog
\ Start up PWM using from P0..7, P16..P23 for 16 channels
\ PWM.START ( iomask table freq -- )
\ %00000110_00000000_11111111_11111111
: driveahead
\ 3 - set the duty cycle for individual pins or groups of pins
100 % 26 SETPWM
100 % 27 SETPWM
\ motors drive ahead
\ left motor
#P22 LOW
#P23 HIGH
\ right motor
#P24 LOW
#P25 HIGH
;
: drivebackw
\ drive backwards
100 % 26 SETPWM
100 % 27 SETPWM
\ left motor
#P22 HIGH
#P23 LOW
\ right motor
#P24 HIGH
#P25 LOW
;
: driveleft
100 % 26 SETPWM
90 % 27 SETPWM
\ motors drive ahead
\ left motor
#P22 LOW
#P23 HIGH
\ right motor
#P24 LOW
#P25 HIGH
;
: driveright
90 % 26 SETPWM
100 % 27 SETPWM
\ motors drive ahead
\ left motor
#P22 LOW
#P23 HIGH
\ right motor
#P24 LOW
#P25 HIGH
;
\ tank style on place turning
: turnright
50 % 26 SETPWM
50 % 27 SETPWM
\ motors drive ahead
\ left motor
#P22 LOW
#P23 HIGH
\ right motor
#P24 HIGH
#P25 LOW
;
: turnleft
50 % 26 SETPWM
50 % 27 SETPWM
\ motors drive ahead
\ left motor
#P22 HIGH
#P23 LOW
\ right motor
#P24 LOW
#P25 HIGH
;
: drivestop
\ switch motors off
1 % 26 SETPWM
1 % 27 SETPWM
\ left motor
#P22 LOW
#P23 LOW
\ right motor
#P24 LOW
#P25 LOW
;
]~
END
And run the following:
initpwm ok
driveahead ok
drivestop ok
turnright ok
drivestop ok
I have also tried
motor.FTH
initpwm ok
driveahead ok
drivestop ok
turnright ok
drivestop ok
While the motors turn, there is no signs of PWM on P26 and P27, they are 100% on all the time.
I have spent the last couple of days on this, tried the .24 Forth as well and older Extend.
Thanks Peter,
that' s it, with 100 kHz it works. I should better read the product specifications next time.
The PCF8574 data sheet shows a maximum SCL clock frequency of 100kHz .
Early days with TF so please correct me if I am wrong...
I run out of memory if I try to load SDCARD and Easyfile on with Extend.
Even though the code is very compact the dictionary is not and can consume 10k so there is EEWORDS.fth that gets loaded sometime after EXTEND and the idea is to load your application last so add the filesystem functions and assuming you have 64k of EEPROM you can tell it to COMPACT the current dictionary into upper EEPROM. Thereafter you can load up your application normally with plenty of room to spare.
Once this is done you can still load and forget your application but if for some reason you need to change any of the compacted words you will need to do this from a cold start.
Looks like i am up the well known creek, I am using a propstick atm,
Key Features:
Propeller P8X32A-M44 chip
32 KB 24LC256-I/ST EEPROM
FTDI FT232RG and mini USB connector
USB data transfer indicator LEDs
5 MHz crystal in a removable socket
3.3 V, 500 mA voltage regulator
Reset pushbutton switch
Before I started using the upper EEPROM for the dictionary I was using the SD card so there is an older version called SDWORDS.fth that you could use although the dictionary is then dependant on having the dictionary file on the SD and inserted! I hadn't bothered to use the EEPROM initially because it is very slow but I came up with a fast and efficient method that despite running out of EEPROM ends up about the same speed as RAM.
Parallax uses 64k EEPROMs these days but If you can consider replacing the EEPROM then don't worry about desoldering as if you were ever going to reuse the old chip again. I just gently press down on the pins with a craft knife so that the chip is removed then just run your iron over the pads to remove the pins, maybe with a blob of fresh solder or some flux. Best to press on the pin close to the chip body and brace your hand so that it doesn't want to jab into the pcb afterwards although this method is very safe and reliable and much better than desoldering or even trying to cut the pins (vs pressing).
btw, the 500ma figure for the regulator is practically useless, if you feed it from 5V that means at 500ma it would dissipate 1.7*0.5 = 850mW which is a lot of heat. The 500ma figure is probably only good for a 3.7V input. Never accept these figures for linear regs without taking power handling into consideration. Also I noticed the Propstick has the crystal in a socket which might be handy for the bench but please solder the crystal in if you intend to embed the Propstick.
I need a little help redirecting the console in and out.
I am using this for a robot and can not remove the existing serial hardware so would like to preferably add a second in / out to be live at the same time as the original console or redirect the original console.
Since the receive and transmit routines rely on masks it is possible to receive exclusively from any receive input and to transmit to many outputs simultaneously. The snag is that while the transmit mask is easy to update on the fly the receive isn't as it is running in its own cog and you can't do a coginit again as the cog image as been reused in hub for the buffer. However the receive routine could be updated in source to update this mask from hub so that you could dynamically allocate rx and tx from the one receive cog. I will try and make the changes later.
Of course you could use SERIN but unfortunately it blocks while waiting for a character. I have been meaning to add some enhancements to Tachyon and more flexible serial I/O might be one of them.
Comments
However if you change this second line in I2C! (also I2C!?) from: to
it should keep that non-compliant chip happy.
I am probably thinking about this incorrectly but it seems to me there needs to be CASE ELSE and CASE END structure.
Maybe there is a way to do CASE ELSE with the existing words . . .
Also it seems instructions in the same block after the last CASE BREAK are ignored.
What am I missing?
Standby -
Hi Art,
The Tachyon Select/Case structure is similar, but also different from C.
- there is no END CASE - so SELECTS can not be nested directly.
It works very simple.
SELECT stores a value into the compare variable.
CASE compares a given value with the stored compare variable value
and then performs an IF. BREAK defines the end of the IF.
A new SELECT just stores a new value into the compare variable.
{ TACHYON CASE STRUCTURES This implementation follows the C method to some degree. Each CASE statement simply compares the supplied value with the SWITCH and executes an IF To prevent the IF statement from falling through a BREAK is used (also acts as a THEN at CT) The SWITCH can be tested directly and a manual CASE can be constructed with IF <code> BREAK SWITCH ( switch -- ) \ Save switch value used in CASE structure CASE ( val -- ) \ compare val with switch and perform an IF. Equivalent to SWITCH= IF BREAK \ EXIT (return) but also completes IF structure at CT. Equivalent to EXIT THEN \ extra functions to allow the switch to be manipulated etc SWITCH@ ( -- switch ) \ Fetch last saved switch value SWITCH= ( val -- flg ) \ Compare val with switch. Equivalent to SWITCH@ = SWITCH>< ( from to -- flg ) \ Compare switch within range. Equivalent to SWITCH@ ROT ROT WITHIN Usage: pub CASEDEMO ( val -- ) SWITCH \ use the key value as a switch in the case statement "A" CASE CR ." A is for APPLE " BREAK "H" CASE CR ." H is for HAPPY " BREAK "Z" CASE CR ." Z is for ZEBRA " BREAK $08 CASE 4 REG ~ BREAK \ Now accept 0 to 9 and build a number calculator style "0" "9" SWITCH>< IF SWITCH@ $30 - 4 REG @ #10 * + 4 REG ! ." *" BREAK \ On enter just display the accumulated number $0D CASE CR ." and our lucky number is " 4 REG @ .DEC BREAK \ show how we can test more than one value "Q" SWITCH= "X" SWITCH= OR IF CR ." So you're a quitter hey?" CR CONSOLE BREAK CR ." I don't know what " SWITCH@ EMIT ." is" ; pub DEMO BEGIN WKEY UPPER CASEDEMO AGAIN ;I've uploaded the Tachyon explorer and got the follwing boot screen:
Propeller .:.:--TACHYON--:.:. Forth V27150720.2030
VER: Propeller .:.:--TACHYON--:.:. Forth V27150720.2030
FREQ: 80MHZ (PLLEN OSCEN XTAL1 PLL16X)
NAMES: $5567...716B for 7,172 bytes (+4,662)
CODE: $0924...3F13 for 13,807 bytes (+9,362)
CALLS: 333 vectors free
RAM: 5,716 bytes free
BUILD: FIRMWARE BUILD DATE 967295:967295
BOOTS: 8
BOOT: EXTEND.boot
POLL:
MODULES LOADED:
1A81: EXTEND.fth Tachyon Forth Propeller hardware debugger and explorer - 1500
I have a PCF8574 expander board connected to pin 28,29 of the Propeller.
After I type "lsi2c" serveral times I got these results:
lsi2c Scanning I2C bus
Fast I/O EXPANDER #0 at $41: F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2
Fast EEPROM or RTC #0 at $A1: C7 F4 F0 87 96 14 2C 35 C7 FC 80 C7 FC 80 C4 F4 ok
lsi2c Scanning I2C bus
Fast I/O EXPANDER #0 at $41: F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2
Fast EEPROM or RTC #0 at $A1: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ok
lsi2c Scanning I2C bus
Fast I/O EXPANDER #0 at $41: F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2
Fast EEPROM or RTC #0 at $A1: 56 43 46 47 82 B8 37 04 56 53 43 4C 82 B8 38 03 ok
lsi2c Scanning I2C bus
Fast I/O EXPANDER #0 at $41: F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2
Fast EEPROM or RTC #0 at $A1: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ok
lsi2c Scanning I2C bus
Fast I/O EXPANDER #0 at $41: F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2
Fast EEPROM or RTC #0 at $A1: 6F 8C 10 00 7C 7E 84 7E 50 7E 88 7E 6C 7E 02 00 ok
lsi2c Scanning I2C bus
Fast I/O EXPANDER #0 at $41: F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 F2
Fast EEPROM or RTC #0 at $A1: 6F 8C 10 00 7C 7E 84 7E 50 7E 88 7E 6C 7E 02 00 ok
I tried the example from the "I2C I/O EXPANDERS" document :
$F0 3 $40 IO! \ Set 0..3 as outputs
7 1 $40 IO! \ Write 7 to outputs
0 $40 IO@ \ Read the inputs
No matter what I write to the output I always read $F2 back.
First I thought the expander board could be broken but it works without problems at an Arduino.
Any ides what could be wrong ?
Sven
So since there are no direction registers there is only the one implicit source and destination. You have tried to specify a register address 1 which is in fact the data that gets written to the port 1 $40 IO!, not quite what you meant.
I found the code you must have loaded for these routines:
\ Write to the port of the chip specified pub IO! ( data chip -- ) I2CSTART I2C! I2C! I2CSTOP ; \ Read the port of the chip specified (using full 8-bit address) \ a negative ack (1) is used when reading to tell the chip that no more bytes will be read pub IO@ ( chip -- data ) I2CSTART 1+ I2C! 1 I2C@ I2CSTOP ;This is perhaps what you meant:
7 $40 IO!
$40 IO@
Thanks Peter. That's what I was beginning to suspect. Will do. Now that I understand that point it should work great.
I've tried the follwing now:
: test I2CSTART $40 I2C! 0 I2C! I2CSTOP ;
and I thought that P0 - P7 of the 8574 drop from high level to low level,
but they didn't .
If I connect a pulldown resistor from P0 to ground and type lsi2c I get:
lsi2c Scanning I2C bus
Fast I/O EXPANDER #0 at $41: FE FE FE FE FE FE FE FE FE FE FE FE FE FE FE FE
Fast EEPROM or RTC #0 at $A1: 6F 8C 10 00 7C 7E 84 7E 50 7E 88 7E 6C 7E 02 00
So I think the reading works.
Sven
I finally managed to locate an actual PCF8574 and tried it out but the device wasn't happy at all. So I specifically used the slow I2C routines to write to the device and it worked fine.
I think the original PCF8574 is probably still spec'd to run at 100kHz in an age when 400kHz is standard so you could modify the routines as such:
\ Write to the port of the chip specified pub IO! ( data chip -- ) I2CSTART SI2C! SI2C! I2CSTOP ; \ Read the port of the chip specified (using full 8-bit address) \ a negative ack (1) is used when reading to tell the chip that no more bytes will be read pub IO@ ( chip -- data ) I2CSTART 1+ SI2C! 1 SI2C@ I2CSTOP ;Trying that out:Have never seen it do that but I did a quick test using P31 as the input The $FF is the data I'd expect to see due to difference between the SERIN baudrate and the console's baudrate.
Make sure you have the current EXTEND.fth for whatever reason. SERIN should look like this:
This line seems to be causing problems.
ALIAS PRINT$ .$
I was trying to reload the whole thing by forgetting the first of the utility words and the console froze.
So I started a binary search for the prob. I found that it is okay to FORGET any place in the file after the ALIAS line.
Is there something wrong with that line?
@Peter Jakacki
Hi Peter,
Should PWM be working with the latest Forth and Extend? I am using:
MODULES LOADED:
1A81: EXTEND.fth Tachyon Forth Propeller hardware debugger and explorer - 150902-0100
VER: Propeller .:.:--TACHYON--:.:. Forth V27150902.0100
FREQ: 80MHZ (PLLEN OSCEN XTAL1 PLL16X)
NAMES: $5491...7163 for 7,378 bytes (+125)
CODE: $0924...4482 for 15,198 bytes (+1,309)
CALLS: 315 vectors free
RAM: 4,111 bytes free
BUILD: FIRMWARE BUILD DATE 654545:466585
BOOTS: 1
BOOT: EXTEND.boot
POLL:
I then load this code:
TACHYON [~
: motor.FTH ." Motor driver for Jimmy the mouse bot " ;
{
Motor driver for Jimmy the mouse bot.
Using L298 compact motor driver H bridge - Solarbotics
P26 enable right motor
P27 enable left motor
P22 L1
P23 L2
P24 L3
P25 L4
start with initpwm to initialize the PWM
}
DECIMAL
\ 1 - allocate memory for a table
256 LONGS pwms \ allocate a 256 longs table for the PWM samples
: initpwm
\ 2 - specify the outputs and the address of the table then the freq and start the PWM cog
\ Start up PWM using from P0..7, P16..P23 for 16 channels
\ PWM.START ( iomask table freq -- )
\ %00000110_00000000_11111111_11111111
%00001100_00000000_00000000_00000000 pwms 6000 PWM.START
;
: driveahead
\ 3 - set the duty cycle for individual pins or groups of pins
100 % 26 SETPWM
100 % 27 SETPWM
\ motors drive ahead
\ left motor
#P22 LOW
#P23 HIGH
\ right motor
#P24 LOW
#P25 HIGH
;
: drivebackw
\ drive backwards
100 % 26 SETPWM
100 % 27 SETPWM
\ left motor
#P22 HIGH
#P23 LOW
\ right motor
#P24 HIGH
#P25 LOW
;
: driveleft
100 % 26 SETPWM
90 % 27 SETPWM
\ motors drive ahead
\ left motor
#P22 LOW
#P23 HIGH
\ right motor
#P24 LOW
#P25 HIGH
;
: driveright
90 % 26 SETPWM
100 % 27 SETPWM
\ motors drive ahead
\ left motor
#P22 LOW
#P23 HIGH
\ right motor
#P24 LOW
#P25 HIGH
;
\ tank style on place turning
: turnright
50 % 26 SETPWM
50 % 27 SETPWM
\ motors drive ahead
\ left motor
#P22 LOW
#P23 HIGH
\ right motor
#P24 HIGH
#P25 LOW
;
: turnleft
50 % 26 SETPWM
50 % 27 SETPWM
\ motors drive ahead
\ left motor
#P22 HIGH
#P23 LOW
\ right motor
#P24 LOW
#P25 HIGH
;
: drivestop
\ switch motors off
1 % 26 SETPWM
1 % 27 SETPWM
\ left motor
#P22 LOW
#P23 LOW
\ right motor
#P24 LOW
#P25 LOW
;
]~
END
And run the following:
initpwm ok
driveahead ok
drivestop ok
turnright ok
drivestop ok
I have also tried
motor.FTH
initpwm ok
driveahead ok
drivestop ok
turnright ok
drivestop ok
While the motors turn, there is no signs of PWM on P26 and P27, they are 100% on all the time.
I have spent the last couple of days on this, tried the .24 Forth as well and older Extend.
Any suggestions?
many thanks
Lee
The % got reused for more general use so that would mess up your stuff for starters.
BTW, try enclosing your code in the code attribute just next to the strikeout in the posting menu or select and type ctrl+o
that' s it, with 100 kHz it works. I should better read the product specifications next time.
The PCF8574 data sheet shows a maximum SCL clock frequency of 100kHz .
Sven
That was the problem, I took out the % and it is working fine now.
I run out of memory if I try to load SDCARD and Easyfile on with Extend.
I am using the SMALL option for Extend.
Is it possible to expand / use the memory from eeproms only to store / backup / compact to?
I have additional I2C EEPROMS
Even though the code is very compact the dictionary is not and can consume 10k so there is EEWORDS.fth that gets loaded sometime after EXTEND and the idea is to load your application last so add the filesystem functions and assuming you have 64k of EEPROM you can tell it to COMPACT the current dictionary into upper EEPROM. Thereafter you can load up your application normally with plenty of room to spare.
Once this is done you can still load and forget your application but if for some reason you need to change any of the compacted words you will need to do this from a cold start.
Key Features:
Propeller P8X32A-M44 chip
32 KB 24LC256-I/ST EEPROM
FTDI FT232RG and mini USB connector
USB data transfer indicator LEDs
5 MHz crystal in a removable socket
3.3 V, 500 mA voltage regulator
Reset pushbutton switch
Is it possible to use one of the other eeproms?
Parallax uses 64k EEPROMs these days but If you can consider replacing the EEPROM then don't worry about desoldering as if you were ever going to reuse the old chip again. I just gently press down on the pins with a craft knife so that the chip is removed then just run your iron over the pads to remove the pins, maybe with a blob of fresh solder or some flux. Best to press on the pin close to the chip body and brace your hand so that it doesn't want to jab into the pcb afterwards although this method is very safe and reliable and much better than desoldering or even trying to cut the pins (vs pressing).
btw, the 500ma figure for the regulator is practically useless, if you feed it from 5V that means at 500ma it would dissipate 1.7*0.5 = 850mW which is a lot of heat. The 500ma figure is probably only good for a 3.7V input. Never accept these figures for linear regs without taking power handling into consideration. Also I noticed the Propstick has the crystal in a socket which might be handy for the bench but please solder the crystal in if you intend to embed the Propstick.
I am using this for a robot and can not remove the existing serial hardware so would like to preferably add a second in / out to be live at the same time as the original console or redirect the original console.
I have this at the moment:
It works for the output for TF but not the input, any suggestions please?
Of course you could use SERIN but unfortunately it blocks while waiting for a character. I have been meaning to add some enhancements to Tachyon and more flexible serial I/O might be one of them.