74HC595 help
Hello All,
I had a program working nicely with the basic stamp2, and I reconstructed the project with the prop.
Everything was working with the prop and this serial output to a 7 segment display.
Then, I add the EMIC module and suddenly the 7 segment display doesn't work.
In the simple program included - see below - the first signal (%00000001)·should illuminate segment "A", but instead it illuminates segments "A" and "B".
The second binary signal (%00000010) should illuminate segment "B", but instead it jumps to segments "C" and "D".
The last binary signal (%00000100) illuminates segments "E" and "F" when it should illuminate segment "C".
This simple program just cycles through these three commands and then repeats itself.
I've used a pulldown (10k Ohm) on the latch output from the prop.
I've even connected a·470 Ohm resistor on each prop output pin - 0, 1 & 2.
The oscilliscope showed twice as many pulses as it did earlier when everything was working properly.
I'm scratching my head on this one because it worked so beautifully for a while then suddenly fell apart.
I was using the PE kit but that chip doesn't work any more, and now I'm using the demo kit.
One final note: when initially troubleshooting, I would send just one signal instead of three different signals, and the appropriate segment would light up.· However, when I sent a series of 3 different signals at 1 second intervals.··That's when things would get mixed up or "leapfrog".
Would anyone have any advice with this?
Much appreciated,
Shmow
·
I had a program working nicely with the basic stamp2, and I reconstructed the project with the prop.
Everything was working with the prop and this serial output to a 7 segment display.
Then, I add the EMIC module and suddenly the 7 segment display doesn't work.
In the simple program included - see below - the first signal (%00000001)·should illuminate segment "A", but instead it illuminates segments "A" and "B".
The second binary signal (%00000010) should illuminate segment "B", but instead it jumps to segments "C" and "D".
The last binary signal (%00000100) illuminates segments "E" and "F" when it should illuminate segment "C".
This simple program just cycles through these three commands and then repeats itself.
I've used a pulldown (10k Ohm) on the latch output from the prop.
I've even connected a·470 Ohm resistor on each prop output pin - 0, 1 & 2.
The oscilliscope showed twice as many pulses as it did earlier when everything was working properly.
I'm scratching my head on this one because it worked so beautifully for a while then suddenly fell apart.
I was using the PE kit but that chip doesn't work any more, and now I'm using the demo kit.
One final note: when initially troubleshooting, I would send just one signal instead of three different signals, and the appropriate segment would light up.· However, when I sent a series of 3 different signals at 1 second intervals.··That's when things would get mixed up or "leapfrog".
Would anyone have any advice with this?
{{PROP LED PROP 74HC595 ────────────── ──────────── ───────────── ────────────────────────────────────────────── 3.3V P 8 P 13 P 1 Data Out ─── P 14 Data In  │ │ P 0 Clock ─── P 11 Clock ┣──────┐ ┣─────┘ P 2 Latch ─┳─ P 12 Latch    │ P 10 P 16 GND  10 kΩ  GND ───────────────────────────────────────────────────────────────────────────────────────────────── SEVEN SEGMENT DISPLAY COMMON CATHODE 7 SEG 595 10 6 ─────── 100 Ω ───────  A  P10 (G) ── P6 │ │ P9 (F) ── P5 F B P7 (A) ── P15 │ │ P6 (B) ── P1 ── G ── P4 (C) ── P2 │ │ P2 (D) ── P3 E C P1 (E) ── P4 │ │ P3 ─── GND  D  P8 ─── GND 1 5 }} CON _clkmode = xtal1 + pll16x _xinfreq = 5_000_000 'Pin Assignments ClockPin = 0 SerialDataPin = 1 LatchPin = 2 VAR byte Pattern_10s OBJ BS2 : "BS2_Functions" ' Create BS2 Object PUB Main BS2.start (31,30) repeat 'GFEDCBA Pattern_10s := %00000001 BS2.SHIFTOUT(SerialDataPin, ClockPin, Pattern_10s, BS2#MSBFIRST, 8) '10's - 7 seg display BS2.PULSOUT(LatchPin,5) waitcnt(clkfreq+cnt) 'GFEDCBA Pattern_10s := %00000010 BS2.SHIFTOUT(SerialDataPin, ClockPin, Pattern_10s, BS2#MSBFIRST, 8) '10's - 7 seg display BS2.PULSOUT(LatchPin,5) waitcnt(clkfreq+cnt) 'GFEDCBA Pattern_10s := %00000100 BS2.SHIFTOUT(SerialDataPin, ClockPin, Pattern_10s, BS2#MSBFIRST, 8) '10's - 7 seg display BS2.PULSOUT(LatchPin,5) waitcnt(clkfreq+cnt)
Much appreciated,
Shmow
·