POSEDGE detection code.
StephenMoore
Posts: 188
I am trying to measure the number of pulses coming into pina between the toggling of pinb.
I want to continuously read out the pulse total in a separate cog. Here is the scenario:
I am passing the address of my display variable in countAddr when I call Start(countAddr, pulsePin, disablePin). However, the code fails and I can not figure out why.
Any suggestions would be welcome.
Sincerely,
sm
I want to continuously read out the pulse total in a separate cog. Here is the scenario:
''Counter used as a pulse counter
CON
POSEDGE = 0100000
PUB Start(countAddr, pulsePin, disablePin)
pina := pulsePin
pinb := disablePin
cognew(@entry, countAddr)
DAT
org
entry mov frqa, #1 'increment for each edge seen
movs ctra, pina 'setup encoder pin
movi ctra, ctra_ 'establish mode and start counter
:loop test ina, pinb wz 'check state of stepper drive enable pin
if_z jmp #:loop
mov phsa, #0 'zero out pulse counter
:count test ina, pinb wz
wrlong phsa, par 'send the current value back
if_nz jmp #:count
jmp #:loop
ctra_ long POSEDGE<< 26 'mode
pina long 1
pinb long 1
addr res 1
I am passing the address of my display variable in countAddr when I call Start(countAddr, pulsePin, disablePin). However, the code fails and I can not figure out why.
Any suggestions would be welcome.
Sincerely,
sm
Comments
-Phil
Here is a corrected (but untested) version. For sure you need to pass some values to the Start methode to try it.
''Counter used as a pulse counter CON POSEDGE = %01010_000 PUB Start(countAddr, pulsePin, disablePin) pina := pulsePin pinb := disablePin maskb := 1<<disablePin cognew(@entry, countAddr) DAT org 0 entry mov frqa, #1 'increment for each edge seen movs ctra, pina 'setup encoder pin movi ctra, #POSEDGE 'establish mode and start counter :loop test maskb, ina wz 'check state of stepper drive enable pin if_z jmp #:loop mov phsa, #0 'zero out pulse counter :count test maskb, ina wz if_nz jmp #:count wrlong phsa, par 'write the measured value jmp #:loop pina long 0 pinb long 0 maskb long 0 addr res 1Andy
The code still doesn't update the phsa value with the pulse inputs from pina so I added some debug features.
''Counter used as a pulse counter CON POSEDGE = 010000 VAR long value PUB Start(countAddr, pulsePin, disablePin) 'pina := pulsePin led := 8 pina := 9 pinb := disablePin maskb := 1 << pinb maskled := 1 << led cognew(@entry, countAddr) DAT org entry or dira, maskled mov frqa, #1 'increment for each edge seen movs ctra, pina 'setup encoder pin movi ctra, #POSEDGE 'establish mode and start counter :loop test maskb, ina wz 'check state of stepper drive enable pin (pinb goes low to start) if_z jmp #:loop mov phsa, #0 'zero out pulse counter mov time, cnt add time, delay :count test maskb, ina wz xor outa, maskled waitcnt time, delay wrlong phsa, par 'send the current value back if_nz jmp #:count jmp #:loop pina long 0 pinb long 0 maskb long 0 delay long $400000 led long 0 maskled long 0 time res 1Other than that the logic seems ok. That is pinb On/Off starts the led blinking but the posedge counter does not count the led pusles.
The wrlong works fine as I can read and display from the calling cog values I force into the phsa register.
I appreciate your help and am a little concerned why after all the effort I put into learning PASM very little of it sticks with me.
Sincerely,
sm
pina, in this case, evaluates to 512, which is not a valid pin number.
-Phil
The program is supposed to pulse pin 8 (led) which is used to provide input to pin 9 (pina), which it does. The counter is supposed to simply count the pulse leading edges and write the number out continuously, which it does not.
''Counter used as a pulse counter CON POSEDGE = 010000 PUB Start(countAddr, pulsePin, disablePin) 'pina := pulsePin led := 8 pina := led + 1 pinb := disablePin maskb := 1 << pinb maskled := 1 << led cognew(@entry, countAddr) DAT org entry or dira, maskled movs ctra, pina 'setup encoder pin movi ctra, #POSEDGE 'establish mode and start counter mov frqa, #1 'increment for each edge seen :loop test maskb, ina wz 'check state of stepper drive enable pin (pinb goes low to start) if_z jmp #:loop mov phsa, #0 'zero out pulse counter mov time, cnt add time, delay :count test maskb, ina wz xor outa, maskled waitcnt time, delay wrlong phsa, par 'send the current value back if_nz jmp #:count jmp #:loop pina long 0 pinb long 0 maskb long 0 delay long $400000 led long 0 maskled long 0 time res 1I hope that your Memorial Day is a good one.
The following code works on my Quickstart board. It has a testcode which calls the Start methode and generates some test patterns at the pins:
CON _clkmode = xtal1 + pll16x _xinfreq = 5_000_000 OBJ ser : "FullDuplexSerial" VAR long value PUB Main ser.start(31,30,0,115200) Start(@value, 0, 1) 'clock at pin0, disable at pin 1 ctra := %00100<<26 + 0 frqa := 1<<31 / (clkfreq/2000) 'output testclock 1000Hz at pin 0 dira[1..0] := %11 repeat outa[1] := 1 waitcnt(clkfreq/10 + cnt) 'enable 100ms outa[1] := 0 ser.dec(value) ser.tx(13) outa[1] := 1 waitcnt(clkfreq + cnt) 'enable 1s outa[1] := 0 ser.dec(value) ser.tx(13) ''Counter used as a pulse counter CON POSEDGE = %01010_000 PUB Start(countAddr, pulsePin, disablePin) pina := pulsePin pinb := disablePin maskb := 1<<disablePin cognew(@entry, countAddr) DAT org 0 entry mov frqa, #1 'increment for each edge seen movs ctra, pina 'setup encoder pin movi ctra, #POSEDGE 'establish mode and start counter :loop test maskb, ina wz 'check state of stepper drive enable pin if_z jmp #:loop mov phsa, #0 'zero out pulse counter :count test maskb, ina wz if_nz jmp #:count mov phsa, phsa 'copy phsa to shadow register wrlong phsa, par 'write the measured value jmp #:loop pina long 0 pinb long 0 maskb long 0 ledmsk long 1<<16Andy
That's it. I can not express to you how many times I have gone over this code and failed to make it work right. This business of shadow registers is covered only vaguely in the manual.
I thank you sir for your help. And thanks to Mr. Pilgrim for looking at too.
I wish there were a way to payback but I always seem to be on the receiving end.
Regards,
sm