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UNSTABLE-irq-example.py
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UNSTABLE-irq-example.py
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# Measure edge timing on Pin1, and also pin states Pin1,Pin2
# MicroPython for Raspberry Pi Pico (RP2040)
# J.Beale 22-MAR-2021
""" _______ _______
P1 ______/ \_______/ \______
_______ _______ __
P2 __/ \_______/ \_______/
A B C D E F
Time P1 edges (B-D, D-F) with a resolution of 2 * Tclock (8 ns @ F=250MHz)
also record (P1,P2) levels at 2..4 cycles after each P1 edge
For debug, connect GP22 -> GP17 and GP21 -> GP16
GP## numbering as per RasPi Pico pinout on p.4 of
https://datasheets.raspberrypi.org/pico/pico-datasheet.pdf
"""
import rp2 # rp2.PIO, rp2.asm_pio
import machine as m # m.freq, m.Pin
import utime # utime.sleep
#MFREQ = 250000000 # CPU frequency in Hz (typ. 125 MHz; Overclock to 250 MHz)
MFREQ = 125000000 # CPU frequency in Hz (typ. 125 MHz; Overclock to 250 MHz)
# ------------------------------------------------------------
@rp2.asm_pio()
def pin_timing():
# mov(x,0) # init could be done with _sm.exec() from caller
# wait(0,pin,0) # wait for pin1 to be low (if isn't already)
# wait(1,pin,0) # wait for pin1 to be high: first rising edge
# jmp(x_dec,'loop1') # start main loop
wrap_target()
# ===== now pin1 is high. Dec X, exit when pin1 goes low
label('loop1')
jmp(x_dec,'continue') # decrement X, jump if zero
label('continue')
jmp(pin, 'loop1') # jump when pin1 is high
# ==== send out two words: (X counter value, state of Pin1, Pin2 )
mov(isr,x) # transfer X to input shift register
push() # transfer shift register to FIFO
in_(pins, 2) # read two bits (Pin1,Pin2) into ISR
push() # send them to FIFO (also zeroing ISR)
irq(0) # signal data ready
# ===== now pin1 is low. Dec x, exit when pin1 goes high
label('loop2')
jmp(pin, 'exit') # jump when pin1 is high
jmp(x_dec,'loop2') # decrement X, jump if zero
jmp('loop2') # keep going, if it rolls over
label('exit')
# ==== send out two words: (X counter value, state of Pin1, Pin2 )
mov(isr,x) # transfer X to input shift register
push() # transfer shift register to FIFO
in_(pins, 2) # read two bits (Pin1,Pin2) into ISR
push() # send them to FIFO (also zeroing ISR)
irq(0) # signal data ready
wrap()
# ---------------------------------------------------------------------
def irqHandler(sm):
global timeData,pinData,newDataFlag,pulsein
(timeData,pinData) = pulsein.read() # get the new values
newDataFlag = True
#print(pio.irq().flags())
def irqHandler2(sm):
global timeData,pinData,newDataFlag,pulsein2
(timeData,pinData) = pulsein2.read() # get the new values
newDataFlag = True
# ---------------------------------------------------------------------
class pulseTimer:
# Instantiate StateMachine(0) with PIO program on Pin(16).
def __init__(self, pin1, stateMachine=0):
self.pin1 = pin1
self.sm = stateMachine
def read_blocking(self, n):
''' in_base declares the first Pin offset
jmp_pin declares the one pin used for jmp (not an offset)
'''
data = []
# Each list element is tuple: (X reg timer, PIO pin states)
for i in range(n):
data.append( (0xffffffff-self.sm.get(),self.sm.get()) )
return data
def read(self):
''' in_base declares the first Pin offset
jmp_pin declares the one pin used for jmp (not an offset)
'''
# Return tuple: (X reg timer, PIO pin states)
return ( (0xffffffff-self.sm.get(),self.sm.get()) )
# -----------------------------------------
def vBlink(p,t,n): # blink LED on pin p, duration t milliseconds, repeat n times
for i in range(n):
p.value(1)
utime.sleep_ms(t)
p.value(0) # Pico, ESP32: 0 means LED off
utime.sleep_ms(t)
# -----------------------------------------
def tickT1(timer): # timer callback to blink ext. LED
global led2
led2.toggle()
#print("A:%d" % utime.ticks_ms())
def tickT2(timer): # timer callback to blink ext. LED
global led3, led1
led1.toggle()
led3.toggle()
#print("B:%d" % utime.ticks_ms())
# -----------------------------------------
def main():
global led1,led2,led3
global timeData,pinData,newDataFlag
global pulsein
m.freq(MFREQ) # set CPU frequency; not necessarily the default 125 MHz
newDataFlag = False # haven't got any new data yet
led1 = m.Pin(25, m.Pin.OUT) # set pin 25 (driving onboard LED) to output
led2 = m.Pin(22, m.Pin.OUT) # set external output pin (driving offboard LED) to output
led3 = m.Pin(21, m.Pin.OUT) # set external output pin (driving offboard LED) to output
led1.off()
led2.off()
led3.off()
vBlink(led1,150,3) # program-starting signal from onboard LED
utime.sleep_ms(500)
p1 = m.Pin(16,m.Pin.IN, m.Pin.PULL_UP) # Channel A / Pin1 input
p2 = m.Pin(17,m.Pin.IN, m.Pin.PULL_UP) # Channel B / Pin2 input
sm0 = rp2.StateMachine(0, pin_timing, in_base=p1)
#sm1 = rp2.StateMachine(1, pin_timing, in_base=p1)
pulsein = pulseTimer(p1,sm0) # timer to look for ChA signals
#pulsein2 = pulseTimer(p1,sm1) # timer to look for ChB signals
sm0.init(pin_timing,freq=MFREQ,in_base=(p1),jmp_pin=(p1))
#sm1.init(pin_timing,freq=MFREQ,in_base=(p1),jmp_pin=(p2))
sm0.irq(irqHandler)
#sm1.irq(irqHandler2)
sm0.exec("mov(x,0)") # init X register before running
#sm1.exec("mov(x,0)") # init X register before running
sm0.active(1) # start state machines running here
#sm1.active(1) # start state machines running here
# when PIO #0 generates interrupt, load the data from FIFO into global vars
#rp2.PIO(0).irq( doIRQ0() )
# ------------------- testing: simulate quadrature signal on output pins
tim1 = m.Timer()
tim2 = m.Timer()
tim1.init(freq=1, mode=m.Timer.PERIODIC, callback=tickT1) # blink at this rate
utime.sleep_ms(500)
tim2.init(freq=1, mode=m.Timer.PERIODIC, callback=tickT2) # blink at this rate
# --------------------------
edges = 1 # how many edges to get at one time
lcount = 0 # how many lines total sent
pcount = 0 # how many packets sent (printed)
maxTimerCount = 1<<32 # 32 bit counter rolls over here 2^32 = 4,294,967,296
#(oldTicks,oldPins) = pulsein.read_blocking(1)[0] # first call sets previous values
print("Now waiting for new data flag.")
while True: # wait for new data to arrive in background via interrupt
if newDataFlag:
break
print("Got flag.")
(oldTicks,oldPins) = (timeData, pinData)
newDataFlag = False # reset to prepare for next data
oldPins = oldPins << 2
# --------- Main Loop -----------------------------------------
while True: # main loop
if newDataFlag:
(n,pVal) = (timeData, pinData)
newDataFlag = False # reset flag for next time
lcount += 1
i = 0
outs = ("%d," % lcount)
ticks = (n + 2*i) # +2*i correction from (mov,push,in,push) overhead
delta = (ticks - oldTicks) % maxTimerCount
# outs += ("%d" % delta) + "," + '{0:d},{0:02b}'.format(delta,pVal)
pVals = (oldPins & 0b1100) | (pVal & 0b0011)
#outs += '{0:d},{1:04b}'.format(delta,pVals)
outs += '{0:02d},{1:04b},{2:d}'.format(pVals,pVals,delta)
oldTicks = ticks
oldPins = pVal << 2
i += 1
if i != edges:
outs += ","
# outs += str(oldTicks)
oldTicks = (oldTicks - 2*i) % maxTimerCount
outs += '\n' # end of line char concludes each line
# uart.write(outs)
print(outs,end='')
pcount += 1
# --------- End Main Loop -----------------------------------------
"""
p.392 https://datasheets.raspberrypi.org/rp2040/rp2040-datasheet.pdf
Write Register IO:CTRL Register:SM_ENABLE set the enable bits (3..0) which starts the respective state machines.
0x03 would start both SM 0 and SM 1 at the same time.
"""
# ------------------------------
main()