From Newsgroup: comp.sys.raspberry-pi

Hi, i have this code hos do i calculate the frquency and pulse width?

from machine import Pin
from rp2 import PIO, StateMachine, asm_pio
import time

led = Pin("LED", Pin.OUT, value=0)

@asm_pio(set_init=PIO.OUT_LOW)
def square():
# Cycles: 1 + 1 + 6 + 32 * (30 + 1) = 1000
irq(rel(0))
set(pins, 1)
set(x, 31) [5]
label("delay_high")
nop() [5]
jmp(x_dec, "delay_high")

# Cycles: 1 + 7 + 32 * (30 + 1) = 1000
set(pins, 0)
set(x, 31) [5]
label("delay_low")
nop() [1]
jmp(x_dec, "delay_low")

sm = StateMachine(0, square, freq=2000, set_base=Pin(0))

sm.irq(lambda p: led.toggle())

sm.active(1)


--- Synchronet 3.20a-Linux NewsLink 1.114

From Newsgroup: comp.sys.raspberry-pi

On Fri, 1 Nov 2024 07:19:07 +0100, Samson wrote:

[how] do i calculate the frquency and pulse width?

Let’s see, cycle duration = 1 ÷ frequency, so pulse width must be duty cycle × cycle duration.

What do I win?
--- Synchronet 3.20a-Linux NewsLink 1.114

From Newsgroup: comp.sys.raspberry-pi

Den 01-11-2024 kl. 22:03 skrev Lawrence D'Oliveiro:

On Fri, 1 Nov 2024 07:19:07 +0100, Samson wrote:

[how] do i calculate the frquency and pulse width?

Let’s see, cycle duration = 1 ÷ frequency, so pulse width must be duty cycle × cycle duration.

What do I win?

Sorry here are more info. The pico limits PWM 8 Hz and up pulse width 1 - 100 % .
I have this program and i works i understand how it works.


my problem was understanding >> dup[delay] ?

=====
# Example using PIO to blink an LED and raise an IRQ at 1Hz.

import time
from machine import Pin
import rp2


@rp2.asm_pio(set_init=rp2.PIO.OUT_LOW)
def blink_1hz():
# Cycles: 1 + 1 + 6 + 32 * (30 + 1) = 1000
irq(rel(0))
set(pins, 1)
set(x, 31) [5]
label("delay_high")
nop() [29]
jmp(x_dec, "delay_high")

# Cycles: 1 + 7 + 32 * (30 + 1) = 1000
set(pins, 0)
set(x, 31) [6]
label("delay_low")
nop() [29]
jmp(x_dec, "delay_low")


# Create the StateMachine with the blink_1hz program, outputting on Pin(25).
sm = rp2.StateMachine(0, blink_1hz, freq=2000, set_base=Pin(25))

# Set the IRQ handler to print the millisecond timestamp.
sm.irq(lambda p: print(time.ticks_ms()))

# Start the StateMachine.
sm.active(1)

--- Synchronet 3.20a-Linux NewsLink 1.114