Differences
This shows you the differences between two versions of the page.
| Both sides previous revision Previous revision | Next revision Both sides next revision | ||
|
raspberrypipico:raspberrypipico [2021/03/12 13:10] admin [Programmable I/O] |
raspberrypipico:raspberrypipico [2021/03/12 13:21] admin [Programmable I/O] |
||
|---|---|---|---|
| Line 107: | Line 107: | ||
| ==== Programmable I/O ==== | ==== Programmable I/O ==== | ||
| [[raspberrypipico: | [[raspberrypipico: | ||
| - | |||
| - | ---- | ||
| - | [[https:// | ||
| - | The RP Pico has eight state machines (0-7) including these parameters: | ||
| - | - state machine number\\ | ||
| - | - PIO program\\ | ||
| - | - frequency (between 2000 and 125000000)\\ | ||
| - | - GPIO pin\\ | ||
| - | These mini programs run on the PIO state machines and run continuously.\\ | ||
| - | |||
| - | from rp2 import PIO, StateMachine, | ||
| - | from machine import Pin | ||
| - | import utime | ||
| - | | ||
| - | led_onboard = machine.Pin(25, | ||
| - | led_onboard.value(1) | ||
| - | utime.sleep(2) | ||
| - | led_onboard.value(0) | ||
| - | | ||
| - | @asm_pio(set_init=PIO.OUT_LOW) | ||
| - | def faint_led(): | ||
| - | set(pins, 0) [20] | ||
| - | set(pins, 1) | ||
| - | | ||
| - | sm1 = StateMachine(1, | ||
| - | | ||
| - | while(True): | ||
| - | sm1.active(1) | ||
| - | utime.sleep(1) | ||
| - | sm1.active(0) | ||
| - | utime.sleep(1) | ||
| - | |||
| - | The commands set(pins, 0) and set(pins, 1) turns the GPIO pin on and off.\\ | ||
| - | In square brackets are numbers between 1 and 31 to pause this clock cycles\\ | ||
| - | The @asm_pio descriptor above the function takes the set_init parameters.\\ | ||
| - | To start and stop the state machine use the active method (1 or 0)\\ | ||
| - | |||
| - | ==The Nine State Machine Instructions== | ||
| - | * in – Shifts 1 word of 32 bits at a time into the ISR | ||
| - | * out – Shifts 1 word of 32 bits from the OSR e.g. out(pins, 4) | ||
| - | * push – Sends data to the RX (input) | ||
| - | * pull() – gets data from the TX (output), | ||
| - | * mov() – moves data x or y in register, e.g. mov(y, osr) osr=output shift register | ||
| - | * irq – Sets or clears interrupt flag e.g. irq(rel(0)) in python: sm.irq(myFunction) | ||
| - | * set() [] – Writes data to destination, | ||
| - | * wait – Pauses until a defined action happens | ||
| - | * label(" | ||
| - | ==Some more Instructions== | ||
| - | - nop () [] - no operations, delays 0 to 31 circles\\ | ||
| - | - wrap_target() and wrap () - resets program counter and starts over again\\ | ||
| - | - lable() - sts a lable label(" | ||
| - | - jmp () - jumps conditions: | ||
| - | _ jump if zero: jmp(not_x, " | ||
| - | _ shift the register, jump if not exhausted: jmp(not_osre, | ||
| - | _ decrements, jump if not zero: jmp(x_dec," | ||
| - | |||
| - | Example by [[https:// | ||
| - | ]] and on [[https:// | ||
| - | |||
| - | [[https:// | ||
| - | |||
| - | [[https:// | ||
| ---- | ---- | ||