docs/rp2: Enhance quickref and change image to Pico pinout.

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NitiKaur 2021-07-10 13:35:52 +05:30 committed by Damien George
parent 0e3752e82a
commit da74ef6615
3 changed files with 53 additions and 41 deletions

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@ -3,7 +3,7 @@
Quick reference for the RP2
===========================
.. image:: img/rpipico.jpg
.. image:: img/pico_pinout.png
:alt: Raspberry Pi Pico
:width: 640px
@ -27,10 +27,9 @@ a troubleshooting subsection.
General board control
---------------------
The MicroPython REPL is on the USB serial port.
Tab-completion is useful to find out what methods an object has.
Paste mode (ctrl-E) is useful to paste a large slab of Python code into
the REPL.
The MicroPython REPL is accessed via the USB serial port. Tab-completion is useful to
find out what methods an object has. Paste mode (ctrl-E) is useful to paste a
large slab of Python code into the REPL.
The :mod:`machine` module::
@ -59,7 +58,19 @@ Use the :mod:`time <utime>` module::
Timers
------
How do they work?
RP2040's system timer peripheral provides a global microsecond timebase and
generates interrupts for it. The software timer is available currently,
and there are unlimited number of them (memory permitting). There is no need
to specify the timer id (id=-1 is supported at the moment) as it will default
to this.
Use the :mod:`machine.Timer` class::
from machine import Timer
tim = Timer(period=5000, mode=Timer.ONE_SHOT, callback=lambda t:print(1))
tim.init(period=2000, mode=Timer.PERIODIC, callback=lambda t:print(2))
.. _rp2_Pins_and_GPIO:
@ -84,19 +95,28 @@ Use the :ref:`machine.Pin <machine.Pin>` class::
UART (serial bus)
-----------------
There are two UARTs, UART0 and UART1. UART0 can be mapped to GPIO 0/1, 12/13
and 16/17, and UART1 to GPIO 4/5 and 8/9.
See :ref:`machine.UART <machine.UART>`. ::
from machine import UART
uart1 = UART(1, baudrate=9600, tx=33, rx=32)
from machine import UART, Pin
uart1 = UART(1, baudrate=9600, tx=Pin(4), rx=Pin(5))
uart1.write('hello') # write 5 bytes
uart1.read(5) # read up to 5 bytes
.. note::
REPL over UART is disabled by default. You can see the :ref:`rp2_intro` for
details on how to enable REPL over UART.
PWM (pulse width modulation)
----------------------------
How does PWM work on the RPi RP2xxx?
There are 8 independent channels each of which have 2 outputs making it 16
PWM channels in total which can be clocked from 7Hz to 125Mhz.
Use the ``machine.PWM`` class::
@ -112,14 +132,18 @@ Use the ``machine.PWM`` class::
ADC (analog to digital conversion)
----------------------------------
How does the ADC module work?
RP2040 has five ADC channels in total, four of which are 12-bit SAR based
ADCs: GP26, GP27, GP28 and GP29. The input signal for ADC0, ADC1, ADC2 and
ADC3 can be connected with GP26, GP27, GP28, GP29 respectively (On Pico board,
GP29 is connected to VSYS). The standard ADC range is 0-3.3V. The fifth
channel is connected to the in-built temperature sensor and can be used for
measuring the temperature.
Use the :ref:`machine.ADC <machine.ADC>` class::
from machine import ADC
adc = ADC(Pin(32)) # create ADC object on ADC pin
adc.read_u16() # read value, 0-65535 across voltage range 0.0v - 3.3v
from machine import ADC, Pin
adc = ADC(Pin(26)) # create ADC object on ADC pin
adc.read_u16() # read value, 0-65535 across voltage range 0.0v - 3.3v
Software SPI bus
----------------
@ -132,7 +156,7 @@ Software SPI (using bit-banging) works on all pins, and is accessed via the
# construct a SoftSPI bus on the given pins
# polarity is the idle state of SCK
# phase=0 means sample on the first edge of SCK, phase=1 means the second
spi = SoftSPI(baudrate=100000, polarity=1, phase=0, sck=Pin(0), mosi=Pin(2), miso=Pin(4))
spi = SoftSPI(baudrate=100_000, polarity=1, phase=0, sck=Pin(0), mosi=Pin(2), miso=Pin(4))
spi.init(baudrate=200000) # set the baudrate
@ -156,14 +180,15 @@ Software SPI (using bit-banging) works on all pins, and is accessed via the
Hardware SPI bus
----------------
Hardware SPI is accessed via the :ref:`machine.SPI <machine.SPI>` class and
has the same methods as software SPI above::
The RP2040 has 2 hardware SPI buses which is accessed via the
:ref:`machine.SPI <machine.SPI>` class and has the same methods as software
SPI above::
from machine import Pin, SPI
spi = SPI(1, 10000000)
spi = SPI(1, 10000000, sck=Pin(14), mosi=Pin(13), miso=Pin(12))
spi = SPI(2, baudrate=80000000, polarity=0, phase=0, bits=8, firstbit=0, sck=Pin(18), mosi=Pin(23), miso=Pin(19))
spi = SPI(1, 10_000_000) # Default assignment: sck=Pin(10), mosi=Pin(11), miso=Pin(8)
spi = SPI(1, 10_000_000, sck=Pin(14), mosi=Pin(15), miso=Pin(12))
spi = SPI(0, baudrate=80_000_000, polarity=0, phase=0, bits=8, sck=Pin(6), mosi=Pin(7), miso=Pin(4))
Software I2C bus
----------------
@ -173,7 +198,7 @@ accessed via the :ref:`machine.SoftI2C <machine.SoftI2C>` class::
from machine import Pin, SoftI2C
i2c = SoftI2C(scl=Pin(5), sda=Pin(4), freq=100000)
i2c = SoftI2C(scl=Pin(5), sda=Pin(4), freq=100_000)
i2c.scan() # scan for devices
@ -191,8 +216,8 @@ has the same methods as software I2C above::
from machine import Pin, I2C
i2c = I2C(0)
i2c = I2C(1, scl=Pin(5), sda=Pin(4), freq=400000)
i2c = I2C(0) # default assignment: scl=Pin(9), sda=Pin(8)
i2c = I2C(1, scl=Pin(3), sda=Pin(2), freq=400_000)
Real time clock (RTC)
---------------------
@ -202,13 +227,15 @@ See :ref:`machine.RTC <machine.RTC>` ::
from machine import RTC
rtc = RTC()
rtc.datetime((2017, 8, 23, 2, 12, 48, 0, 0)) # set a specific date and time
rtc.datetime((2017, 8, 23, 2, 12, 48, 0, 0)) # set a specific date and
# time, eg. 2017/8/23 1:12:48
rtc.datetime() # get date and time
WDT (Watchdog timer)
--------------------
Is there a watchdog timer?
The RP2040 has a watchdog which is a countdown timer that can restart
parts of the chip if it reaches zero.
See :ref:`machine.WDT <machine.WDT>`. ::
@ -218,21 +245,6 @@ See :ref:`machine.WDT <machine.WDT>`. ::
wdt = WDT(timeout=5000)
wdt.feed()
Deep-sleep mode
---------------
Is there deep-sleep support for the rp2?
The following code can be used to sleep, wake and check the reset cause::
import machine
# check if the device woke from a deep sleep
if machine.reset_cause() == machine.DEEPSLEEP_RESET:
print('woke from a deep sleep')
# put the device to sleep for 10 seconds
machine.deepsleep(10000)
OneWire driver
--------------