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Diffstat (limited to 'docs/esp8266/quickref.rst')
| -rw-r--r-- | docs/esp8266/quickref.rst | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/docs/esp8266/quickref.rst b/docs/esp8266/quickref.rst index 9c7db3205a..c884d93fc9 100644 --- a/docs/esp8266/quickref.rst +++ b/docs/esp8266/quickref.rst @@ -138,6 +138,45 @@ Also note that Pin(16) is a special pin (used for wakeup from deepsleep mode) and may be not available for use with higher-level classes like ``Neopixel``. +UART (serial bus) +----------------- + +See :ref:`machine.UART <machine.UART>`. :: + + from machine import UART + uart = UART(0, baudrate=9600) + uart.write('hello') + uart.read(5) # read up to 5 bytes + +Two UARTs are available. UART0 is on Pins 1 (TX) and 3 (RX). UART0 is +bidirectional, and by default is used for the REPL. UART1 is on Pins 2 +(TX) and 8 (RX) however Pin 8 is used to connect the flash chip, so +UART1 is TX only. + +When UART0 is attached to the REPL, all incoming chars on UART(0) go +straight to stdin so uart.read() will always return None. Use +sys.stdin.read() if it's needed to read characters from the UART(0) +while it's also used for the REPL (or detach, read, then reattach). +When detached the UART(0) can be used for other purposes. + +If there are no objects in any of the dupterm slots when the REPL is +started (on hard or soft reset) then UART(0) is automatically attached. +Without this, the only way to recover a board without a REPL would be to +completely erase and reflash (which would install the default boot.py which +attaches the REPL). + +To detach the REPL from UART0, use:: + + import uos + uos.dupterm(None, 1) + +The REPL is attached by default. If you have detached it, to reattach +it use:: + + import uos, machine + uart = machine.UART(0, 115200) + uos.dupterm(uart, 1) + PWM (pulse width modulation) ---------------------------- |