From b98197f950b572aff2a34934e64d094e5cea6cd5 Mon Sep 17 00:00:00 2001 From: Mike Causer Date: Fri, 30 Apr 2021 14:05:33 +1000 Subject: [PATCH] docs/esp32: Add UART to quickref. --- docs/esp32/quickref.rst | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/docs/esp32/quickref.rst b/docs/esp32/quickref.rst index c29688f000..2a9c8397c8 100644 --- a/docs/esp32/quickref.rst +++ b/docs/esp32/quickref.rst @@ -171,6 +171,33 @@ Notes: * The pull value of some pins can be set to ``Pin.PULL_HOLD`` to reduce power consumption during deepsleep. +UART (serial bus) +----------------- + +See :ref:`machine.UART `. :: + + from machine import UART + + uart1 = UART(1, baudrate=9600, tx=33, rx=32) + uart1.write('hello') # write 5 bytes + uart1.read(5) # read up to 5 bytes + +The ESP32 has three hardware UARTs: UART0, UART1 and UART2. +They each have default GPIO assigned to them, however depending on your +ESP32 variant and board, these pins may conflict with embedded flash, +onboard PSRAM or peripherals. + +Any GPIO can be used for hardware UARTs using the GPIO matrix, so to avoid +conflicts simply provide ``tx`` and ``rx`` pins when constructing. The default +pins listed below. + +===== ===== ===== ===== +\ UART0 UART1 UART2 +===== ===== ===== ===== +tx 1 10 17 +rx 3 9 16 +===== ===== ===== ===== + PWM (pulse width modulation) ----------------------------