eLua reference manual - MBED pio module
Overview
This module provide a function for accessing pin configuration features on the LPC17xx family of CPUs, and provides provides a pin mapping which corresponds to the pins and LEDs on the MBED platform. The pin configuration function allows the user to reconfigure pin function (as decribed in section 8.5 of the lpc17xx user manual, configure the pin as an open drain, and configure the pin as pullup, pulldown or tristate. Note that this module is a supplement of the platform independent pio module, not a replacement. Use this module only for setting up the MBED PIO pins, and the pio module for all the other PIO related operations. Below is a subset of available pin functions:
- PWM
MBED Pin ID Function LED1 1 FUNCTION_2 LED2 2 FUNCTION_2 LED3 3 FUNCTION_2 LED4 4 FUNCTION_2 p21 6 FUNCTION_1 p22 5 FUNCTION_1 p23 4 FUNCTION_1 p24 3 FUNCTION_1 p25 2 FUNCTION_1 p26 1 FUNCTION_1 - UART
MBED Pin ID Function p13 1 (TX) FUNCTION_1 p14 1 (RX) FUNCTION_1 p28 2 (TX) FUNCTION_1 p27 2 (RX) FUNCTION_1
In addition, this module provides pin mapping as found on the mbed board so that mbed.pio.p5 through mbed.pio.p30 map onto the mbed pins as described in the mbed handbook. LED pins are also usable, for example LED1 would correspond to mbed.pio.LED1.
Functions
mbed.pio.configpin( pin, function, mode, resistor)
Configure the pin.
Arguments:
- pin - the pin, as encoded in the pio or mbed.pio module.
- function - alternate pin function, Must be either mbed.pio.FUNCTION_0 (default), mbed.pio.FUNCTION_1, mbed.pio.FUNCTION_2, or mbed.pio.FUNCTION_3
- mode - open drain mode, can be either mbed.pio.MODE_DEFAULT (no open drain) or mbed.pio.MODE_OD (open drain).
- resistor - alternate pin function. Must be either mbed.pio.RES_PULLUP (default), mbed.pio.RES_TRISTATE, mbed.pio.RES_PULLDOWN.
Returns: nothing.