88 lines
2.4 KiB
C
88 lines
2.4 KiB
C
/** @file gpio.c
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* Module handling General Purpose Input/Output (GPIO) pins
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*
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* The module provides functions to configure the gpio pins and read from/
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* write to them
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*/
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//--includes--------------------------------------------------------------------
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#include "gpio.h"
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#include "gpio_regs.h"
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#include "rcc.h"
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//--local definitions-----------------------------------------------------------
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static volatile struct GPIO* regs = (struct GPIO*)GPIO_BASE_ADDRESS;
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//--local variables-------------------------------------------------------------
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//--public functions------------------------------------------------------------
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/**
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* Use the provided mask to generate its equivalent with 3 bits of padding
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* between each initial bit. This new mask matches the registers layout and
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* allow for direct application of the mode and config. Outputs are disabled
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* prior to confiiguration to avoid any glitches. The relevant clocks are
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* automatically enabled for the ports used
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*/
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void gpio_configure(enum GpioPort port, enum GpioPin pin_mask,
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enum GpioMode mode, enum GpioConfig config)
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{
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//ensure gpio port is enabled
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rcc_enable(RCC_AHB_NONE, RCC_APB1_NONE, RCC_APB2_IOPA << port);
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//reset outputs before configuring anything
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regs->PORTS[port].BRR.word = pin_mask;
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//clear config for selected port, then apply new config, 8 first pins
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uint32_t mask = 0;
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for (uint8_t i=0; i<8; ++i)
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{
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if (pin_mask & (0x1 << i))
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{
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mask |= 0x1 << (i * 4);
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}
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}
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regs->PORTS[port].CRL.word &= ~(0xF * mask);
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regs->PORTS[port].CRL.word |= (config << 2) | (mode << 0) * mask;
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//clear config for selected port, then apply new config, 8 last pins
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mask = 0;
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pin_mask = pin_mask >> 8;
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for (uint8_t i=0; i<8; ++i)
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{
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if (pin_mask & (0x1 << i))
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{
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mask |= 0x1 << (i * 4);
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}
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}
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regs->PORTS[port].CRH.word &= ~(0xF * mask);
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regs->PORTS[port].CRH.word |= (config << 2) | (mode << 0) * mask;
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}
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void gpio_reset(enum GpioPort port, enum GpioPin pin_mask)
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{
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gpio_configure(port, pin_mask, GPIO_MODE_INPUT, GPIO_CONFIG_IN_FLOATING);
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}
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void gpio_write(enum GpioPort port, enum GpioPin pin_mask, bool value)
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{
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if (value) {
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regs->PORTS[port].BSRR.word = pin_mask;
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} else {
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regs->PORTS[port].BRR.word = pin_mask;
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}
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}
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bool gpio_read(enum GpioPort port, enum GpioPin pin_mask)
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{
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return (regs->PORTS[port].IDR.word & pin_mask) == pin_mask;
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}
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//--local functions-------------------------------------------------------------
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