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81 lines
1.7 KiB
C
81 lines
1.7 KiB
C
/*
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* Copyright (C) 2018 Bas Stottelaar <basstottelaar@gmail.com>
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @ingroup boards_common_silabs_drivers_pic
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* @{
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*
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* @file
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* @brief Implementations of the power-and-interrupt controller.
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*
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* @author Bas Stottelaar <basstottelaar@gmail.com>
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*
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* @}
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*/
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#include "pic.h"
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#include "periph/gpio.h"
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#include "periph/i2c.h"
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/**
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* @brief Ensure the interrupt wake pin is defined.
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*/
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#ifndef PIC_INT_WAKE_PIN
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#error "PIC_I2C_WAKE_PIN is not defined by the board."
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#endif
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/**
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* @brief Ensure the PIC I2C device is defined.
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*/
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#ifndef PIC_I2C
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#error "PIC_I2C is not defined by the board."
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#endif
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/**
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* @brief Ensure the I2C address of the PIC is defined.
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*/
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#ifndef PIC_I2C_ADDR
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#error "PIC_I2C_ADDR is not defined by the board."
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#endif
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/**
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* @brief Microsecond sleep method, which does not rely on xtimer.
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*
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* @param[in] delay Amount of microseconds to delay.
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*/
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static inline void _usleep(uint32_t delay)
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{
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/* decrement + compare take two cycles, therefore divide by two */
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uint32_t count = (delay * (SystemCoreClock / 1000 / 1000)) / 2;
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while (count--) {}
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}
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void pic_init(void)
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{
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gpio_init(PIC_INT_WAKE_PIN, GPIO_OD);
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gpio_set(PIC_INT_WAKE_PIN);
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}
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void pic_write(uint8_t addr, uint8_t value)
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{
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/* toggle the pin for 4 us */
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gpio_clear(PIC_INT_WAKE_PIN);
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_usleep(4);
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/* write to gpio expander */
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i2c_acquire(PIC_I2C);
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uint8_t bytes[] = { addr, value };
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i2c_write_bytes(PIC_I2C, PIC_I2C_ADDR, bytes, 2, 0);
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i2c_release(PIC_I2C);
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/* put PIC in sleep mode again */
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gpio_set(PIC_INT_WAKE_PIN);
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}
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