101 lines
2.7 KiB
C
101 lines
2.7 KiB
C
/*
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* Copyright (c) 2021 Valentin Milea <valentin.milea@gmail.com>
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*
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* SPDX-License-Identifier: MIT
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*/
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#include "include/i2c_slave.h"
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#include <pico/stdlib.h>
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#include <hardware/irq.h>
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#include "include/i2c_buffer.h"
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static bool transfer_in_progress;
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static inline void finish_transfer(void)
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{
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if(transfer_in_progress)
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{
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i2c_slave_buffer_handler(I2C_SLAVE_FINISH);
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transfer_in_progress = false;
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}
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}
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static void __not_in_flash_func(i2c_slave_irq_handler)(void)
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{
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i2c_hw_t *hw = i2c_get_hw(I2C_SLAVE_INSTANCE);
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uint32_t intr_stat = hw->intr_stat;
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if(intr_stat == 0)
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{
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return;
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}
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if(intr_stat & I2C_IC_INTR_STAT_R_TX_ABRT_BITS)
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{
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hw->clr_tx_abrt;
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finish_transfer();
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}
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if(intr_stat & I2C_IC_INTR_STAT_R_START_DET_BITS)
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{
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hw->clr_start_det;
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finish_transfer();
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}
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if(intr_stat & I2C_IC_INTR_STAT_R_STOP_DET_BITS)
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{
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hw->clr_stop_det;
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finish_transfer();
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}
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if(intr_stat & I2C_IC_INTR_STAT_R_RX_FULL_BITS)
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{
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transfer_in_progress = true;
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i2c_slave_buffer_handler(I2C_SLAVE_RECEIVE);
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}
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if(intr_stat & I2C_IC_INTR_STAT_R_RD_REQ_BITS)
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{
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hw->clr_rd_req;
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transfer_in_progress = true;
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i2c_slave_buffer_handler(I2C_SLAVE_REQUEST);
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}
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}
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void i2c_slave_init(void)
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{
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// Init GPIO pins
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gpio_set_function(I2C_SLAVE_SDA_PIN, GPIO_FUNC_I2C);
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gpio_set_function(I2C_SLAVE_SCL_PIN, GPIO_FUNC_I2C);
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// Note: The I2C slave does clock stretching implicitly after a RD_REQ, while the Tx FIFO is empty.
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// There is also an option to enable clock stretching while the Rx FIFO is full, but we leave it
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// disabled since the Rx FIFO should never fill up (unless i2c_slave.handler() is way too slow).
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i2c_set_slave_mode(I2C_SLAVE_INSTANCE, true, I2C_SLAVE_ADDRESS);
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i2c_hw_t *hw = i2c_get_hw(I2C_SLAVE_INSTANCE);
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// unmask necessary interrupts
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hw->intr_mask = I2C_IC_INTR_MASK_M_RX_FULL_BITS | I2C_IC_INTR_MASK_M_RD_REQ_BITS | I2C_IC_RAW_INTR_STAT_TX_ABRT_BITS | I2C_IC_INTR_MASK_M_STOP_DET_BITS | I2C_IC_INTR_MASK_M_START_DET_BITS;
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// enable interrupt for current core
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uint num = I2C0_IRQ + i2c_get_index(I2C_SLAVE_INSTANCE);
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irq_set_exclusive_handler(num, i2c_slave_irq_handler);
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irq_set_enabled(num, true);
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}
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void i2c_slave_deinit(void)
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{
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uint num = I2C0_IRQ + i2c_get_index(I2C_SLAVE_INSTANCE);
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irq_set_enabled(num, false);
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irq_remove_handler(num, i2c_slave_irq_handler);
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i2c_set_slave_mode(I2C_SLAVE_INSTANCE, false, 0);
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transfer_in_progress = false;
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i2c_hw_t *hw = i2c_get_hw(I2C_SLAVE_INSTANCE);
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hw->intr_mask = I2C_IC_INTR_MASK_RESET;
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}
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