302 lines
8.7 KiB
C
302 lines
8.7 KiB
C
#include <stdio.h>
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#include <stm32f4xx.h>
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#include <stm32f4xx_rcc.h>
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#include <stm32f4xx_gpio.h>
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#include "misc.h"
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#include "mpconfig.h"
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#include "qstr.h"
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#include "systick.h"
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#include "obj.h"
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#include "runtime.h"
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#include "mma.h"
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#define MMA_ADDR (0x4c)
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void mma_init(void) {
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RCC->APB1ENR |= RCC_APB1ENR_I2C1EN; // enable I2C1
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//gpio_pin_init(GPIOB, 6 /* B6 is SCL */, 2 /* AF mode */, 1 /* open drain output */, 1 /* 25 MHz */, 0 /* no pull up or pull down */);
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//gpio_pin_init(GPIOB, 7 /* B7 is SDA */, 2 /* AF mode */, 1 /* open drain output */, 1 /* 25 MHz */, 0 /* no pull up or pull down */);
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//gpio_pin_af(GPIOB, 6, 4 /* AF 4 for I2C1 */);
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//gpio_pin_af(GPIOB, 7, 4 /* AF 4 for I2C1 */);
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// XXX untested GPIO init! (was above code)
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GPIO_InitTypeDef GPIO_InitStructure;
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// PB5 is connected to AVDD; pull high to enable MMA device
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GPIOB->BSRRH = GPIO_Pin_5; // PB5 low to start with
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GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
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GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
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GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
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GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
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GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
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GPIO_Init(GPIOB, &GPIO_InitStructure);
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// PB6=SCL, PB7=SDA
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GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
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GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
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GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;
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GPIO_InitStructure.GPIO_Speed = GPIO_Speed_25MHz;
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GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
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GPIO_Init(GPIOB, &GPIO_InitStructure);
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// alternate functions for SCL and SDA
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GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_I2C1);
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GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_I2C1);
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// get clock speeds
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RCC_ClocksTypeDef rcc_clocks;
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RCC_GetClocksFreq(&rcc_clocks);
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// disable the I2C peripheral before we configure it
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I2C1->CR1 &= ~I2C_CR1_PE;
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// program peripheral input clock
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I2C1->CR2 = 4; // no interrupts; 4 MHz (hopefully!) (could go up to 42MHz)
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// configure clock control reg
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uint32_t freq = rcc_clocks.PCLK1_Frequency / (100000 << 1); // want 100kHz, this is the formula for freq
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I2C1->CCR = freq; // standard mode (speed), freq calculated as above
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// configure rise time reg
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I2C1->TRISE = (rcc_clocks.PCLK1_Frequency / 1000000) + 1; // formula for trise, gives maximum rise time
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// enable the I2C peripheral
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I2C1->CR1 |= I2C_CR1_PE;
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// wait 20ms, then turn on AVDD, then wait 20ms again; this seems to work, but maybe can decrease delays
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// doesn't work for soft reboot; 50ms doesn't work either...
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sys_tick_delay_ms(20);
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GPIOB->BSRRL = GPIO_Pin_5;
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sys_tick_delay_ms(20);
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// set START bit in CR1 to generate a start cond!
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// init the chip via I2C commands
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mma_start(MMA_ADDR, 1);
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mma_send_byte(0);
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mma_stop();
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/*
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// read and print all 11 registers
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mma_start(MMA_ADDR, 1);
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mma_send_byte(0);
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mma_restart(MMA_ADDR, 0);
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for (int i = 0; i <= 0xa; i++) {
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int data;
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if (i == 0xa) {
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data = mma_read_nack();
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} else {
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data = mma_read_ack();
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}
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printf(" %02x", data);
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}
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printf("\n");
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*/
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// put into active mode
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mma_start(MMA_ADDR, 1);
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mma_send_byte(7); // mode
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mma_send_byte(1); // active mode
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mma_stop();
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/*
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// infinite loop to read values
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for (;;) {
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sys_tick_delay_ms(500);
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mma_start(MMA_ADDR, 1);
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mma_send_byte(0);
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mma_restart(MMA_ADDR, 0);
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for (int i = 0; i <= 3; i++) {
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int data;
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if (i == 3) {
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data = mma_read_nack();
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printf(" %02x\n", data);
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} else {
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data = mma_read_ack() & 0x3f;
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if (data & 0x20) {
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data |= ~0x1f;
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}
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printf(" % 2d", data);
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}
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}
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}
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*/
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}
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static uint32_t i2c_get_sr(void) {
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// must read SR1 first, then SR2, as the read can clear some flags
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uint32_t sr1 = I2C1->SR1;
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uint32_t sr2 = I2C1->SR2;
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return (sr2 << 16) | sr1;
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}
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void mma_restart(uint8_t addr, int write) {
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// send start condition
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I2C1->CR1 |= I2C_CR1_START;
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// wait for BUSY, MSL and SB --> Slave has acknowledged start condition
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uint32_t timeout = 1000000;
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while ((i2c_get_sr() & 0x00030001) != 0x00030001) {
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if (--timeout == 0) {
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printf("timeout in mma_restart\n");
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return;
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}
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}
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if (write) {
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// send address and write bit
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I2C1->DR = (addr << 1) | 0;
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// wait for BUSY, MSL, ADDR, TXE and TRA
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timeout = 1000000;
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while ((i2c_get_sr() & 0x00070082) != 0x00070082) {
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if (--timeout == 0) {
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printf("timeout in mma_restart write\n");
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return;
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}
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}
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} else {
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// send address and read bit
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I2C1->DR = (addr << 1) | 1;
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// wait for BUSY, MSL and ADDR flags
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timeout = 1000000;
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while ((i2c_get_sr() & 0x00030002) != 0x00030002) {
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if (--timeout == 0) {
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printf("timeout in mma_restart read\n");
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return;
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}
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}
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}
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}
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void mma_start(uint8_t addr, int write) {
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// wait until I2C is not busy
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uint32_t timeout = 1000000;
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while (I2C1->SR2 & I2C_SR2_BUSY) {
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if (--timeout == 0) {
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printf("timeout in mma_start\n");
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return;
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}
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}
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// do rest of start
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mma_restart(addr, write);
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}
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void mma_send_byte(uint8_t data) {
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// send byte
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I2C1->DR = data;
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// wait for TRA, BUSY, MSL, TXE and BTF (byte transmitted)
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uint32_t timeout = 1000000;
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while ((i2c_get_sr() & 0x00070084) != 0x00070084) {
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if (--timeout == 0) {
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printf("timeout in mma_send_byte\n");
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return;
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}
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}
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}
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uint8_t mma_read_ack(void) {
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// enable ACK of received byte
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I2C1->CR1 |= I2C_CR1_ACK;
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// wait for BUSY, MSL and RXNE (byte received)
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uint32_t timeout = 1000000;
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while ((i2c_get_sr() & 0x00030040) != 0x00030040) {
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if (--timeout == 0) {
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printf("timeout in mma_read_ack\n");
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break;
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}
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}
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// read and return data
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uint8_t data = I2C1->DR;
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return data;
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}
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uint8_t mma_read_nack(void) {
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// disable ACK of received byte (to indicate end of receiving)
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I2C1->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_ACK);
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// last byte should apparently also generate a stop condition
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I2C1->CR1 |= I2C_CR1_STOP;
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// wait for BUSY, MSL and RXNE (byte received)
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uint32_t timeout = 1000000;
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while ((i2c_get_sr() & 0x00030040) != 0x00030040) {
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if (--timeout == 0) {
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printf("timeout in mma_read_nack\n");
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break;
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}
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}
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// read and return data
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uint8_t data = I2C1->DR;
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return data;
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}
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void mma_stop(void) {
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// send stop condition
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I2C1->CR1 |= I2C_CR1_STOP;
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}
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/******************************************************************************/
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/* Micro Python bindings */
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int mma_buf[12];
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mp_obj_t pyb_mma_read(void) {
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for (int i = 0; i <= 6; i += 3) {
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mma_buf[0 + i] = mma_buf[0 + i + 3];
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mma_buf[1 + i] = mma_buf[1 + i + 3];
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mma_buf[2 + i] = mma_buf[2 + i + 3];
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}
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mma_start(MMA_ADDR, 1);
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mma_send_byte(0);
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mma_restart(MMA_ADDR, 0);
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for (int i = 0; i <= 2; i++) {
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int v = mma_read_ack() & 0x3f;
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if (v & 0x20) {
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v |= ~0x1f;
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}
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mma_buf[9 + i] = v;
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}
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int jolt_info = mma_read_nack();
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mp_obj_t data[4];
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data[0] = mp_obj_new_int(jolt_info);
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data[1] = mp_obj_new_int(mma_buf[2] + mma_buf[5] + mma_buf[8] + mma_buf[11]);
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data[2] = mp_obj_new_int(mma_buf[1] + mma_buf[4] + mma_buf[7] + mma_buf[10]);
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data[3] = mp_obj_new_int(mma_buf[0] + mma_buf[3] + mma_buf[6] + mma_buf[9]);
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return rt_build_tuple(4, data); // items in reverse order in data
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}
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MP_DEFINE_CONST_FUN_OBJ_0(pyb_mma_read_obj, pyb_mma_read);
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mp_obj_t pyb_mma_read_all(void) {
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mp_obj_t data[11];
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mma_start(MMA_ADDR, 1);
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mma_send_byte(0);
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mma_restart(MMA_ADDR, 0);
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for (int i = 0; i <= 9; i++) {
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data[10 - i] = mp_obj_new_int(mma_read_ack());
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}
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data[0] = mp_obj_new_int(mma_read_nack());
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return rt_build_tuple(11, data); // items in reverse order in data
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}
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MP_DEFINE_CONST_FUN_OBJ_0(pyb_mma_read_all_obj, pyb_mma_read_all);
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mp_obj_t pyb_mma_write_mode(mp_obj_t o_int, mp_obj_t o_mode) {
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mma_start(MMA_ADDR, 1);
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mma_send_byte(6); // start at int
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mma_send_byte(mp_obj_get_int(o_int));
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mma_send_byte(mp_obj_get_int(o_mode));
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mma_stop();
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return mp_const_none;
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}
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MP_DEFINE_CONST_FUN_OBJ_2(pyb_mma_write_mode_obj, pyb_mma_write_mode);
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