i2c-master: start extracting out i2c code

Working on f4 with an external sht21 i2c sensor.
Still lots of f4 specifics yet.  But, progress.

1 files changed, 183 insertions, 2 deletions

diff --git a/tests/i2c-master/i2c-master.c b/tests/i2c-master/i2c-master.c
index 64c9cfe..2c8e604 100644
--- a/tests/i2c-master/i2c-master.c
+++ b/tests/i2c-master/i2c-master.c
@@ -2,22 +2,203 @@
  * Feb 2017, Karl Palsson <karlp@tweak.net.au>
  */
 
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
 #include <libopencm3/stm32/i2c.h>
 #include <libopencm3/stm32/rcc.h>
+#include "trace.h"
 #include "hw.h"
 #include "i2c-master.h"
 
+#define SENSOR_ADDRESS (0x40)
 
-void i2cm_init(void) {
+enum sht21_cmd_e {
+	SHT21_CMD_TEMP_HOLD = 0xe3,
+	SHT21_CMD_HUMIDITY_HOLD = 0xe5,
+	SHT21_CMD_TEMP_NOHOLD = 0xf3,
+	SHT21_CMD_HUMIDITY_NOHOLD = 0xf5,
+	SHT21_CMD_WRITE_REG = 0xe6,
+	SHT21_CMD_READ_REG = 0xe7,
+	SHT21_CMD_RESET = 0xfe,
+	/* 0xfa, 0x0f to read serial */
+};
+
+void i2cm_init(void)
+{
 	rcc_periph_clock_enable(hw_details.periph_rcc);
 	rcc_periph_reset_pulse(hw_details.periph_rst);
 	i2c_set_standard_mode(hw_details.periph);
-	i2c_enable_ack(hw_details.periph);
+	//	i2c_enable_ack(hw_details.periph); /* NO ACK FOR SHT21! */
 	//i2c_set_dutycycle(hw_details.periph, I2C_CCR_DUTY_DIV2); /* default, no need to do this really */
+
+	/* --------- board specific settings!  */
 	i2c_set_clock_frequency(hw_details.periph, I2C_CR2_FREQ_42MHZ);
 	/* 42MHz / (100kHz * 2) */
 	i2c_set_ccr(hw_details.periph, 210);
 	/* standard mode, freqMhz+1*/
 	i2c_set_trise(hw_details.periph, 43);
+	/* --------- end of board specific settings!*/
+
 	i2c_peripheral_enable(hw_details.periph);
+}
+
+static void sht21_send_data(uint32_t i2c, size_t n, uint8_t *data)
+{
+	while ((I2C_SR2(i2c) & I2C_SR2_BUSY)) {
+	}
+
+	i2c_send_start(i2c);
+
+	/* Wait for master mode selected */
+	while (!((I2C_SR1(i2c) & I2C_SR1_SB)
+		& (I2C_SR2(i2c) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
+
+	i2c_send_7bit_address(i2c, SENSOR_ADDRESS, I2C_WRITE);
+
+	/* Waiting for address is transferred. */
+	while (!(I2C_SR1(i2c) & I2C_SR1_ADDR));
+
+	/* Cleaning ADDR condition sequence. */
+	uint32_t reg32 = I2C_SR2(i2c);
+	(void) reg32; /* unused */
+
+	size_t i;
+	for (i = 0; i < n; i++) {
+		i2c_send_data(i2c, data[i]);
+		while (!(I2C_SR1(i2c) & (I2C_SR1_BTF)));
+	}
+}
+
+static void sht21_send_cmd(uint32_t i2c, uint8_t cmd)
+{
+	while ((I2C_SR2(i2c) & I2C_SR2_BUSY)) {
+	}
+
+	i2c_send_start(i2c);
+
+	/* Wait for master mode selected */
+	while (!((I2C_SR1(i2c) & I2C_SR1_SB)
+		& (I2C_SR2(i2c) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
+
+	i2c_send_7bit_address(i2c, SENSOR_ADDRESS, I2C_WRITE);
+
+	/* Waiting for address is transferred. */
+	while (!(I2C_SR1(i2c) & I2C_SR1_ADDR));
+
+	/* Cleaning ADDR condition sequence. */
+	uint32_t reg32 = I2C_SR2(i2c);
+	(void) reg32; /* unused */
+
+	i2c_send_data(i2c, cmd);
+	while (!(I2C_SR1(i2c) & (I2C_SR1_BTF)));
+}
+
+static void sht21_readn(uint32_t i2c, int n, uint8_t *res)
+{
+	//assert(n > 0);
+	i2c_send_start(i2c);
+
+	i2c_enable_ack(i2c);
+
+	/* Wait for master mode selected */
+	while (!((I2C_SR1(i2c) & I2C_SR1_SB)
+		& (I2C_SR2(i2c) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
+
+	i2c_send_7bit_address(i2c, SENSOR_ADDRESS, I2C_READ);
+
+	/* Waiting for address is transferred. */
+	while (!(I2C_SR1(i2c) & I2C_SR1_ADDR));
+	/* Cleaning ADDR condition sequence. */
+	uint32_t reg32 = I2C_SR2(i2c);
+	(void) reg32; /* unused */
+
+	int i = 0;
+	for (i = 0; i < n; ++i) {
+		if (i == n - 1) {
+			i2c_disable_ack(i2c);
+		}
+		while (!(I2C_SR1(i2c) & I2C_SR1_RxNE));
+		res[i] = i2c_get_data(i2c);
+	}
+	i2c_send_stop(i2c);
+
+	return;
+}
+
+static float sht21_convert_temp(uint16_t raw)
+{
+	//assert((raw & 0x2) == 0x2);
+	raw &= ~0x3; /* Clear lower status bits */
+	float tf = -46.85 + 175.72 * ((float) raw / 65536.0);
+	return tf;
+}
+
+static float sht21_convert_humi(uint16_t raw)
+{
+	//assert((raw & 0x2) == 0);
+	raw &= ~0x3; /* Clear lower status bits */
+	float tf = -6 + 125 * ((float) raw / 65536.0);
+	return tf;
+}
+
+static float sht21_read_temp_hold(uint32_t i2c)
+{
+	//        gpio_set(LED_DISCO_BLUE_PORT, LED_DISCO_BLUE_PIN);
+	sht21_send_cmd(i2c, SHT21_CMD_TEMP_HOLD);
+
+	uint8_t data[3];
+	sht21_readn(i2c, 2, data);
+	uint8_t crc = data[2];
+	uint16_t temp = data[0] << 8 | data[1];
+	printf("CRC=%#x, data0=%#x, data1=%#x\n", crc, data[0], data[1]);
+	//        gpio_clear(LED_DISCO_BLUE_PORT, LED_DISCO_BLUE_PIN);
+	return sht21_convert_temp(temp);
+}
+
+static float sht21_read_humi_hold(uint32_t i2c)
+{
+	//        gpio_set(LED_DISCO_BLUE_PORT, LED_DISCO_BLUE_PIN);
+	sht21_send_cmd(i2c, SHT21_CMD_HUMIDITY_HOLD);
+
+	uint8_t data[3];
+	sht21_readn(i2c, 2, data);
+	uint8_t crc = data[2];
+	uint16_t left = data[0] << 8 | data[1];
+	printf("CRC=%#x, data0=%#x, data1=%#x\n", crc, data[0], data[1]);
+
+	//        gpio_clear(LED_DISCO_BLUE_PORT, LED_DISCO_BLUE_PIN);
+	return sht21_convert_humi(left);
+}
+
+static void sht21_readid(void)
+{
+	sht21_send_cmd(I2C1, SHT21_CMD_READ_REG);
+	uint8_t raw;
+	sht21_readn(I2C1, 1, &raw);
+	printf("raw user reg = %#x\n", raw);
+	int resolution = ((raw & 0x80) >> 6) | (raw & 1);
+	printf("temp resolution is in %d bits\n", 14 - resolution);
+	printf("battery status: %s\n", (raw & (1 << 6) ? "failing" : "good"));
+	printf("On chip heater: %s\n", (raw & 0x2) ? "on" : "off");
+
+	uint8_t req1[] = {0xfa, 0x0f};
+	uint8_t res[8];
+	sht21_send_data(I2C1, 2, req1);
+	sht21_readn(I2C1, sizeof(res), res);
+	uint8_t req2[] = {0xfc, 0xc9};
+	uint8_t res2[8];
+	sht21_send_data(I2C1, 2, req2);
+	sht21_readn(I2C1, sizeof(res), res2);
+	printf("Serial = %02x%02x %02x%02x %02x%02x %02x%02x\n",
+		res2[3], res2[4], res[0], res[2], res[4], res[6], res2[0], res2[1]);
+}
+
+void i2cm_task(void)
+{
+	sht21_readid();
+	float temp = sht21_read_temp_hold(I2C1);
+	float humi = sht21_read_humi_hold(I2C1);
+	printf("Temp: %f C, RH: %f\n", temp, humi);
+
 }
\ No newline at end of file