1 files changed, 93 insertions, 0 deletions
diff --git a/main/i2c.c b/main/i2c.c
new file mode 100644
index 0000000..b324124
--- /dev/null
+++ b/main/i2c.c
@@ -0,0 +1,93 @@
+#include "i2c.h"
+#include "init.h"
+
+#include <stdio.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <pico/stdlib.h>
+#include <hardware/i2c.h>
+
+void init_i2c() {
+	i2c_init(I2C_PORT, 100 * 1000); // currently at 100kHz
+
+	// Initialize I2C pins - sda(16), scl(17)
+	gpio_set_function(SDA_PIN, GPIO_FUNC_I2C);
+	gpio_set_function(SCL_PIN, GPIO_FUNC_I2C);
+
+	gpio_pull_up(SDA_PIN);
+	gpio_pull_up(SCL_PIN);
+}
+
+int read_i2c(uint8_t addr, uint8_t *output, size_t len) {
+	// false - finished with bus
+	return i2c_read_blocking (I2C_PORT, addr, output, len, false);
+}
+
+int write_i2c(uint8_t addr, uint8_t *input, size_t len) {
+	// true to keep master control of bus
+	return i2c_write_blocking (I2C_PORT, addr, input, len, true);
+}
+
+bool reserved_addr(uint8_t addr) {
+	return (addr & 0x78) == 0 || (addr & 0x78) == 0x78;
+}
+
+void init_addr_array(uint8_t array[], int size) {
+	for(int i = 0; i < size; i++){
+		array[i] = 0x00;
+	}
+}
+
+uint8_t* scan_bus(uint8_t *array) {
+	int ret;
+	int i = 0;
+	uint8_t rxdata;
+
+	for(int addr = 0; addr < (1<<7); addr++) {
+		// ignore reserved addresses
+		// These are any addresses of the form 000 0xxx or 111 1xxx
+		if( reserved_addr(addr) ){
+			ret = PICO_ERROR_GENERIC;
+		}else{
+			ret = i2c_read_blocking(I2C_PORT, addr, &rxdata, 1, false);
+		}
+
+		// if acknowledged -> ret == number of bytes sent
+		if(ret > 0){
+			printf("found i2c slave on addr: %d\n", addr);
+			array[i] = addr;
+			i++;
+		}
+	}
+
+	return array;
+}
+
+void bus_task() {
+	// scan bus for slaves
+	// send updates at regular intervals
+	await_init();
+	
+	int i = 0;
+	uint8_t found[MAX_SLAVES];
+	init_addr_array(found, MAX_SLAVES);
+
+	while(1) {
+		// printf("Bus scan!");
+		scan_bus(found);
+
+		for(int i = 0; i < MAX_SLAVES; i++){
+			if( found[i] == 0x00 )
+				break;
+			
+			uint8_t data = 0x01;
+			// send data to found slave address
+			write_i2c(found[i], &data, 1);
+
+			data = 0x02;
+			write_i2c(found[i], &data, 1);
+			// request update from slave addr at found[i]
+			//write_i2c();
+		}
+	}
+}