1 files changed, 74 insertions, 0 deletions
diff --git a/i2c.cpp b/i2c.cpp
new file mode 100644
index 0000000..90c0ce1
--- /dev/null
+++ b/i2c.cpp
@@ -0,0 +1,74 @@
+#include "i2c.h"
+
+#include "stm32.h"
+
+void I2C::enable() {
+	RCC.enable(RCC.I2C2);
+	asm volatile("nop");
+	
+	I2C2.CR1 = 0x8000;
+	I2C2.CR1 = 0;
+	
+	I2C2.CR2 = 36;
+	I2C2.TRISE = 37;
+	I2C2.CCR = 180;
+	I2C2.CR1 = 1;
+}
+
+void I2C::write_reg(uint8_t addr, uint8_t reg, uint8_t data) {
+	I2C2.CR1 |= 0x100;
+	while(!(I2C2.SR1 & 0x01));
+	
+	I2C2.DR = (addr << 1) | 0;
+	while (!(I2C2.SR1 & 0x02));
+	I2C2.SR2;
+	
+	I2C2.DR = reg;
+	while (!(I2C2.SR1 & 0x80));
+	
+	I2C2.DR = data;
+	while (!(I2C2.SR1 & 0x04));
+	
+	I2C2.CR1 |= 0x200;
+}
+
+void I2C::read_reg(uint8_t addr, uint8_t reg, uint8_t len, uint8_t* buf) {
+	I2C2.CR1 |= 0x100;
+	while(!(I2C2.SR1 & 0x01));
+	
+	I2C2.DR = (addr << 1) | 0;
+	while (!(I2C2.SR1 & 0x02));
+	I2C2.SR2;
+	
+	I2C2.DR = reg;
+	while (!(I2C2.SR1 & 0x80));
+	
+	I2C2.CR1 |= 0x100;
+	while(!(I2C2.SR1 & 0x01));
+	
+	I2C2.DR = (addr << 1) | 1;
+	while (!(I2C2.SR1 & 0x02));
+	I2C2.SR2;
+	
+	I2C2.CR1 |= 0x400; // Set ACK.
+	
+	while(len) {
+		if(len == 3) {
+			while (!(I2C2.SR1 & 0x04)); // Wait for BTF
+			
+			I2C2.CR1 &= ~0x400; // Clear ACK.
+			*buf++ = I2C2.DR;
+			len--;
+			
+			I2C2.CR1 |= 0x200; // Set STOP.
+			*buf++ = I2C2.DR;
+			len--;
+			
+		} else {
+			while (!(I2C2.SR1 & 0x40)); // Wait for RXNE
+			
+			*buf++ = I2C2.DR;
+			len--;
+		}
+	}
+}