Interrupt driven I2C.

2 files changed, 156 insertions, 17 deletions

diff --git a/i2c.cpp b/i2c.cpp
index 77eb67a..03dd6b6 100644
--- a/i2c.cpp
+++ b/i2c.cpp
@@ -2,6 +2,93 @@
 
 #include "stm32.h"
 
+I2C* I2C::self;
+
+template <>
+void interrupt<Interrupt::I2C1_EV>() {
+	I2C::self->irq_ev();
+}
+
+template <>
+void interrupt<Interrupt::I2C1_ER>() {
+	I2C::self->irq_er();
+}
+
+void I2C::irq_ev() {
+	uint32_t sr1 = I2C1.SR1;
+	uint32_t sr2 = I2C1.SR2;
+	
+	// EV5, SB = 1: Start condition sent.
+	if(sr1 & 0x01) {
+		// Send address.
+		I2C1.DR = (addr << 1) | (writing ? 0 : 1);
+	}
+	
+	// EV6, ADDR = 1: Address sent.
+	if(sr1 & 0x02) {
+		if(writing) {
+			I2C1.DR = *write_p++;
+			writing--;
+		} else {
+			if(reading > 1) {
+				I2C1.CR1 |= 0x400; // Set ACK.
+			} else {
+				I2C1.CR1 |= 0x200; // Set STOP.
+			}
+		}
+	}
+	
+	// EV7, RxNE = 1: Receive buffer not empty.
+	if(sr1 & 0x40) {
+		*read_p++ = I2C1.DR;
+		reading--;
+		
+		if(reading == 1) {
+			// Unset ACK, set STOP.
+			I2C1.CR1 = (I2C1.CR1 & ~0x400) | 0x200;
+		}
+		
+		if(reading == 0) {
+			busy = 0;
+		}
+	}
+	
+	//I2C1.CR1 &= ~0x400;
+	
+	// EV8, TxE = 1, BTF = 0: Transmit buffer empty, still writing.
+	if(sr1 & 0x80 && !(sr1 & 0x04)) {
+		if(writing) {
+			// Send data.
+			I2C1.DR = *write_p++;
+			writing--;
+		} else {
+			// All data sent.
+			
+			if(reading) {
+				// Send repeat start.
+				I2C1.CR1 |= 0x100;
+			} else {
+				// Send stop.
+				I2C1.CR1 |= 0x200;
+				busy = 0;
+			}
+		}
+	}
+}
+
+void I2C::irq_er() {
+	handle_error();
+}
+
+void I2C::handle_error() {
+	I2C1.SR1;
+	I2C1.SR2;
+	
+	//while(1);
+	I2C1.CR1 |= 0x200;
+	busy = 0;
+}
+
 void I2C::enable() {
 	RCC.enable(RCC.I2C1);
 	asm volatile("nop");
@@ -9,52 +96,79 @@ void I2C::enable() {
 	I2C1.CR1 = 0x8000;
 	I2C1.CR1 = 0;
 	
-	I2C1.CR2 = 36;
+	I2C1.CR2 = 0x700 | 36;
 	I2C1.TRISE = 37;
 	I2C1.CCR = 180;
+	
+	Interrupt::enable(Interrupt::I2C1_EV);
+	Interrupt::enable(Interrupt::I2C1_ER);
+	
 	I2C1.CR1 = 1;
 }
 
-void I2C::write_reg(uint8_t addr, uint8_t reg, uint8_t data) {
+void I2C::write_reg(uint8_t addr_, uint8_t reg, uint8_t data) {
+	addr = addr_;
+	writing = 2;
+	reading = 0;
+	volatile uint8_t buf[] = {reg, data};
+	write_p = buf;
+	busy = 1;
+	
 	I2C1.CR1 |= 0x100;
-	while(!(I2C1.SR1 & 0x01));
+	
+	while(busy);
+	
+	/*
+	while(!(I2C1.SR1 & 0x01)); // Wait for SB.
 	
 	I2C1.DR = (addr << 1) | 0;
-	while (!(I2C1.SR1 & 0x02));
+	while (!(I2C1.SR1 & 0x02)); // Wait for ADDR.
 	I2C1.SR2;
 	
 	I2C1.DR = reg;
-	while (!(I2C1.SR1 & 0x80));
+	while (!(I2C1.SR1 & 0x80)); // Wait for TxE.
 	
 	I2C1.DR = data;
-	while (!(I2C1.SR1 & 0x04));
+	while (!(I2C1.SR1 & 0x04)); // Wait for BTF.
 	
-	I2C1.CR1 |= 0x200;
+	I2C1.CR1 |= 0x200;*/
 }
 
-void I2C::read_reg(uint8_t addr, uint8_t reg, uint8_t len, uint8_t* buf) {
+void I2C::read_reg(uint8_t addr_, uint8_t reg, uint8_t len, uint8_t* buf) {
+	addr = addr_;
+	writing = 1;
+	reading = len;
+	write_p = &reg;
+	read_p = buf;
+	busy = 1;
+	
+	I2C1.CR1 |= 0x100;
+	
+	while(busy);
+	
+	/*
 	I2C1.CR1 |= 0x100;
-	while(!(I2C1.SR1 & 0x01));
+	while(!(I2C1.SR1 & 0x01)); // Wait for SB.
 	
 	I2C1.DR = (addr << 1) | 0;
-	while (!(I2C1.SR1 & 0x02));
+	while (!(I2C1.SR1 & 0x02)); // Wait for ADDR.
 	I2C1.SR2;
 	
 	I2C1.DR = reg;
-	while (!(I2C1.SR1 & 0x80));
+	while (!(I2C1.SR1 & 0x80)); // Wait for TxE.
 	
 	I2C1.CR1 |= 0x100;
-	while(!(I2C1.SR1 & 0x01));
+	while(!(I2C1.SR1 & 0x01)); // Wait for SB.
 	
 	I2C1.DR = (addr << 1) | 1;
-	while (!(I2C1.SR1 & 0x02));
+	while (!(I2C1.SR1 & 0x02)); // Wait for ADDR.
 	I2C1.SR2;
 	
 	I2C1.CR1 |= 0x400; // Set ACK.
 	
 	while(len) {
 		if(len == 3) {
-			while (!(I2C1.SR1 & 0x04)); // Wait for BTF
+			while (!(I2C1.SR1 & 0x04)); // Wait for BTF.
 			
 			I2C1.CR1 &= ~0x400; // Clear ACK.
 			*buf++ = I2C1.DR;
@@ -65,10 +179,11 @@ void I2C::read_reg(uint8_t addr, uint8_t reg, uint8_t len, uint8_t* buf) {
 			len--;
 			
 		} else {
-			while (!(I2C1.SR1 & 0x40)); // Wait for RXNE
+			while (!(I2C1.SR1 & 0x40)); // Wait for RxNE.
 			
 			*buf++ = I2C1.DR;
 			len--;
 		}
 	}
+	*/
 }
diff --git a/i2c.h b/i2c.h
index 0681160..3d58056 100644
--- a/i2c.h
+++ b/i2c.h
@@ -3,12 +3,36 @@
 
 #include <stdint.h>
 
+#include "interrupt.h"
+
 class I2C {
+	friend void interrupt<Interrupt::I2C1_EV>();
+	friend void interrupt<Interrupt::I2C1_ER>();
+	
+	private:
+		static I2C* self;
+		
+		volatile uint8_t addr;
+		volatile uint8_t writing;
+		volatile uint8_t reading;
+		volatile uint8_t* write_p;
+		volatile uint8_t* read_p;
+		
+		volatile bool busy;
+		
+		void irq_ev();
+		void irq_er();
+		void handle_error();
+	
 	public:
+		I2C() {
+			self = this;
+		}
+		
 		void enable();
 		
-		void write_reg(uint8_t addr, uint8_t reg, uint8_t data);
-		void read_reg(uint8_t addr, uint8_t reg, uint8_t len, uint8_t* buf);
+		void write_reg(uint8_t addr_, uint8_t reg, uint8_t data);
+		void read_reg(uint8_t addr_, uint8_t reg, uint8_t len, uint8_t* buf);
 };