Support optional SoftI2C pullups on MSP430

3 files changed, 40 insertions, 20 deletions

diff --git a/src/arch/msp430fr5969lp/arch.cc b/src/arch/msp430fr5969lp/arch.cc
index 9ea49b7..ddb84a4 100644
--- a/src/arch/msp430fr5969lp/arch.cc
+++ b/src/arch/msp430fr5969lp/arch.cc
@@ -72,6 +72,13 @@ extern void loop();
 volatile char run_loop = 0;
 #endif
 
+void Arch::delay_us(unsigned char const us)
+{
+	for (int i = 0; i < us/10; i++) {
+		__delay_cycles(160);
+	}
+}
+
 void Arch::idle_loop(void)
 {
 	while (1) {
diff --git a/src/arch/msp430fr5969lp/driver/i2c.cc b/src/arch/msp430fr5969lp/driver/i2c.cc
index fffc28c..55f8591 100644
--- a/src/arch/msp430fr5969lp/driver/i2c.cc
+++ b/src/arch/msp430fr5969lp/driver/i2c.cc
@@ -16,7 +16,7 @@ signed char I2C::setup()
 	UCB0CTL1 &= ~UCSWRST;
 	UCB0I2CSA = 0;
 
-	__delay_cycles(1600);
+	arch.delay_us(100);
 
 	if (UCB0STAT & UCBBUSY)
 		return -1;
diff --git a/src/driver/soft_i2c.cc b/src/driver/soft_i2c.cc
index 94ab261..e7b8548 100644
--- a/src/driver/soft_i2c.cc
+++ b/src/driver/soft_i2c.cc
@@ -1,32 +1,45 @@
 #include "driver/soft_i2c.h"
 #include "driver/gpio.h"
+#include "arch.h"
+
+#ifdef SOFTI2C_PULLUP
+#define SDA_HIGH gpio.input(sda, 1)
+#define SDA_LOW gpio.output(sda, 0)
+#define SCL_HIGH gpio.input(scl, 1)
+#define SCL_LOW gpio.output(scl, 0)
+#else
+#define SDA_HIGH gpio.input(sda)
+#define SDA_LOW gpio.output(sda)
+#define SCL_HIGH gpio.input(scl)
+#define SCL_LOW gpio.output(scl)
+#endif
 
 signed char SoftI2C::setup()
 {
-	gpio.write(sda, 0);
-	gpio.write(scl, 0);
+	SDA_HIGH;
+	SCL_HIGH;
 	return 0;
 }
 
 void SoftI2C::start()
 {
-	gpio.input(sda);
-	gpio.input(scl);
+	SDA_HIGH;
+	SCL_HIGH;
 	//
-	gpio.output(sda);
+	SDA_LOW;
 	//
-	gpio.output(scl);
+	SCL_LOW;
 }
 
 void SoftI2C::stop()
 {
-	gpio.output(scl);
+	SCL_LOW;
 	//
-	gpio.output(sda);
+	SDA_LOW;
 	//
-	gpio.input(scl);
+	SCL_HIGH;
 	//
-	gpio.input(sda);
+	SDA_HIGH;
 }
 
 bool SoftI2C::tx(unsigned char byte)
@@ -34,20 +47,20 @@ bool SoftI2C::tx(unsigned char byte)
 	unsigned char got_ack = 0;
 	for (unsigned char i = 0; i <= 8; i++) {
 		if ((byte & 0x80) || (i == 8)) {
-			gpio.input(sda);
+			SDA_HIGH;
 		} else {
-			gpio.output(sda);
+			SDA_LOW;
 		}
 		byte <<= 1;
 		//
-		gpio.input(scl);
+		SCL_HIGH;
 		//
 		if (i == 8) {
 			if (!gpio.read(sda)) {
 				got_ack = 1;
 			}
 		}
-		gpio.output(scl);
+		SCL_LOW;
 		//
 	}
 	return got_ack;
@@ -56,21 +69,21 @@ bool SoftI2C::tx(unsigned char byte)
 unsigned char SoftI2C::rx(bool send_ack)
 {
 	unsigned char byte = 0;
-	gpio.input(sda);
+	SDA_HIGH;
 	for (unsigned char i = 0; i <= 8; i++) {
 		//
-		gpio.input(scl);
+		SCL_HIGH;
 		//
 		if ((i < 8) && gpio.read(sda)) {
 			byte |= 1 << (7 - i);
 		}
 		//
-		gpio.output(scl);
+		SCL_LOW;
 		//
 		if ((i == 7) && send_ack) {
-			gpio.output(sda);
+			SDA_LOW;
 		} else if ((i == 8) && send_ack) {
-			gpio.input(sda);
+			SDA_HIGH;
 		}
 	}
 	return byte;