From 658ca283452c5944c55d9c751868eef6c6f34138 Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Tue, 17 Jul 2018 09:48:54 +0200
Subject: MSP430: Some idle waiting

---
 src/arch/msp430fr5969lp/arch.cc       |  2 ++
 src/arch/msp430fr5969lp/driver/i2c.cc | 29 +++++++++++++++++++++++------
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/src/arch/msp430fr5969lp/arch.cc b/src/arch/msp430fr5969lp/arch.cc
index 3016842..9ea49b7 100644
--- a/src/arch/msp430fr5969lp/arch.cc
+++ b/src/arch/msp430fr5969lp/arch.cc
@@ -79,6 +79,7 @@ void Arch::idle_loop(void)
 		asm volatile("nop");
 		__bis_SR_register(LPM2_bits);
 		asm volatile("nop");
+		__dint();
 #if defined(WITH_LOOP)
 		if (run_loop) {
 			loop();
@@ -97,6 +98,7 @@ void Arch::idle(void)
 	asm volatile("nop");
 	__bis_SR_register(LPM2_bits);
 	asm volatile("nop");
+	__dint();
 #ifdef WITH_WAKEUP
 		wakeup();
 #endif
diff --git a/src/arch/msp430fr5969lp/driver/i2c.cc b/src/arch/msp430fr5969lp/driver/i2c.cc
index 5f1f4c1..fffc28c 100644
--- a/src/arch/msp430fr5969lp/driver/i2c.cc
+++ b/src/arch/msp430fr5969lp/driver/i2c.cc
@@ -1,6 +1,9 @@
 #include "driver/i2c.h"
+#include "arch.h"
 #include <msp430.h>
 
+volatile unsigned short old_ifg = 0;
+
 signed char I2C::setup()
 {
 	UCB0CTL1 = UCSWRST;
@@ -47,17 +50,25 @@ signed char I2C::xmit(unsigned char address,
 	if (tx_len) {
 		UCB0CTL1 |= UCTR | UCTXSTT;
 		for (i = 0; i < tx_len; i++) {
-			while (!(UCB0IFG & (UCTXIFG0 | UCNACKIFG | UCCLTOIFG)));
-			if (UCB0IFG & (UCNACKIFG | UCCLTOIFG)) {
-				UCB0IFG &= ~UCNACKIFG;
-				UCB0IFG &= ~UCCLTOIFG;
+			UCB0IFG = 0;
+			old_ifg = 0;
+			UCB0IE = UCTXIE0 | UCNACKIE | UCCLTOIE;
+			while (!(old_ifg & (UCTXIFG0 | UCNACKIFG | UCCLTOIFG))) {
+				arch.idle();
+			}
+			UCB0IE = 0;
+			if (old_ifg & (UCNACKIFG | UCCLTOIFG)) {
 				UCB0CTL1 |= UCTXSTP;
 				return -1;
 			}
+			old_ifg = 0;
 			UCB0TXBUF = tx_buf[i];
 		}
-		while (!(UCB0IFG & (UCTXIFG0 | UCNACKIFG | UCCLTOIFG)));
-		UCB0IFG &= ~(UCTXIFG0 | UCNACKIFG);
+		UCB0IE = UCTXIE0 | UCNACKIE | UCCLTOIE;
+		while (!(old_ifg & (UCTXIFG0 | UCNACKIFG | UCCLTOIFG))) {
+			arch.idle();
+		}
+		UCB0IE = 0;
 		//if (UCB0IFG & (UCNACKIFG | UCCLTOIFG)) {
 		//	UCB0IFG &= ~UCNACKIFG;
 		//	UCB0IFG &= ~UCCLTOIFG;
@@ -90,4 +101,10 @@ signed char I2C::xmit(unsigned char address,
 	return 0;
 }
 
+__attribute__((interrupt(USCI_B0_VECTOR))) __attribute__((wakeup)) void handle_usci_b0()
+{
+	old_ifg = UCB0IFG;
+	UCB0IFG = 0;
+}
+
 I2C i2c;
-- 
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