From 2a621fbaf9d90ef76c38b4825023d3c3e20e47d0 Mon Sep 17 00:00:00 2001
From: hg <devnull@localhost>
Date: Thu, 5 Jun 2014 19:32:34 +0200
Subject: [PATCH] uart stuff

---
 src/main.cpp |  14 +++---
 src/uart.cpp | 126 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/uart.h   |  22 +++++++++
 3 files changed, 154 insertions(+), 8 deletions(-)
 create mode 100644 src/uart.cpp
 create mode 100644 src/uart.h

diff --git a/src/main.cpp b/src/main.cpp
index 7e346c8..4608656 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -10,15 +10,8 @@
 #include <intrinsics.h>
 #include <isr_compat.h>
 
-void delay(uint16_t c) {
-  volatile uint16_t i = c;
-  while (i--);
-}
+#include "uart.h"
 
-/*
-#pragma vector = TIMER0_A0_VECTOR
-__interrupt void TA0_ISR() {
-*/
 ISR(TIMER0_A0, TA0_ISR) {
   static uint8_t state = 0;
 
@@ -45,8 +38,13 @@ int main() {
   TACCR0 = 1000;
   TACCTL0 = CCIE;
   TACTL = MC_1 | ID_0 | TASSEL_1 | TACLR;
+
+  uartInit();
+
   __enable_interrupt();
 
+  uartWrite('W');
+
   while (1) {
     __bis_status_register(LPM0_bits);
   }
diff --git a/src/uart.cpp b/src/uart.cpp
new file mode 100644
index 0000000..ca8ac34
--- /dev/null
+++ b/src/uart.cpp
@@ -0,0 +1,126 @@
+#include <msp430g2553.h>
+#include <stdio.h>
+#include <isr_compat.h>
+
+#include "uart.h"
+
+
+
+volatile uint8_t txBuffer[UART_TX_BUFFER_SIZE+5];
+
+volatile uint8_t txBufferReadIdx = 0;
+volatile uint8_t txBufferWriteIdx = 0;
+
+volatile uint8_t rxBuffer[UART_RX_BUFFER_SIZE+5];
+volatile uint8_t rxBufferReadIdx = 0;
+volatile uint8_t rxBufferWriteIdx = 0;
+
+
+static inline void enableDataRegisterEmptyInterrupt() {
+  IE2 |= UCA0TXIE;
+}
+
+static inline void disableDataRegisterEmptyInterrupt() {
+  IE2 &= ~UCA0TXIE;
+}
+
+void uartInit() {
+  UCA0CTL1 |= UCSWRST;
+
+  UCA0CTL1 |= UCSSEL0; // ACLK
+
+  UCA0BR0 = 13;
+  UCA0BR1 = 0;
+
+  UCA0MCTL = UCBRS1 | UCBRS2;
+
+  UCA0CTL1 &= ~UCSWRST;
+
+  IE2 |= UCA0RXIE;
+
+
+//  FILE *mystdout = fdevopen(uartPutchar, NULL);
+//  stdout = mystdout;
+}
+
+void uartWrite(uint8_t o) {
+  if (txBufferWriteIdx == (UART_TX_BUFFER_SIZE - 1)) {
+    while (txBufferReadIdx == UART_TX_BUFFER_SIZE);
+  } else {
+    while (txBufferReadIdx == (txBufferWriteIdx + 1));
+  }
+
+  txBuffer[txBufferWriteIdx] = o;
+  txBufferWriteIdx++;
+
+  if (txBufferWriteIdx > UART_TX_BUFFER_SIZE) {
+    txBufferWriteIdx = 0;
+  }
+
+  enableDataRegisterEmptyInterrupt();
+}
+
+
+//int uartPutchar(char c, FILE *stream) {
+//  if (c == '\n')
+//    uartPutchar('\r', stream);
+//  uartWrite((uint8_t) c);
+//  return 0;
+//}
+
+
+ISR(USCIAB0TX, UART_TX_ISR) {
+  if ((IFG2 | UCA0TXIE) != 0) {
+    if (txBufferReadIdx != txBufferWriteIdx) {
+      UCA0TXBUF = txBuffer[txBufferReadIdx];
+      txBufferReadIdx++;
+      if (txBufferReadIdx > UART_TX_BUFFER_SIZE) {
+        txBufferReadIdx = 0;
+      }
+    } else {
+      disableDataRegisterEmptyInterrupt();
+    }
+  }
+}
+
+ISR(USCIAB0RX, UART_RX_ISR) {
+  if ((IFG2 | UCA0RXIE) != 0) {
+    if (rxBufferWriteIdx == UART_RX_BUFFER_SIZE - 1) {
+      if (rxBufferReadIdx == UART_RX_BUFFER_SIZE) {
+        // rx buffer overflow
+      }
+    } else {
+      if (rxBufferReadIdx == rxBufferWriteIdx + 1) {
+        // rx buffer overflow
+      }
+    }
+
+    rxBuffer[rxBufferWriteIdx] = UCA0RXBUF;
+    rxBufferWriteIdx++;
+
+    if (rxBufferWriteIdx > UART_RX_BUFFER_SIZE) {
+      rxBufferWriteIdx = 0;
+    }
+  }
+}
+
+uint8_t uartHasChar() {
+  return rxBufferWriteIdx != rxBufferReadIdx;
+}
+
+uint8_t uartGetChar() {
+  uint8_t c = rxBuffer[rxBufferReadIdx];
+  rxBufferReadIdx++;
+  if (rxBufferReadIdx > UART_RX_BUFFER_SIZE) {
+    rxBufferReadIdx = 0;
+  }
+  return c;
+}
+
+int uartRead() {
+  int res = -1;
+  if (uartHasChar()) {
+    res = uartGetChar();
+  }
+  return res;
+}
diff --git a/src/uart.h b/src/uart.h
new file mode 100644
index 0000000..185b9b2
--- /dev/null
+++ b/src/uart.h
@@ -0,0 +1,22 @@
+#ifndef UART_H_
+#define UART_H_
+
+#include <stdint.h>
+// #include <stdio.h>
+
+
+
+#define UART_TX_BUFFER_SIZE 32
+#define UART_RX_BUFFER_SIZE 32
+
+
+void uartInit();
+// int uartPutchar(char c, FILE *stream);
+void uartWrite(uint8_t o);
+
+uint8_t uartHasChar();
+uint8_t uartGetChar();
+
+int uartRead();
+
+#endif /* UART_H_ */