From: Jan "Yenya" Kasprzak <kas@fi.muni.cz>
Date: Mon, 25 May 2015 18:20:54 +0000 (+0200)
Subject: RS485 xmit fixes
X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?p=openparking.git;a=commitdiff_plain;h=d8f201d671212ce6ea71de49e852776e5f03f4e7

RS485 xmit fixes
---

diff --git a/firmware/modbus.c b/firmware/modbus.c
index e45f5f0..b726280 100644
--- a/firmware/modbus.c
+++ b/firmware/modbus.c
@@ -28,7 +28,7 @@ typedef uint8_t  bufptr_t;
 #endif
 
 static volatile bufptr_t buf_len, tx_ptr;
-static volatile uint8_t buffer[BUFSIZE], transmitting;;
+static volatile uint8_t buffer[BUFSIZE], transmitting;
 static volatile uint16_t last_rx;
 #ifndef mb_unit_id
 static uint8_t mb_unit_id;
@@ -199,14 +199,14 @@ uint8_t modbus_poll()
 
 	switch (buffer[1]) { // function
 	case 3:
-		if (packet_len == 5)
+		if (packet_len == 6)
 			rv = read_holding_regs(
 				get_word(buffer, 2),
 				get_word(buffer, 4)
 			);
 		break;
 	case 6:
-		if (packet_len == 5)
+		if (packet_len == 6)
 			rv = write_single_reg(
 				get_word(buffer, 2),
 				get_word(buffer, 4)
@@ -267,7 +267,8 @@ ISR(USART_TX_vect)
 
 ISR(USART_UDRE_vect)
 {
-	if (tx_ptr+1 >= buf_len) {
+	if (tx_ptr >= buf_len) {
+		UCSR0A |= _BV(TXC0); // clear the pending TXC flag
 		UCSR0B |= _BV(TXCIE0); // enable xmit complete irq
 		UCSR0B &= ~_BV(UDRIE0); // disable ourselves
 	} else {
diff --git a/firmware/rs485.c b/firmware/rs485.c
index 7aec92c..7c90324 100644
--- a/firmware/rs485.c
+++ b/firmware/rs485.c
@@ -108,6 +108,7 @@ ISR(USART_UDRE_vect)
 {
 	cli();
 	if (tx_head == tx_tail) {
+		UCSR0A |= _BV(TXC0); // clear the pending TXC flag
 		UCSR0B |= _BV(TXCIE0); // enable xmit complete irq
 		UCSR0B &= ~_BV(UDRIE0);
 	} else {