X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=ROM2%2Fsci.c;h=3241f23c2cd971b34b6a31f7705ebfe8b5ab1426;hb=8e227175f6eeb47fc66679478840dce339941f44;hp=39006bc0abc21277edfedba7e5a6be3e1660bfb6;hpb=b3523cf99eff476642609ad6537e460595f84e72;p=uccvend-snackrom.git

diff --git a/ROM2/sci.c b/ROM2/sci.c
index 39006bc..3241f23 100644
--- a/ROM2/sci.c
+++ b/ROM2/sci.c
@@ -1,11 +1,73 @@
 #include "vend.h"
 #include "sci.h"
 
+char sci_tx_buf[BUFFER_LEN];
+volatile char sci_rx_buf[BUFFER_LEN];
+volatile bool sci_have_packet;
+volatile u8 sci_rx_buf_ptr;
+
 void sci_init() {
-	_io_ports[M6811_BAUD] = M6811_DEF_BAUD;
+	/* assumes clock of 4.91Mhz */
+	_io_ports[M6811_BAUD] = 0x03; /* 9600 baud */
+
 	/* Setup character format 1 start, 8-bits, 1 stop.  */
 	_io_ports[M6811_SCCR1] = 0;
 
-	/* Enable reciever and transmitter.  */
-	_io_ports[M6811_SCCR2] = 0xc;
+	/* Enable reciever and transmitter & rx interrupt.  */
+	_io_ports[M6811_SCCR2] = 0x2c;
+
+	sci_have_packet = 0;
+	sci_rx_buf_ptr = 0;
+}
+
+void send_packet() {
+	char* c;
+	for (c = sci_tx_buf; *c; c++) {
+		/* wait for TX ready */
+		while (!(_io_ports[M6811_SCSR] & M6811_TDRE));
+
+		/* send byte */
+		_io_ports[M6811_SCDR] = *c;
+	}
+}
+
+void rx_int() {
+	if (sci_have_packet) return;
+	if (sci_rx_buf_ptr >= BUFFER_LEN) {
+		/* overrun :( */
+		sci_rx_buf[BUFFER_LEN] = '\0';
+		sci_have_packet = 1;
+		sci_rx_buf_ptr = 0;
+		return;
+	}
+	sci_rx_buf[sci_rx_buf_ptr] = _io_ports[M6811_SCDR];
+	if (sci_rx_buf[sci_rx_buf_ptr] == '\n') {
+		sci_rx_buf[sci_rx_buf_ptr] = '\0';
+		sci_have_packet = 1;
+		sci_rx_buf_ptr = 0;
+	}
+	sci_rx_buf_ptr++;
+}
+
+void msg_clr() {
+	sci_have_packet = 0;
+	sci_rx_buf_ptr = 0;
+}
+
+void sci_interrupt_serial() {
+	if (_io_ports[M6811_SCSR] & M6811_RDRF) rx_int();
+}
+
+void send_ack() {
+	sci_tx_buf[0] = '!';
+	sci_tx_buf[1] = '\n';
+	sci_tx_buf[2] = '\0';
+	send_packet();
+}
+
+void send_nack() {
+	sci_tx_buf[0] = '?';
+	sci_tx_buf[1] = '\n';
+	sci_tx_buf[2] = '\0';
+	send_packet();
 }