X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=ROM2%2Fsci.c;h=fe59f75b1b6c478a9cfaa5d5e7ebbbec1ce77e4a;hb=31352d878e591a3e7deb159fd9b65a2fb6706fa9;hp=3241f23c2cd971b34b6a31f7705ebfe8b5ab1426;hpb=c34cbe163ce52f1d8fc553993701054f4942152f;p=uccvend-snackrom.git

diff --git a/ROM2/sci.c b/ROM2/sci.c
index 3241f23..fe59f75 100644
--- a/ROM2/sci.c
+++ b/ROM2/sci.c
@@ -5,6 +5,9 @@ char sci_tx_buf[BUFFER_LEN];
 volatile char sci_rx_buf[BUFFER_LEN];
 volatile bool sci_have_packet;
 volatile u8 sci_rx_buf_ptr;
+volatile u8 sci_rx_buf_ptr_start;
+volatile bool sci_echo;
+bool sci_doing_xmodem;
 
 void sci_init() {
 	/* assumes clock of 4.91Mhz */
@@ -14,13 +17,16 @@ void sci_init() {
 	_io_ports[M6811_SCCR1] = 0;
 
 	/* Enable reciever and transmitter & rx interrupt.  */
-	_io_ports[M6811_SCCR2] = 0x2c;
+	_io_ports[M6811_SCCR2] = M6811_RIE | M6811_TE | M6811_RE;
 
 	sci_have_packet = 0;
 	sci_rx_buf_ptr = 0;
+	sci_rx_buf_ptr_start = 0;
+	sci_echo = 0;
+	sci_doing_xmodem = 0;
 }
 
-void send_packet() {
+void send_buffer(bool crlf) {
 	char* c;
 	for (c = sci_tx_buf; *c; c++) {
 		/* wait for TX ready */
@@ -29,24 +35,62 @@ void send_packet() {
 		/* send byte */
 		_io_ports[M6811_SCDR] = *c;
 	}
+	if (!crlf) return;
+	/* send CRLF */
+	while (!(_io_ports[M6811_SCSR] & M6811_TDRE));
+	_io_ports[M6811_SCDR] = '\r';
+	while (!(_io_ports[M6811_SCSR] & M6811_TDRE));
+	_io_ports[M6811_SCDR] = '\n';
 }
 
-void rx_int() {
-	if (sci_have_packet) return;
-	if (sci_rx_buf_ptr >= BUFFER_LEN) {
+void send_string(char* c) {
+	for (; *c; c++) {
+		while (!(_io_ports[M6811_SCSR] & M6811_TDRE)); /* wait for TX ready */
+		_io_ports[M6811_SCDR] = *c; /* send byte */
+	}
+}
+
+void sci_rx_int() {
+	char buf = _io_ports[M6811_SCDR];
+	if (sci_doing_xmodem) {
+		if ((sci_rx_buf_ptr+1)%BUFFER_LEN == sci_rx_buf_ptr_start) {
+			/* we drop following bytes :( */
+			return;
+		}
+		sci_rx_buf[sci_rx_buf_ptr] = buf;
+		sci_rx_buf_ptr++;
+		sci_rx_buf_ptr %= BUFFER_LEN;
+		return;
+	}
+	if (sci_echo) {
+		while (!(_io_ports[M6811_SCSR] & M6811_TDRE)); /* wait for TX ready */
+		_io_ports[M6811_SCDR] = buf; /* send byte */
+	}
+
+	/* XXX FIXME we should do something about errors. nack? */
+	if (sci_have_packet) {
 		/* 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] = buf;
+
+	if (buf == '\n' || buf == '\r') {
 		sci_rx_buf[sci_rx_buf_ptr] = '\0';
 		sci_have_packet = 1;
-		sci_rx_buf_ptr = 0;
 	}
-	sci_rx_buf_ptr++;
+
+	if (sci_rx_buf_ptr+1 < BUFFER_LEN)
+		sci_rx_buf_ptr++;
+	else {
+		sci_rx_buf[BUFFER_LEN-1] = '\0'; /* this is as much as we could fit */
+	}
+}
+
+void sci_interrupt_serial() {
+	if (_io_ports[M6811_SCSR] & M6811_RDRF) sci_rx_int();
+
+	if (_io_ports[M6811_SCSR] & M6811_OR)
+		_io_ports[M6811_SCDR]; /* declare it a lost cause */
 }
 
 void msg_clr() {
@@ -54,20 +98,32 @@ void msg_clr() {
 	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();
+	send_string("!" CRLF);
 }
 
 void send_nack() {
-	sci_tx_buf[0] = '?';
-	sci_tx_buf[1] = '\n';
-	sci_tx_buf[2] = '\0';
-	send_packet();
+	send_string("?" CRLF);
+}
+
+u16 sci_timer;
+void serial_rti() { /* called every 6.6 ms */
+	if (sci_timer) sci_timer--;
+}
+
+/* for gdb compatibility */
+int serial_readchar(u8 timeout) {
+	sci_timer = timeout * 152;
+	while (sci_timer && sci_rx_buf_ptr_start == sci_rx_buf_ptr); /* spin */
+	if (sci_timer == 0) return SERIAL_TIMEOUT;
+	return sci_rx_buf[sci_rx_buf_ptr_start++];
+}
+
+void serial_write(const char *str, int len) {
+	char *c, *end;
+	end = (char*)(str + len);
+	for (c = (char*)str; c < end; c++) {
+		while (!(_io_ports[M6811_SCSR] & M6811_TDRE)); /* wait for TX ready */
+		_io_ports[M6811_SCDR] = *c; /* send byte */
+	}
 }