Lots of changes! Takes us to rom S

[uccvend-snackrom.git] / ROM2 / sci.c

diff --git a/ROM2/sci.c b/ROM2/sci.c
index 3241f23..d7c9f28 100644 (file)
--- a/ROM2/sci.c
+++ b/ROM2/sci.c
@@ -5,6 +5,7 @@ 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 bool sci_echo;
 
 void sci_init() {
        /* assumes clock of 4.91Mhz */
@@ -14,13 +15,14 @@ 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_echo = 0;
 }
 
-void send_packet() {
+void send_buffer(bool crlf) {
        char* c;
        for (c = sci_tx_buf; *c; c++) {
                /* wait for TX ready */
@@ -29,24 +31,52 @@ 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_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 +84,10 @@ 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);
 }