wayne roberts
demonstration of using serial port as console/terminal
Demonstration of using serial port with a dumb terminal. Such as teraterm. This example uses serial port at 57600bps.
purpose
provide quick/easy user interface.
features
- backspace key stops at start of line
- <enter> on empty line repeats last command
- Ctrl-C can be used to abort something
teraterm console
reset > ? . print status led toggle LED da<%d> get/set my_data > . LED1:0 my_data:0 > led > . LED1:1 my_data:0 > da data:0 > da1337 data:1337 > . LED1:1 my_data:1337 > led > > > >
Diff: main.cpp
- Revision:
- 0:9a142eb22e83
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Thu Nov 06 02:58:50 2014 +0000
@@ -0,0 +1,110 @@
+#include "mbed.h"
+
+Serial pc(USBTX, USBRX);
+char pcbuf[64];
+
+DigitalOut myled(LED1);
+
+uint16_t my_data;
+
+void service_something()
+{
+ /* poll something while waiting for keyboard */
+}
+
+int get_kbd_str(char* buf, int size)
+{
+ char c;
+ int i;
+ static int prev_len;
+
+ for (i = 0;;) {
+ if (pc.readable()) {
+ c = pc.getc();
+ if (c == 8) { // backspace
+ if (i > 0) {
+ pc.putc(8);
+ pc.putc(' ');
+ pc.putc(8);
+ i--;
+ }
+ } else if (c == '\r') {
+ if (i == 0) {
+ return prev_len; // repeat previous
+ } else {
+ buf[i] = 0; // null terminate
+ prev_len = i;
+ return i;
+ }
+ } else if (c == 3) {
+ // ctrl-C abort
+ return -1;
+ } else if (i < size) {
+ buf[i++] = c;
+ pc.putc(c);
+ }
+ } else {
+ service_something();
+ }
+ } // ...for()
+}
+
+void
+print_status()
+{
+ printf("LED1:%d\r\n", myled.read());
+ printf("my_data:%d\n", my_data);
+}
+
+void console()
+{
+ int len, n;
+
+ len = get_kbd_str(pcbuf, sizeof(pcbuf));
+ if (len < 0) {
+ printf("abort\r\n");
+ return;
+ }
+
+ printf("\r\n");
+ if (len == 1) {
+ /* single character handling */
+ switch (pcbuf[0]) {
+ case '?':
+ printf(". print status\r\n");
+ printf("led toggle LED\r\n");
+ printf("da<%%d> get/set my_data\r\n");
+ break;
+ case '.':
+ print_status();
+ break;
+ } // ...switch (pcbuf[0])
+ } else if (pcbuf[0] == 'l' && pcbuf[1] == 'e' && pcbuf[2] == 'd') {
+ if (myled.read()) // invert LED state
+ myled = 0;
+ else
+ myled = 1;
+ } else if (pcbuf[0] == 'd' && pcbuf[1] == 'a') {
+ if (pcbuf[2] >= '0' && pcbuf[2] <= '9') {
+ sscanf(pcbuf+2, "%d", &n);
+ my_data = n; // set user data
+ }
+ printf("data:%d\r\n", my_data); // show current value;
+ }
+
+ printf("> ");
+ fflush(stdout);
+}
+
+int main()
+{
+ pc.baud(57600);
+ printf("\r\nreset\r\n");
+
+ printf("> ");
+ fflush(stdout);
+
+ while (1) {
+ console();
+ }
+}
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