István Cserny
RTOS example - inter-task communication by using a message queue. One task provides numbers and sends them to a second task which displays them on a 4-digit 7-segment LED tube driven by two 74HC595 shift registers. Hardware: NUCLEO_F446RE board with Arduino Multifunction Shield. The ShiftOut Library by Ollie Milton …
Dependencies: mbed mbed-rtos ShiftOut
Revision 0:fb9706dc4816, committed 2022-02-24
- Comitter:
- cspista
- Date:
- Thu Feb 24 07:59:55 2022 +0000
- Commit message:
- final version
Changed in this revision
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/ShiftOut.lib Thu Feb 24 07:59:55 2022 +0000 @@ -0,0 +1,1 @@ +https://os.mbed.com/users/ollie8/code/ShiftOut/#7333dc6fca5c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Thu Feb 24 07:59:55 2022 +0000
@@ -0,0 +1,62 @@
+#include "mbed.h"
+#include "rtos.h"
+#include "ShiftOut.h" // Ollie Milton, https://os.mbed.com/users/ollie8/code/ShiftOut/
+
+DigitalOut buzzer(D3);
+Serial pc(USBTX,USBRX); //UART via ST-Link
+
+typedef uint32_t message_t;
+Queue <message_t, 4> queue;
+
+void display_thread(void const *argument)
+{
+ ShiftOut display(D7, D8, D4); // clk=D7, data=D8, latch=D4, 16)
+ uint8_t segment_data[4] = {0xFF, 0xFF, 0xFF, 0xFF}; // A frissítendő szegmenskép
+ /* Számjegyek (0 – 9) szegmensképe, negatív logikával */
+ const uint8_t SEGMENT_MAP[]= {0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90};
+ /* Számjegy (1 - 4) kiválasztó jelek */
+ const uint8_t SEGMENT_SELECT[] = {0x01, 0x02, 0x04, 0x08};
+ uint8_t i, idx = 0;
+ while (true) {
+ osEvent evt = queue.get(0); // Check for a message without waiting
+ switch(evt.status) {
+ case osEventMessage:
+ printf("osEventMessage = %#05x\n",evt.value.v); //message arrived
+ int n = evt.value.v;
+ segment_data[0] = SEGMENT_MAP[(n/1000) %10];
+ segment_data[1] = SEGMENT_MAP[(n/100) % 10];
+ segment_data[2] = SEGMENT_MAP[(n/10) % 10];
+ segment_data[3] = SEGMENT_MAP[n % 10];
+ break;
+ case osOK:
+//--- pc.printf("osOK\n"); //no error, no message arrived
+ i = idx++ & 0x03;
+ display.write(segment_data[i]);
+ display.write(SEGMENT_SELECT[i]);
+ break;
+ case osEventTimeout:
+ pc.printf("osEventTimeout\n"); //timeout occurred
+ break;
+ case osErrorParameter:
+ pc.printf("osErrorParameter\n");
+ break; //invalid parameter or is out of range.
+ default:
+ pc.printf("Unknown error flag: %#08x\n",(uint32_t)evt.status);
+ break;
+ };
+ Thread::wait(2);
+ }
+}
+
+int main (void)
+{
+ uint16_t raw;
+ Thread thread2(display_thread);
+ pc.baud(115200);
+ buzzer = true;
+ while (true) {
+ Thread::wait(1000);
+ raw++;
+ queue.put((message_t*)raw);
+ }
+}
\ No newline at end of file
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed-rtos.lib Thu Feb 24 07:59:55 2022 +0000 @@ -0,0 +1,1 @@ +https://os.mbed.com/users/mbed_official/code/mbed-rtos/#5713cbbdb706
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Thu Feb 24 07:59:55 2022 +0000 @@ -0,0 +1,1 @@ +https://os.mbed.com/users/mbed_official/code/mbed/builds/65be27845400 \ No newline at end of file