István Cserny
RTOS example - multiplex display 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 was applied.
Dependencies: mbed mbed-rtos ShiftOut
Diff: main.cpp
- Revision:
- 0:2ae7b6b39e93
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Thu Feb 24 07:52:29 2022 +0000
@@ -0,0 +1,40 @@
+#include "mbed.h"
+#include "rtos.h"
+#include "ShiftOut.h" // Ollie Milton, https://os.mbed.com/users/ollie8/code/ShiftOut/
+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};
+
+Thread thread;
+DigitalOut buzzer(D3);
+
+void led2_thread()
+{
+ ShiftOut display(D7, D8, D4); // clk=D7, data=D8, latch=D4)
+ while (true) {
+ for(int i = 0; i<4; i++) {
+ display.write(segment_data[i]);
+ display.write(SEGMENT_SELECT[i]);
+ Thread::wait(2);
+ }
+ }
+}
+
+int main()
+{
+ int n =0;
+ buzzer = true;
+ thread.start(led2_thread);
+
+ while (true) {
+ 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];
+ n = n+1;
+ buzzer = (n%100) != 0;
+ Thread::wait(250);
+ }
+}
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