add debounce_unit_test.cpp

examples/debounce_unit_test.cpp

@@ -0,0 +1,78 @@
+/* test debounce() function.  16/6/1 Passed test for SAMPLE_COUNT 1, 2, and 4.
+copied from keybrd/src/Row::debounce()
+
+to run test:
+    $ g++ debounce_unit_test.cpp
+    $ ./a.out
+*/
+#include <inttypes.h>
+#include <iostream>
+
+#define SAMPLE_COUNT 4      //number of consecutive equal bits needed to change a debounced bit
+
+uint8_t samples[SAMPLE_COUNT];                  //bitwise, one bit per key, most recent readings
+uint8_t samplesIndex = 0;                       //samples[] current write index
+uint8_t debounced = 0;                          //bitwise, one bit per key
+
+uint8_t debounce(const uint8_t rowState)
+{
+    uint8_t all_1 = ~0;                         //bitwise
+    uint8_t all_0 = 0;                          //bitwise
+
+    //delayMicroseconds(DELAY_MICROSECONDS);    //delay between Row scans to debounce key
+
+    samples[samplesIndex] = rowState;           //insert rowState into samples[] ring buffer
+
+    if (++samplesIndex >= SAMPLE_COUNT)         //if end of ring buffer
+    {
+        samplesIndex = 0;                       //wrap samplesIndex to beginning of ring buffer
+    }
+
+    for (uint8_t j = 0; j < SAMPLE_COUNT; j++)  //traverse the sample[] ring buffer
+    {
+        all_1 &= samples[j];                    //1 if all samples are 1
+        all_0 |= samples[j];                    //0 if all samples are 0
+    }
+
+    // update newDebounce if all the samples agree with one another
+    // if all samples=1 then newDebounced=1
+    //     elseif all samples=0 then newDebounced=0
+    //         else newDebounced=debounced i.e. no change
+    //return all_1 | (all_0 & debounced);
+    debounced = all_1 | (all_0 & debounced);
+    return debounced;
+}
+
+int main()
+{
+    //Test input and output only shows first bit of each byte.
+    const uint8_t pressed[] = {1,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,0,0,0,0};
+    const uint8_t bouncy[]  = {1,0,0,0,0,1,0,0,1,1,1,1,0,1,1,1,1,0,0,0,0};
+    const uint8_t SCAN_COUNT = sizeof(bouncy)/sizeof(*bouncy);
+    uint8_t i;
+    uint8_t newDebounced;
+
+    std::cout << "button pressed:   ";
+    for (i=0; i<SCAN_COUNT; i++)
+    {
+        std::cout << (int)pressed[i];
+    }
+    std::cout << std::endl;
+
+    std::cout << "bouncy signal:    ";
+    for (i=0; i<SCAN_COUNT; i++)
+    {
+        std::cout << (int)bouncy[i];
+    }
+    std::cout << std::endl;
+
+    std::cout << "debounced signal: ";
+    for (i=0; i<SCAN_COUNT; i++)
+    {
+        newDebounced = debounce(bouncy[i]);
+        std::cout << (int)newDebounced;
+    }
+    std::cout << std::endl;
+}
+
+void loop() { }

src/RowBase.h

@@ -6,8 +6,6 @@
 #include <RowPort.h>
 #include <ColPort.h>
 
-#define SAMPLE_COUNT 4      //number of consecutive equal bits needed to change a debounced bit
-
 /*
 Instantiation
  ------------