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| author | Waleed El-Geresy <waleed.el-geresy15@imperial.ac.uk> | 2017-05-08 12:06:25 +0100 |
|---|---|---|
| committer | Vasil Zlatanov <v@skozl.com> | 2017-05-10 16:39:44 +0100 |
| commit | ae77622c84de56d1183a98b85b60ac9411b4bebf (patch) | |
| tree | 1636c9bdd24c91c2eebeea46ea5ec20ed4064733 | |
| parent | ada3557c0a579f89f20ee3d1da7e1cceb24685db (diff) | |
| download | e2-switch-ae77622c84de56d1183a98b85b60ac9411b4bebf.tar.gz e2-switch-ae77622c84de56d1183a98b85b60ac9411b4bebf.tar.bz2 e2-switch-ae77622c84de56d1183a98b85b60ac9411b4bebf.zip | |
Add lookup table
| -rw-r--r-- | src/main.cpp | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/src/main.cpp b/src/main.cpp index 1406b74..9cc47fb 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -6,6 +6,7 @@ #define SW_PINS p24, p23, p22, p21 #define SW_PERIOD 20000 // 20ms +#define ARRAY_SIZE 360 void tout(void); void square(void); @@ -30,16 +31,24 @@ volatile uint16_t update = 0; volatile uint16_t amp = 0; const double pi = 3.141592653589793238462; -const double offset = 65535/2; +const double offset = 65535/2; //Offset is 1/2 the total bits double rads = 0.0; uint16_t sample = 0; +uint16_t sineArray[ARRAY_SIZE]; + // Initialise display SPInit gSpi(D_MOSI_PIN, NC, D_CLK_PIN); Adafruit_SSD1306_Spi oled(gSpi, D_DC_PIN, D_RST_PIN, D_CS_PIN, 64, 128); int main(void) { + for(int i=0; i<ARRAY_SIZE; i++) + { + int rads = (pi * i) / (ARRAY_SIZE/2.0f); + sineArray[i] = (uint16_t)(0.5f * (offset * (cos(rads + pi))) + offset); + } + uint16_t frequency = 0; uint16_t old_frequency = 0; @@ -123,11 +132,11 @@ void triangle(void){ } void sine(void){ - rads = (pi * amp) / 180.0f; - sample = (uint16_t)(0.5f * (offset * (cos(rads + pi))) + offset); - out_wave.write_u16(sample); + if(amp == ARRAY_SIZE) + amp = 0; + + out_wave.write_u16(sineArray[amp]); amp++; - if(amp == 360) - amp = 0; } + |