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Switched tc5 aprs to 16-bit mode to reduce error. Reduced pre-scaler

master
Richard Meadows 2015-06-25 18:16:24 +01:00
rodzic 158e8e618a
commit 5186d5f3df
2 zmienionych plików z 8 dodań i 8 usunięć
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2
firmware/Peripherals.md
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@ -13,7 +13,7 @@
||tc2|counts cycles of tcxo. 32-bit
||tc3|^^^^^
||tc4|osc8m event source
||tc5|telemetry pwm 16-bit, ALSO aprs carrier 8-bit
||tc5|telemetry pwm 16-bit, ALSO aprs carrier 16-bit
|
|*EXTINT*|
||extint[5]|gps timepulse

14
firmware/src/ax25.c
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@ -154,12 +154,12 @@ void ax25_gpio1_pwm_init(void)
{
float gclk1_frequency = (float)system_gclk_gen_get_hz(1);
float divide_needed = round(gclk1_frequency / (13200*4));
float divide_needed = round(gclk1_frequency / 13200);
uint32_t top = (uint32_t)divide_needed & ~0x1;
uint32_t capture = top >> 1; /* 50% duty cycle */
if (top > 0xFF) while (1); // It's only an 8-bit counter
if (top > 0xFFFF) while (1); // It's only an 16-bit counter
/* Setup GCLK genertor 7 */
system_gclk_gen_set_config(GCLK_GENERATOR_7,
@ -171,14 +171,14 @@ void ax25_gpio1_pwm_init(void)
system_gclk_gen_enable(GCLK_GENERATOR_7);
/* Configure timer */
bool capture_channel_enables[] = {false, true};
uint32_t compare_channel_values[] = {0x0000, capture};
bool capture_channel_enables[] = {false, false};
uint32_t compare_channel_values[] = {top, capture};
tc_init(TC5,
GCLK_GENERATOR_7,
TC_COUNTER_SIZE_8BIT,
TC_CLOCK_PRESCALER_DIV4,
TC_WAVE_GENERATION_NORMAL_PWM,
TC_COUNTER_SIZE_16BIT,
TC_CLOCK_PRESCALER_DIV1,
TC_WAVE_GENERATION_MATCH_PWM,
TC_RELOAD_ACTION_GCLK,
TC_COUNT_DIRECTION_UP,
TC_WAVEFORM_INVERT_OUTPUT_NONE,