Mercurial > ~darius > hgwebdir.cgi > modulator
diff modulator.c @ 27:e1d8fe3e418a
Run PIOs at 1x with delays and sync.
Can now use a single trigger to set both DAC & ctrl.
DAC [still] jitters against the ctrl though..
| author | Daniel O'Connor <darius@dons.net.au> |
|---|---|
| date | Wed, 26 Feb 2025 11:03:59 +1030 |
| parents | 336f06fa6e47 |
| children | 600a394629e6 |
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--- a/modulator.c Tue Feb 25 17:03:51 2025 +1030 +++ b/modulator.c Wed Feb 26 11:03:59 2025 +1030 @@ -362,9 +362,9 @@ } dac_sm = pio_claim_unused_sm(pulse_pio, true); // Data is GPIO7 to GPIO14, clock is GPIO15 - // Clock divisor of 2 so it runs at 60MHz and - // generates a 30MHz clock - dac_program_init(pulse_pio, dac_sm, dac_pio_sm_offset, DACOUT_GPIO, 2); + // Clock divisor of 1 but the PIO has delays so it runs at 60MHz + // and generates a 30MHz clock + dac_program_init(pulse_pio, dac_sm, dac_pio_sm_offset, DACOUT_GPIO, 1); // Configure a channel to write 32 bits at a time to PIO0 // SM0's TX FIFO, paced by the data request signal from that peripheral. @@ -398,7 +398,7 @@ __breakpoint(); } ctrl_sm = pio_claim_unused_sm(pulse_pio, true); - ctrl_program_init(pulse_pio, ctrl_sm, ctrl_pio_sm_offset, CTRLOUT_GPIO, 2); + ctrl_program_init(pulse_pio, ctrl_sm, ctrl_pio_sm_offset, CTRLOUT_GPIO, 1); // Configure a channel to write 32 bits at a time to PIO0 // SM0's TX FIFO, paced by the data request signal from that peripheral. @@ -427,9 +427,19 @@ __breakpoint(); } uint trigger_sm = pio_claim_unused_sm(pulse_pio, true); - trigger_program_init(pulse_pio, trigger_sm, trigger_pio_sm_offset, TRIGIN_GPIO, 2); + trigger_program_init(pulse_pio, trigger_sm, trigger_pio_sm_offset, TRIGIN_GPIO, 1); #endif + // Start & sync all state machines + // This is necessary to avoid any jitter and to make the + // trigger sync work correctly + pio_enable_sm_mask_in_sync(pulse_pio, + 1u << dac_sm | + 1u << ctrl_sm | +#ifdef WITH_TRIGGER + 1u << trigger_sm +#endif + ); // // Setup PWM // Used here to output a trigger which gets fed back into the trigger SM @@ -439,8 +449,8 @@ // could further subdivide in the IRQ handler pwm_config c = pwm_get_default_config(); pwm_config_set_clkdiv_int(&c, 250); - // 8Hz - pwm_config_set_wrap(&c, 60000 - 1); + // 80Hz + pwm_config_set_wrap(&c, 6000 - 1); gpio_set_function(TRIGOUT_GPIO, GPIO_FUNC_PWM);