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docs/library/pyb.DAC.rst: Correct frequency for triangle mode output. 

Also correct comments in related code.
This commit is contained in:
Jim Mussared 2019-09-03 13:05:10 +10:00 committed by Damien George
parent 50482cdc0c
commit 74fe841449
2 changed files with 6 additions and 6 deletions
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6
docs/library/pyb.DAC.rst
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@ -93,9 +93,9 @@ Methods
.. method:: DAC.triangle(freq)
Generate a triangle wave. The value on the DAC output changes at
the given frequency, and the frequency of the repeating triangle wave
itself is 2048 times smaller.
Generate a triangle wave. The value on the DAC output changes at the given
frequency and ramps through the full 12-bit range (up and down). Therefore
the frequency of the repeating triangle wave itself is 8192 times smaller.
.. method:: DAC.write(value)

6
ports/stm32/dac.c
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@ -373,15 +373,15 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_dac_noise_obj, pyb_dac_noise);
#if defined(TIM6)
/// \method triangle(freq)
/// Generate a triangle wave. The value on the DAC output changes at
/// the given frequency, and the frequence of the repeating triangle wave
/// itself is 256 (or 1024, need to check) times smaller.
/// the given frequency, and the frequency of the repeating triangle wave
/// itself is 8192 times smaller.
STATIC mp_obj_t pyb_dac_triangle(mp_obj_t self_in, mp_obj_t freq) {
pyb_dac_obj_t *self = MP_OBJ_TO_PTR(self_in);
// set TIM6 to trigger the DAC at the given frequency
TIM6_Config(mp_obj_get_int(freq));
// Configure DAC in triangle mode with trigger via TIM6
// Configure DAC in full-scale triangle mode with trigger via TIM6
uint32_t cr = DAC_TRIANGLEAMPLITUDE_4095 | DAC_CR_WAVE1_1 | DAC_TRIGGER_T6_TRGO;
pyb_dac_reconfigure(self, cr, self->outbuf_waveform, 0);