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espressif: Correct comments on IncrementalEncoder

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Jeff Epler 2023-12-22 08:57:32 -06:00
parent 5aa203f13e
commit f8c5aabc83
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1 changed files with 13 additions and 4 deletions
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17
ports/espressif/common-hal/rotaryio/IncrementalEncoder.c
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@ -35,6 +35,15 @@ void common_hal_rotaryio_incrementalencoder_construct(rotaryio_incrementalencode
claim_pin(pin_a);
claim_pin(pin_b);
// This configuration counts on all edges of the quadrature signal: Channel 0
// counts on rising and falling edges of channel A, with the direction set by the
// polarity of channel B. Channel 1 does likewise, counting edges of channel B according
// to the polarity of channel A. A little pencil work suffices to show that this
// counts correctly on all 8 correct quadrature state transitions.
//
// These routines also implicitly configure the weak internal pull-ups, as expected
// in CircuitPython.
// Prepare configuration for the PCNT unit
pcnt_config_t pcnt_config_channel_0 = {
// Set PCNT input signal and control GPIOs
@ -42,8 +51,8 @@ void common_hal_rotaryio_incrementalencoder_construct(rotaryio_incrementalencode
.ctrl_gpio_num = pin_b->number,
.channel = PCNT_CHANNEL_0,
// What to do on the positive / negative edge of pulse input?
.pos_mode = PCNT_COUNT_DEC, // Count up on the positive edge
.neg_mode = PCNT_COUNT_INC, // Keep the counter value on the negative edge
.pos_mode = PCNT_COUNT_DEC, // Count down on the positive edge
.neg_mode = PCNT_COUNT_INC, // Count up on negative edge
// What to do when control input is low or high?
.lctrl_mode = PCNT_MODE_REVERSE, // Reverse counting direction if low
.hctrl_mode = PCNT_MODE_KEEP, // Keep the primary counter mode if high
@ -61,8 +70,8 @@ void common_hal_rotaryio_incrementalencoder_construct(rotaryio_incrementalencode
.ctrl_gpio_num = pin_a->number,
.channel = PCNT_CHANNEL_1,
// What to do on the positive / negative edge of pulse input?
.pos_mode = PCNT_COUNT_DEC, // Count up on the positive edge
.neg_mode = PCNT_COUNT_INC, // Keep the counter value on the negative edge
.pos_mode = PCNT_COUNT_DEC, // Count down on the positive edge
.neg_mode = PCNT_COUNT_INC, // Count up on negative edge
// What to do when control input is low or high?
.lctrl_mode = PCNT_MODE_KEEP, // Keep the primary counter mode if low
.hctrl_mode = PCNT_MODE_REVERSE, // Reverse counting direction if high