10000 machine: Add time_hardware_pulse_us function. · micropython/micropython@7a9b45d · GitHub
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IhorNehrutsaIhorNehrutsa
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machine: Add time_hardware_pulse_us function.
The difference from `time_pulse_us` is that if the pin is initially equal to *pulse_level* then `time_pulse_us` counts the pulse duration immediately, but `time_hardware_pulse_us` first waits for the different *pulse_level*, then waits the equal to *pulse_level* and then counts pulse duration. Signed-off-by: IhorNehrutsa <Ihor.Nehrutsa@gmail.com>
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‎docs/library/machine.rst

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@@ -198,6 +198,29 @@ Miscellaneous functions
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above. The timeout is the same for both cases and given by *timeout_us* (which
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is in microseconds).
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.. function:: time_hardware_pulse_us(pin, pulse_level, timeout_us=1000000, /)
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Time a pulse on the given *pin*, and return the duration of the pulse in
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microseconds. The *pulse_level* argument should be 0 to time a low pulse
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or 1 to time a high pulse.
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If the pin is initially equal to *pulse_level* then first waits until
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the pin input becomes different from *pulse_level* (***).
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Then the function waits until the pin input becomes equal to *pulse_level* (**),
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then the function counts the duration that the pin is equal to *pulse_level* (*).
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The function returns -3 if there was timeout waiting for condition marked (***) above.
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The function will return -2 if there was timeout waiting for condition marked
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(**) above, and -1 if there was timeout during the main measurement, marked (*)
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above. The timeout is the same for all cases and given by *timeout_us* (which
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is in microseconds).
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The difference from `time_pulse_us` is that if the pin is initially equal to *pulse_level*
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then `time_pulse_us` counts the pulse duration immediately,
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but `time_hardware_pulse_us` first waits for the different *pulse_level*,
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then waits the equal to *pulse_level* and then counts pulse duration.
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A little bit longer, but higher accuracy.
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.. function:: bitstream(pin, encoding, timing, data, /)
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Transmits *data* by bit-banging the specified *pin*. The *encoding* argument

‎extmod/machine_pulse.c

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@@ -62,4 +62,42 @@ static mp_obj_t machine_time_pulse_us_(size_t n_args, const mp_obj_t *args) {
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}
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MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_time_pulse_us_obj, 2, 3, machine_time_pulse_us_);
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MP_WEAK mp_uint_t machine_time_hardware_pulse_us(mp_hal_pin_obj_t pin, int pulse_level, mp_uint_t timeout_us) {
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mp_uint_t start = mp_hal_ticks_us();
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while (mp_hal_pin_read(pin) == pulse_level) {
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if ((mp_uint_t)(mp_hal_ticks_us() - start) >= timeout_us) {
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return (mp_uint_t)-3;
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}
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}
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start = mp_hal_ticks_us();
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while (mp_hal_pin_read(pin) != pulse_level) {
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if ((mp_uint_t)(mp_hal_ticks_us() - start) >= timeout_us) {
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return (mp_uint_t)-2;
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}
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}
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start = mp_hal_ticks_us();
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while (mp_hal_pin_read(pin) == pulse_level) {
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if ((mp_uint_t)(mp_hal_ticks_us() - start) >= timeout_us) {
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return (mp_uint_t)-1;
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}
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}
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return mp_hal_ticks_us() - start;
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}
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static mp_obj_t machine_time_hardware_pulse_us_(size_t n_args, const mp_obj_t *args) {
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mp_hal_pin_obj_t pin = mp_hal_get_pin_obj(args[0]);
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int level = 0;
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if (mp_obj_is_true(args[1])) {
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level = 1;
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}
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mp_uint_t timeout_us = 1000000;
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if (n_args > 2) {
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timeout_us = mp_obj_get_int(args[2]);
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}
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mp_uint_t us = machine_time_hardware_pulse_us(pin, level, timeout_us);
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// May return -1 or -2 or -3 in case of timeout
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return mp_obj_new_int(us);
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}
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MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_time_hardware_pulse_us_obj, 2, 3, machine_time_hardware_pulse_us_);
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#endif

‎extmod/modmachine.c

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@@ -188,6 +188,7 @@ static const mp_rom_map_elem_t machine_module_globals_table[] = {
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#endif
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#if MICROPY_PY_MACHINE_PULSE
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{ MP_ROM_QSTR(MP_QSTR_time_pulse_us), MP_ROM_PTR(&machine_time_pulse_us_obj) },
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{ MP_ROM_QSTR(MP_QSTR_time_hardware_pulse_us), MP_ROM_PTR(&machine_time_hardware_pulse_us_obj) },
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#endif
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// Classes for PinBase and Signal.

‎extmod/modmachine.h

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@@ -255,6 +255,7 @@ MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(machine_deepsleep_obj);
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MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(machine_bootloader_obj);
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MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(machine_bitstream_obj);
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MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(machine_time_pulse_us_obj);
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MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(machine_time_hardware_pulse_us_obj);
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#if MICROPY_PY_MACHINE_I2C
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int mp_machine_i2c_transfer_adaptor(mp_obj_base_t *self, uint16_t addr, size_t n, mp_machine_i2c_buf_t *bufs, unsigned int flags);

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