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esp32/machine_sdcard: Add "freq" keyword arg to SDCard constructor.

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To allow high speed access.
This commit is contained in:
cccc 2020-02-25 23:09:59 +08:00 committed by Damien George
parent 2d1fef7096
commit 1662a0b06f
2 changed files with 9 additions and 1 deletions
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4
docs/library/machine.SDCard.rst
View File

@ -23,7 +23,7 @@ arguments that might need to be set in order to use either a non-standard slot
or a non-standard pin assignment. The exact subset of arguments supported will
vary from platform to platform.
.. class:: SDCard(slot=1, width=1, cd=None, wp=None, sck=None, miso=None, mosi=None, cs=None)
.. class:: SDCard(slot=1, width=1, cd=None, wp=None, sck=None, miso=None, mosi=None, cs=None, freq=20000000)
This class provides access to SD or MMC storage cards using either
a dedicated SD/MMC interface hardware or through an SPI channel.
@ -50,6 +50,8 @@ vary from platform to platform.
- *mosi* can be used to specify an SPI mosi pin.
- *cs* can be used to specify an SPI chip select pin.
- *freq* selects the SD/MMC interface frequency in Hz (only supported on the ESP32).
Implementation-specific details
-------------------------------

6
ports/esp32/machine_sdcard.c
View File

@ -126,6 +126,7 @@ STATIC mp_obj_t machine_sdcard_make_new(const mp_obj_type_t *type, size_t n_args
ARG_mosi,
ARG_sck,
ARG_cs,
ARG_freq,
};
STATIC const mp_arg_t allowed_args[] = {
{ MP_QSTR_slot, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 1} },
@ -137,6 +138,8 @@ STATIC mp_obj_t machine_sdcard_make_new(const mp_obj_type_t *type, size_t n_args
{ MP_QSTR_mosi, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
{ MP_QSTR_sck, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
{ MP_QSTR_cs, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
// freq is valid for both SPI and SDMMC interfaces
{ MP_QSTR_freq, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 20000000} },
};
mp_arg_val_t arg_vals[MP_ARRAY_SIZE(allowed_args)];
mp_map_t kw_args;
@ -175,11 +178,14 @@ STATIC mp_obj_t machine_sdcard_make_new(const mp_obj_type_t *type, size_t n_args
self->flags = 0;
// Note that these defaults are macros that expand to structure
// constants so we can't directly assign them to fields.
int freq = arg_vals[ARG_freq].u_int;
if (is_spi) {
sdmmc_host_t _temp_host = SDSPI_HOST_DEFAULT();
_temp_host.max_freq_khz = freq / 1000;
self->host = _temp_host;
} else {
sdmmc_host_t _temp_host = SDMMC_HOST_DEFAULT();
_temp_host.max_freq_khz = freq / 1000;
self->host = _temp_host;
}