8000 rp2/machine_spi: Allow MISO to be unspecified. · micropython/micropython@dd7a950 · GitHub
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Gadgetoiddpgeorge
Gadgetoid
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dpgeorge
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rp2/machine_spi: Allow MISO to be unspecified.
It's common with write-only SPI displays for MISO to be repurposed as a register select or data/command pin. While that was possible by setting up the pin after a call to `machine.SPI()` this change makes `machine.SPI(miso=None)` explicit. Signed-off-by: Phil Howard <github@gadgetoid.com>
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‎ports/rp2/machine_spi.c

Lines changed: 18 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -80,6 +80,9 @@
8080

8181
#endif
8282

83+
// Assume we won't get an RP2-compatible with 255 GPIO pins
84+
#define MICROPY_HW_SPI_PIN_UNUSED UINT8_MAX
85+
8386
// SPI0 can be GP{0..7,16..23}, SPI1 can be GP{8..15,24..29}.
8487
#define IS_VALID_PERIPH(spi, pin) ((((pin) & 8) >> 3) == (spi))
8588
// GP{2,6,10,14,...}
@@ -120,9 +123,14 @@ static machine_spi_obj_t machine_spi_obj[] = {
120123

121124
static void machine_spi_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
122125
machine_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);
123-
mp_printf(print, "SPI(%u, baudrate=%u, polarity=%u, phase=%u, bits=%u, sck=%u, mosi=%u, miso=%u)",
126+
mp_printf(print, "SPI(%u, baudrate=%u, polarity=%u, phase=%u, bits=%u, sck=%u, mosi=%u, miso=",
124127
self->spi_id, self->baudrate, self->polarity, self->phase, self->bits,
125-
self->sck, self->mosi, self->miso);
128+
self->sck, self->mosi);
129+
if (self->miso == MICROPY_HW_SPI_PIN_UNUSED) {
130+
mp_printf(print, "None)");
131+
} else {
132+
mp_printf(print, "%u)", self->miso);
133+
}
126134
}
127135

128136
mp_obj_t machine_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
@@ -140,7 +148,7 @@ mp_obj_t machine_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n
140148
{ MP_QSTR_firstbit, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_SPI_FIRSTBIT} },
141149
{ MP_QSTR_sck, MICROPY_SPI_PINS_ARG_OPTS | MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
142150
{ MP_QSTR_mosi, MICROPY_SPI_PINS_ARG_OPTS | MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
143-
{ MP_QSTR_miso, MICROPY_SPI_PINS_ARG_OPTS | MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
151+
{ MP_QSTR_miso, MICROPY_SPI_PINS_ARG_OPTS | MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_INT(-1)} },
144152
};
145153

146154
// Parse the arguments.
@@ -171,7 +179,10 @@ mp_obj_t machine_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n
171179
}
172180
self->mosi = mosi;
173181
}
174-
if (args[ARG_miso].u_obj != mp_const_none) {
182+
183+
if (args[ARG_miso].u_obj == mp_const_none) {
184+
self->miso = MICROPY_HW_SPI_PIN_UNUSED;
185+
} else if (args[ARG_miso].u_obj != MP_OBJ_NEW_SMALL_INT(-1)) {
175186
int miso = mp_hal_get_pin_obj(args[ARG_miso].u_obj);
176187
if (!IS_VALID_MISO(self->spi_id, miso)) {
177188
mp_raise_ValueError(MP_ERROR_TEXT("bad MISO pin"));
@@ -194,7 +205,9 @@ mp_obj_t machine_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n
194205
self->baudrate = spi_set_baudrate(self->spi_inst, self->baudrate);
195206
spi_set_format(self->spi_inst, self->bits, self->polarity, self->phase, self->firstbit);
196207
gpio_set_function(self->sck, GPIO_FUNC_SPI);
197-
gpio_set_function(self->miso, GPIO_FUNC_SPI);
208+
if (self->miso != MICROPY_HW_SPI_PIN_UNUSED) {
209+
gpio_set_function(self->miso, GPIO_FUNC_SPI);
210+
}
198211
gpio_set_function(self->mosi, GPIO_FUNC_SPI);
199212
}
200213

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