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rp2/modrp2: Support reading the BOOTSEL button on the Pico board.

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And any other board that exposes this pin with a button.
This commit is contained in:
Tomofumi Inoue 2022-08-30 16:03:02 +09:00 committed by Damien George
parent dc2186c35b
commit 673957b643
1 changed files with 53 additions and 0 deletions
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53
ports/rp2/modrp2.c
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@ -27,6 +27,11 @@
#include "py/runtime.h"
#include "drivers/dht/dht.h"
#include "modrp2.h"
#include "pico/stdlib.h"
#include "hardware/gpio.h"
#include "hardware/sync.h"
#include "hardware/structs/ioqspi.h"
#include "hardware/structs/sio.h"
#if MICROPY_PY_NETWORK_CYW43
#include "extmod/modnetwork.h"
@ -36,11 +41,59 @@
MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(mod_network_country_obj);
#endif
// Picoboard has a button attached to the flash CS pin, which the bootrom
// checks, and jumps straight to the USB bootcode if the button is pressed
// (pulling flash CS low). We can check this pin in by jumping to some code in
// SRAM (so that the XIP interface is not required), floating the flash CS
// pin, and observing whether it is pulled low.
//
// This doesn't work if others are trying to access flash at the same time,
// e.g. XIP streamer, or the other core.
// https://github.com/raspberrypi/pico-examples/blob/master/picoboard/button/button.c
bool __no_inline_not_in_flash_func(get_bootsel_button)() {
const uint CS_PIN_INDEX = 1;
// Must disable interrupts, as interrupt handlers may be in flash, and we
// are about to temporarily disable flash access!
uint32_t flags = save_and_disable_interrupts();
// Set chip select to Hi-Z
hw_write_masked(&ioqspi_hw->io[CS_PIN_INDEX].ctrl,
GPIO_OVERRIDE_LOW << IO_QSPI_GPIO_QSPI_SS_CTRL_OEOVER_LSB,
IO_QSPI_GPIO_QSPI_SS_CTRL_OEOVER_BITS);
// Note we can't call into any sleep functions in flash right now
for (volatile int i = 0; i < 1000; ++i) {;
}
// The HI GPIO registers in SIO can observe and control the 6 QSPI pins.
// Note the button pulls the pin *low* when pressed.
bool button_state = !(sio_hw->gpio_hi_in & (1u << CS_PIN_INDEX));
// Need to restore the state of chip select, else we are going to have a
// bad time when we return to code in flash!
hw_write_masked(&ioqspi_hw->io[CS_PIN_INDEX].ctrl,
GPIO_OVERRIDE_NORMAL << IO_QSPI_GPIO_QSPI_SS_CTRL_OEOVER_LSB,
IO_QSPI_GPIO_QSPI_SS_CTRL_OEOVER_BITS);
restore_interrupts(flags);
return button_state;
}
STATIC mp_obj_t rp2_bootsel_button(void) {
return MP_OBJ_NEW_SMALL_INT(get_bootsel_button());
}
MP_DEFINE_CONST_FUN_OBJ_0(rp2_bootsel_button_obj, rp2_bootsel_button);
STATIC const mp_rom_map_elem_t rp2_module_globals_table[] = {
{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_rp2) },
{ MP_ROM_QSTR(MP_QSTR_Flash), MP_ROM_PTR(&rp2_flash_type) },
{ MP_ROM_QSTR(MP_QSTR_PIO), MP_ROM_PTR(&rp2_pio_type) },
{ MP_ROM_QSTR(MP_QSTR_StateMachine), MP_ROM_PTR(&rp2_state_machine_type) },
{ MP_ROM_QSTR(MP_QSTR_bootsel_button), MP_ROM_PTR(&rp2_bootsel_button_obj) },
#if MICROPY_PY_NETWORK_CYW43
// Deprecated (use network.country instead).