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drivers/memory: Add SPI flash driver, written in C.
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‎drivers/memory/spiflash.c‎

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/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2016-2017 Damien P. George
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <stdio.h>
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#include <string.h>
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#include "py/mperrno.h"
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#include "py/mphal.h"
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#include "extmod/machine_spi.h"
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#include "drivers/memory/spiflash.h"
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#define CMD_WRITE (0x02)
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#define CMD_READ (0x03)
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#define CMD_WRDI (0x04)
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#define CMD_RDSR (0x05)
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#define CMD_WREN (0x06)
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#define CMD_SEC_ERASE (0x20)
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#define WAIT_SR_TIMEOUT (1000000)
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#define PAGE_SIZE (256) // maximum bytes we can write in one SPI transfer
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#define SECTOR_SIZE (4096) // size of erase sector
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// Note: this code is not reentrant with this shared buffer
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STATIC uint8_t buf[SECTOR_SIZE];
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void mp_spiflash_init(mp_spiflash_t *self) {
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mp_hal_pin_write(self->cs, 1);
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mp_hal_pin_output(self->cs);
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mp_hal_pin_write(self->spi.sck, 0);
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mp_hal_pin_output(self->spi.sck);
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mp_hal_pin_output(self->spi.mosi);
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mp_hal_pin_input(self->spi.miso);
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}
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STATIC void mp_spiflash_acquire_bus(mp_spiflash_t *self) {
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// can be used for actions needed to acquire bus
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(void)self;
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}
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STATIC void mp_spiflash_release_bus(mp_spiflash_t *self) {
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// can be used for actions needed to release bus
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(void)self;
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}
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STATIC void mp_spiflash_transfer(mp_spiflash_t *self, size_t len, const uint8_t *src, uint8_t *dest) {
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mp_machine_soft_spi_transfer(&self->spi.base, len, src, dest);
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}
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STATIC int mp_spiflash_wait_sr(mp_spiflash_t *self, uint8_t mask, uint8_t val, uint32_t timeout) {
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uint8_t cmd[1] = {CMD_RDSR};
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mp_hal_pin_write(self->cs, 0);
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mp_spiflash_transfer(self, 1, cmd, NULL);
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for (; timeout; --timeout) {
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mp_spiflash_transfer(self, 1, cmd, cmd);
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if ((cmd[0] & mask) == val) {
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break;
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}
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}
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mp_hal_pin_write(self->cs, 1);
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if ((cmd[0] & mask) == val) {
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return 0; // success
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} else if (timeout == 0) {
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return -MP_ETIMEDOUT;
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} else {
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return -MP_EIO;
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}
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}
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STATIC int mp_spiflash_wait_wel1(mp_spiflash_t *self) {
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return mp_spiflash_wait_sr(self, 2, 2, WAIT_SR_TIMEOUT);
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}
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STATIC int mp_spiflash_wait_wip0(mp_spiflash_t *self) {
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return mp_spiflash_wait_sr(self, 1, 0, WAIT_SR_TIMEOUT);
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}
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STATIC void mp_spiflash_write_cmd(mp_spiflash_t *self, uint8_t cmd) {
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mp_hal_pin_write(self->cs, 0);
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mp_spiflash_transfer(self, 1, &cmd, NULL);
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mp_hal_pin_write(self->cs, 1);
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}
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STATIC int mp_spiflash_erase_sector(mp_spiflash_t *self, uint32_t addr) {
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// enable writes
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mp_spiflash_write_cmd(self, CMD_WREN);
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// wait WEL=1
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int ret = mp_spiflash_wait_wel1(self);
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if (ret != 0) {
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return ret;
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}
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// erase the sector
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mp_hal_pin_write(self->cs, 0);
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uint8_t cmd[4] = {CMD_SEC_ERASE, addr >> 16, addr >> 8, addr};
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mp_spiflash_transfer(self, 4, cmd, NULL);
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mp_hal_pin_write(self->cs, 1);
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// wait WIP=0
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return mp_spiflash_wait_wip0(self);
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}
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STATIC int mp_spiflash_write_page(mp_spiflash_t *self, uint32_t addr, const uint8_t *src) {
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// enable writes
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mp_spiflash_write_cmd(self, CMD_WREN);
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// wait WEL=1
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int ret = mp_spiflash_wait_wel1(self);
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if (ret != 0) {
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return ret;
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}
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// write the page
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mp_hal_pin_write(self->cs, 0);
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uint8_t cmd[4] = {CMD_WRITE, addr >> 16, addr >> 8, addr};
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mp_spiflash_transfer(self, 4, cmd, NULL);
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mp_spiflash_transfer(self, PAGE_SIZE, src, NULL);
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mp_hal_pin_write(self->cs, 1);
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// wait WIP=0
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return mp_spiflash_wait_wip0(self);
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}
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void mp_spiflash_read(mp_spiflash_t *self, uint32_t addr, size_t len, uint8_t *dest) {
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mp_spiflash_acquire_bus(self);
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uint8_t cmd[4] = {CMD_READ, addr >> 16, addr >> 8, addr};
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mp_hal_pin_write(self->cs, 0);
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mp_spiflash_transfer(self, 4, cmd, NULL);
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mp_spiflash_transfer(self, len, dest, dest);
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mp_hal_pin_write(self->cs, 1);
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mp_spiflash_release_bus(self);
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}
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int mp_spiflash_write(mp_spiflash_t *self, uint32_t addr, size_t len, const uint8_t *src) {
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// TODO optimise so we don't need to erase multiple times for successive writes to a sector
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// align to 4096 sector
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uint32_t offset = addr & 0xfff;
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addr = (addr >> 12) << 12;
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// restriction for now, so we don't need to erase multiple pages
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if (offset + len > sizeof(buf)) {
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printf("mp_spiflash_write: len is too large\n");
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return -MP_EIO;
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}
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mp_spiflash_acquire_bus(self);
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// read sector
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uint8_t cmd[4] = {CMD_READ, addr >> 16, addr >> 8, addr};
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mp_hal_pin_write(self->cs, 0);
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mp_spiflash_transfer(self, 4, cmd, NULL);
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mp_spiflash_transfer(self, SECTOR_SIZE, buf, buf);
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mp_hal_pin_write(self->cs, 1);
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// erase sector
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int ret = mp_spiflash_erase_sector(self, addr);
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if (ret != 0) {
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mp_spiflash_release_bus(self);
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return ret;
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}
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// copy new block into buffer
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memcpy(buf + offset, src, len);
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// write sector in pages of 256 bytes
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for (int i = 0; i < SECTOR_SIZE; i += 256) {
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ret = mp_spiflash_write_page(self, addr + i, buf + i);
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if (ret != 0) {
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mp_spiflash_release_bus(self);
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return ret;
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}
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}
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mp_spiflash_release_bus(self);
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return 0; // success
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}

‎drivers/memory/spiflash.h‎

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/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2016 Damien P. George
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
9+
* of this software and associated documentation files (the "Software"), to deal
10+
* in the Software without restriction, including without limitation the rights
11+
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12+
* copies of the Software, and to permit persons to whom the Software is
13+
* furnished to do so, subject to the following conditions:
14+
*
15+
* The above copyright notice and this permission notice shall be included in
16+
* all copies or substantial portions of the Software.
17+
*
18+
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19+
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20+
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21+
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22+
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifndef MICROPY_INCLUDED_DRIVERS_MEMORY_SPIFLASH_H
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#define MICROPY_INCLUDED_DRIVERS_MEMORY_SPIFLASH_H
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#include "extmod/machine_spi.h"
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typedef struct _mp_spiflash_t {
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mp_hal_pin_obj_t cs;
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// TODO replace with generic SPI object
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mp_machine_soft_spi_obj_t spi;
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} mp_spiflash_t;
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void mp_spiflash_init(mp_spiflash_t *self);
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void mp_spiflash_read(mp_spiflash_t *self, uint32_t addr, size_t len, uint8_t *dest);
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int mp_spiflash_write(mp_spiflash_t *self, uint32_t addr, size_t len, const uint8_t *src);
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#endif // MICROPY_INCLUDED_DRIVERS_MEMORY_SPIFLASH_H

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