155 lines
4.1 KiB
C
155 lines
4.1 KiB
C
/**
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* Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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// Example of reading/writing an external serial flash using the PL022 SPI interface
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#include <stdio.h>
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#include "pico/stdlib.h"
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#include "hardware/spi.h"
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#define FLASH_PAGE_SIZE 256
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#define FLASH_SECTOR_SIZE 4096
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#define FLASH_CMD_PAGE_PROGRAM 0x02
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#define FLASH_CMD_READ 0x03
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#define FLASH_CMD_STATUS 0x05
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#define FLASH_CMD_WRITE_EN 0x06
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#define FLASH_CMD_SECTOR_ERASE 0x20
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#define FLASH_STATUS_BUSY_MASK 0x01
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#define PIN_MISO 4
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#define PIN_CS 5
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#define PIN_SCK 6
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#define PIN_MOSI 7
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static inline void cs_select(uint cs_pin) {
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asm volatile("nop \n nop \n nop"); // FIXME
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gpio_put(cs_pin, 0);
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asm volatile("nop \n nop \n nop"); // FIXME
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}
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static inline void cs_deselect(uint cs_pin) {
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asm volatile("nop \n nop \n nop"); // FIXME
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gpio_put(cs_pin, 1);
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asm volatile("nop \n nop \n nop"); // FIXME
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}
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void __not_in_flash_func(flash_read)(spi_inst_t *spi, uint cs_pin, uint32_t addr, uint8_t *buf, size_t len) {
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cs_select(cs_pin);
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uint8_t cmdbuf[4] = {
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FLASH_CMD_READ,
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addr >> 16,
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addr >> 8,
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addr
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};
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spi_write_blocking(spi, cmdbuf, 4);
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spi_read_blocking(spi, 0, buf, len);
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cs_deselect(cs_pin);
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}
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void __not_in_flash_func(flash_write_enable)(spi_inst_t *spi, uint cs_pin) {
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cs_select(cs_pin);
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uint8_t cmd = FLASH_CMD_WRITE_EN;
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spi_write_blocking(spi, &cmd, 1);
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cs_deselect(cs_pin);
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}
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void __not_in_flash_func(flash_wait_done)(spi_inst_t *spi, uint cs_pin) {
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uint8_t status;
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do {
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cs_select(cs_pin);
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uint8_t buf[2] = {FLASH_CMD_STATUS, 0};
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spi_write_read_blocking(spi, buf, buf, 2);
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cs_deselect(cs_pin);
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status = buf[1];
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} while (status & FLASH_STATUS_BUSY_MASK);
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}
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void __not_in_flash_func(flash_sector_erase)(spi_inst_t *spi, uint cs_pin, uint32_t addr) {
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uint8_t cmdbuf[4] = {
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FLASH_CMD_SECTOR_ERASE,
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addr >> 16,
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addr >> 8,
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addr
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};
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flash_write_enable(spi, cs_pin);
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cs_select(cs_pin);
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spi_write_blocking(spi, cmdbuf, 4);
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cs_deselect(cs_pin);
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flash_wait_done(spi, cs_pin);
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}
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void __not_in_flash_func(flash_page_program)(spi_inst_t *spi, uint cs_pin, uint32_t addr, uint8_t data[]) {
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uint8_t cmdbuf[4] = {
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FLASH_CMD_PAGE_PROGRAM,
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addr >> 16,
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addr >> 8,
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addr
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};
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flash_write_enable(spi, cs_pin);
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cs_select(cs_pin);
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spi_write_blocking(spi, cmdbuf, 4);
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spi_write_blocking(spi, data, FLASH_PAGE_SIZE);
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cs_deselect(cs_pin);
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flash_wait_done(spi, cs_pin);
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}
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void printbuf(uint8_t buf[FLASH_PAGE_SIZE]) {
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for (int i = 0; i < FLASH_PAGE_SIZE; ++i) {
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if (i % 16 == 15)
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printf("%02x\n", buf[i]);
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else
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printf("%02x ", buf[i]);
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}
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}
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int main() {
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// Enable UART so we can print status output
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stdio_init_all();
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printf("SPI flash example\n");
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// Enable SPI 0 at 1 MHz and connect to GPIOs
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spi_init(spi0, 1000 * 1000);
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gpio_set_function(PIN_MISO, GPIO_FUNC_SPI);
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gpio_set_function(PIN_SCK, GPIO_FUNC_SPI);
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gpio_set_function(PIN_MOSI, GPIO_FUNC_SPI);
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// Chip select is active-low, so we'll initialise it to a driven-high state
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gpio_init(PIN_CS);
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gpio_put(PIN_CS, 1);
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gpio_set_dir(PIN_CS, GPIO_OUT);
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printf("SPI initialised, let's goooooo\n");
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uint8_t page_buf[FLASH_PAGE_SIZE];
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const uint32_t target_addr = 0;
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flash_sector_erase(spi0, PIN_CS, target_addr);
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flash_read(spi0, PIN_CS, target_addr, page_buf, FLASH_PAGE_SIZE);
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printf("After erase:\n");
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printbuf(page_buf);
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for (int i = 0; i < FLASH_PAGE_SIZE; ++i)
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page_buf[i] = i;
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flash_page_program(spi0, PIN_CS, target_addr, page_buf);
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flash_read(spi0, PIN_CS, target_addr, page_buf, FLASH_PAGE_SIZE);
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printf("After program:\n");
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printbuf(page_buf);
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flash_sector_erase(spi0, PIN_CS, target_addr);
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flash_read(spi0, PIN_CS, target_addr, page_buf, FLASH_PAGE_SIZE);
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printf("Erase again:\n");
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printbuf(page_buf);
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return 0;
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}
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