// Copyright (c) 2021 Michael Stoops. All rights reserved.
// Portions copyright (c) 2021 Raspberry Pi (Trading) Ltd.
//
// Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
// following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
// disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
// following disclaimer in the documentation and/or other materials provided with the distribution.
// 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote
// products derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
// USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// SPDX-License-Identifier: BSD-3-Clause
//
// Example of an SPI bus master using the PL022 SPI interface
#include <stdio.h>
#include "pico/stdlib.h"
#include "pico/binary_info.h"
#include "hardware/spi.h"
#define BUF_LEN 0x100
void printbuf(uint8_t buf[], size_t len) {
size_t i;
for (i = 0; i < len; ++i) {
if (i % 16 == 15)
printf("%02x\n", buf[i]);
else
printf("%02x ", buf[i]);
}
// append trailing newline if there isn't one
if (i % 16) {
putchar('\n');
}
}
int main() {
// Enable UART so we can print
stdio_init_all();
#if !defined(spi_default) || !defined(PICO_DEFAULT_SPI_SCK_PIN) || !defined(PICO_DEFAULT_SPI_TX_PIN) || !defined(PICO_DEFAULT_SPI_RX_PIN) || !defined(PICO_DEFAULT_SPI_CSN_PIN)
#warning spi/spi_master example requires a board with SPI pins
puts("Default SPI pins were not defined");
#else
printf("SPI master example\n");
// Enable SPI 0 at 1 MHz and connect to GPIOs
spi_init(spi_default, 1000 * 1000);
gpio_set_function(PICO_DEFAULT_SPI_RX_PIN, GPIO_FUNC_SPI);
gpio_set_function(PICO_DEFAULT_SPI_SCK_PIN, GPIO_FUNC_SPI);
gpio_set_function(PICO_DEFAULT_SPI_TX_PIN, GPIO_FUNC_SPI);
gpio_set_function(PICO_DEFAULT_SPI_CSN_PIN, GPIO_FUNC_SPI);
// Make the SPI pins available to picotool
bi_decl(bi_4pins_with_func(PICO_DEFAULT_SPI_RX_PIN, PICO_DEFAULT_SPI_TX_PIN, PICO_DEFAULT_SPI_SCK_PIN, PICO_DEFAULT_SPI_CSN_PIN, GPIO_FUNC_SPI));
uint8_t out_buf[BUF_LEN], in_buf[BUF_LEN];
// Initialize output buffer
for (size_t i = 0; i < BUF_LEN; ++i) {
out_buf[i] = i;
}
printf("SPI master says: The following buffer will be written to MOSI endlessly:\n");
printbuf(out_buf, BUF_LEN);
for (size_t i = 0; ; ++i) {
// Write the output buffer to MOSI, and at the same time read from MISO.
spi_write_read_blocking(spi_default, out_buf, in_buf, BUF_LEN);
// Write to stdio whatever came in on the MISO line.
printf("SPI master says: read page %d from the MISO line:\n", i);
printbuf(in_buf, BUF_LEN);
// Sleep for ten seconds so you get a chance to read the output.
sleep_ms(10 * 1000);
}
#endif
}