91 lines
3.8 KiB
C
91 lines
3.8 KiB
C
// 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 slave using the PL022 SPI interface
|
|
|
|
#include <stdio.h>
|
|
#include <string.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) {
|
|
int 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_slave example requires a board with SPI pins
|
|
puts("Default SPI pins were not defined");
|
|
#else
|
|
|
|
printf("SPI slave example\n");
|
|
|
|
// Enable SPI 0 at 1 MHz and connect to GPIOs
|
|
spi_init(spi_default, 1000 * 1000);
|
|
spi_set_slave(spi_default, true);
|
|
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) {
|
|
// bit-inverted from i. The values should be: {0xff, 0xfe, 0xfd...}
|
|
out_buf[i] = ~i;
|
|
}
|
|
|
|
printf("SPI slave says: When reading from MOSI, the following buffer will be written to MISO:\n");
|
|
printbuf(out_buf, BUF_LEN);
|
|
|
|
for (size_t i = 0; ; ++i) {
|
|
// Write the output buffer to MISO, and at the same time read from MOSI.
|
|
spi_write_read_blocking(spi_default, out_buf, in_buf, BUF_LEN);
|
|
|
|
// Write to stdio whatever came in on the MOSI line.
|
|
printf("SPI slave says: read page %d from the MOSI line:\n", i);
|
|
printbuf(in_buf, BUF_LEN);
|
|
}
|
|
#endif
|
|
}
|