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This application continuously reads the file system of the spislv. Each received message will be written to the user in hexadecimal form, and the same received data will be sent back. In this way, the user can test if their spislv driver and hardware setup are working properly before proceeding further. On a master device, using the SPI tool, when sending the message: spi exch -x 4 deadbeef The slave device will output: Slave: 4 Bytes read Value in hex form from /dev/spislv2: de ad be ef Slave: Writing value back to /dev/spislv2
103 lines
3.1 KiB
C
103 lines
3.1 KiB
C
/****************************************************************************
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* apps/examples/spislv_test/spislv_test.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdio.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <errno.h>
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#include <string.h>
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#include <stdlib.h>
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#define SOURCE_FILE "/dev/spislv2"
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#define BUFFER_SIZE 256
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* spislv_test
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****************************************************************************/
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int main(int argc, FAR char *argv[])
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{
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int fd;
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char buffer[BUFFER_SIZE];
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ssize_t bytes_read;
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ssize_t i;
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printf("Slave started!!\n");
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fd = open(SOURCE_FILE, O_RDWR);
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if (fd < 0)
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{
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printf("Failed to open %s: %s\n", SOURCE_FILE, strerror(errno));
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return 0;
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}
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while (1)
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{
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/* Read the number from the source file */
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printf("Slave: Reading from %s\n", SOURCE_FILE);
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bytes_read = read(fd, buffer, BUFFER_SIZE - 1);
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if (bytes_read < 0)
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{
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printf("Failed to read from %s: %s\n",
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SOURCE_FILE, strerror(errno));
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close(fd);
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return 0;
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}
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else if (bytes_read > 0)
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{
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buffer[bytes_read] = '\0';
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/* Print buffer in hexadecimal format */
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printf("Slave: Read value in hex: ");
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for (i = 0; i < bytes_read; ++i)
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{
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printf("%02x ", (unsigned char)buffer[i]);
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}
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printf("\n");
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/* Write the same value back */
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printf("Slave: Writing %d bytes back to %s\n",
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bytes_read, SOURCE_FILE);
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ssize_t bytes_written = write(fd, buffer, bytes_read);
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if (bytes_written < 0)
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{
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printf("Failed to write to %s: %s\n",
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SOURCE_FILE, strerror(errno));
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close(fd);
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return 0;
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}
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}
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}
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}
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