#include <stdio.h>

int main(int argc, char** argv)
{
	if (argc != 2) {
		printf("One argument only!\n");
		return -2;
	}
	char tx_buffer[4] = {'A', '5', '3', 0};
	char rx_buffer[512] = {0};
	printf("Trying to open file %s\n", argv[1]);
	FILE* handle = fopen(argv[1], "rb+");
	if (!handle) {
		printf("Failed to open device file!\n");
		return -1;
	}
	fwrite(tx_buffer, 1, 4, handle);
	printf("Sent message: %s\n", tx_buffer);
	fread(rx_buffer, 1, 512, handle);
	printf("Received message: %s\n", rx_buffer);
	fclose(handle);
	return 0;
}