用于測試樹莓派的SPI接口是否正常工作，代碼來自于

https://raw.githubusercontent.com/raspberrypi/Linux/rpi-3.10.y/Documentation/spi/spidev_test.c

測試方法參考自：http://louisthiery.com/spi-Python-hardware-spi-for-raspi/

/*

*?SPI?testing?utility?(using?spidev?driver)

*

*?Copyright?(c)?2007??MontaVista?Software,?Inc.

*?Copyright?(c)?2007??Anton?Vorontsov?

*

*?This?program?is?free?software;?you?can?redistribute?it?and/or?modify

*?it?under?the?terms?of?the?GNU?General?Public?License?as?published?by

*?the?Free?Software?Foundation;?either?version?2?of?the?License.

*

*?Cross-compile?with?cross-gcc?-I/path/to/cross-kernel/include

*/

#include?

#include?

#include?

#include?

#include?

#include?

#include?

#include?

#include?

#define?ARRAY_SIZE(a)?(sizeof(a)?/?sizeof((a)[0]))

static?void?pabort(const?char?*s)

{

perror(s);

abort();

}

static?const?char?*device?=?"/dev/spidev1.1";

static?uint8_t?mode;

static?uint8_t?bits?=?8;

static?uint32_t?speed?=?500000;

static?uint16_t?delay;

static?void?transfer(int?fd)

{

int?ret;

uint8_t?tx[]?=?{

0xFF,?0xFF,?0xFF,?0xFF,?0xFF,?0xFF,

0x40,?0x00,?0x00,?0x00,?0x00,?0x95,

0xFF,?0xFF,?0xFF,?0xFF,?0xFF,?0xFF,

0xFF,?0xFF,?0xFF,?0xFF,?0xFF,?0xFF,

0xFF,?0xFF,?0xFF,?0xFF,?0xFF,?0xFF,

0xDE,?0xAD,?0xBE,?0xEF,?0xBA,?0xAD,

0xF0,?0x0D,

};

uint8_t?rx[ARRAY_SIZE(tx)]?=?{0,?};

struct?spi_ioc_transfer?tr?=?{

.tx_buf?=?(unsigned?long)tx,

.rx_buf?=?(unsigned?long)rx,

.len?=?ARRAY_SIZE(tx),

.delay_usecs?=?delay,

.speed_hz?=?speed,

.bits_per_word?=?bits,

};

ret?=?ioctl(fd,?SPI_IOC_MESSAGE(1),?&tr);

if?(ret?

pabort("can't?send?spi?message");

for?(ret?=?0;?ret?

if?(!(ret?%?6))

puts("");

printf("%.2X?",?rx[ret]);

}

puts("");

}

static?void?print_usage(const?char?*prog)

{

printf("Usage:?%s?[-DsbdlHOLC3]\n",?prog);

puts("??-D?--device???device?to?use?(default?/dev/spidev1.1)\n"

"??-s?--speed????max?speed?(Hz)\n"

"??-d?--delay????delay?(usec)\n"

"??-b?--bpw??????bits?per?word?\n"

"??-l?--loop?????loopback\n"

"??-H?--cpha?????clock?phase\n"

"??-O?--cpol?????clock?polarity\n"

"??-L?--lsb??????least?significant?bit?first\n"

"??-C?--cs-high??chip?select?active?high\n"

"??-3?--3wire????SI/SO?signals?shared\n");

exit(1);

}

static?void?parse_opts(int?argc,?char?*argv[])

{

while?(1)?{

static?const?struct?option?lopts[]?=?{

{?"device",??1,?0,?'D'?},

{?"speed",???1,?0,?'s'?},

{?"delay",???1,?0,?'d'?},

{?"bpw",?????1,?0,?'b'?},

{?"loop",????0,?0,?'l'?},

{?"cpha",????0,?0,?'H'?},

{?"cpol",????0,?0,?'O'?},

{?"lsb",?????0,?0,?'L'?},

{?"cs-high",?0,?0,?'C'?},

{?"3wire",???0,?0,?'3'?},

{?"no-cs",???0,?0,?'N'?},

{?"ready",???0,?0,?'R'?},

{?NULL,?0,?0,?0?},

};

int?c;

c?=?getopt_long(argc,?argv,?"D:s:d:b:lHOLC3NR",?lopts,?NULL);

if?(c?==?-1)

break;

switch?(c)?{

case?'D':

device?=?optarg;

break;

case?'s':

speed?=?atoi(optarg);

break;

case?'d':

delay?=?atoi(optarg);

break;

case?'b':

bits?=?atoi(optarg);

break;

case?'l':

mode?|=?SPI_LOOP;

break;

case?'H':

mode?|=?SPI_CPHA;

break;

case?'O':

mode?|=?SPI_CPOL;

break;

case?'L':

mode?|=?SPI_LSB_FIRST;

break;

case?'C':

mode?|=?SPI_CS_HIGH;

break;

case?'3':

mode?|=?SPI_3WIRE;

break;

case?'N':

mode?|=?SPI_NO_CS;

break;

case?'R':

mode?|=?SPI_READY;

break;

default:

print_usage(argv[0]);

break;

}

}

}

int?main(int?argc,?char?*argv[])

{

int?ret?=?0;

int?fd;

parse_opts(argc,?argv);

fd?=?open(device,?O_RDWR);

if?(fd?

pabort("can't?open?device");

/*

*?spi?mode

*/

ret?=?ioctl(fd,?SPI_IOC_WR_MODE,?&mode);

if?(ret?==?-1)

pabort("can't?set?spi?mode");

ret?=?ioctl(fd,?SPI_IOC_RD_MODE,?&mode);

if?(ret?==?-1)

pabort("can't?get?spi?mode");

/*

*?bits?per?word

*/

ret?=?ioctl(fd,?SPI_IOC_WR_BITS_PER_WORD,?&bits);

if?(ret?==?-1)

pabort("can't?set?bits?per?word");

ret?=?ioctl(fd,?SPI_IOC_RD_BITS_PER_WORD,?&bits);

if?(ret?==?-1)

pabort("can't?get?bits?per?word");

/*

*?max?speed?hz

*/

ret?=?ioctl(fd,?SPI_IOC_WR_MAX_SPEED_HZ,?&speed);

if?(ret?==?-1)

pabort("can't?set?max?speed?hz");

ret?=?ioctl(fd,?SPI_IOC_RD_MAX_SPEED_HZ,?&speed);

if?(ret?==?-1)

pabort("can't?get?max?speed?hz");

printf("spi?mode:?%d\n",?mode);

printf("bits?per?word:?%d\n",?bits);

printf("max?speed:?%d?Hz?(%d?KHz)\n",?speed,?speed/1000);

transfer(fd);

close(fd);

return?ret;

}

————————————————

先用gcc編譯

原文鏈接：https://blog.csdn.net/qq_36373500/article/details/72962887

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