Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
spi(8)			  BSD System Manager's Manual			spi(8)

NAME
     spi -- communicate	on SPI bus with	slave devices

SYNOPSIS
     spi [-f device] [-d r|w|rw] [-m mode] [-s max-speed] [-c count]
	 [-C cmd_bytes]	[-A] [-b] [-L] [-v]
     spi [-i] [-f device] [-v]
     spi [-h]

DESCRIPTION
     The spi utility can be used to perform raw	data transfers (read, write,
     or	simultaneous read/write) with devices on the SPI bus, via the
     spigen(4) device.

     Each spigen(4) device is associated with a	specific `chip select' (cs)
     pin on the	spibus,	and therefore needs to be specified.  If no device
     name is specified on the command line, spi	assumes	`spigen0.0'.

     For more information on the spigen	device,	see spigen(4).

     The options are as	follows:

     -A		Specifies ASCII	mode.  Both read and write data	is input and
		output as 2-character hexadecimal values, optionally separated
		by white space,	such as	00 01 02 etc.  When combined with the
		`-b' flag, the data on stdin remains a sequence	of ASCII hexa-
		decimal	byte values, but the output reverts to binary mode.

     -b		Binary (output)	mode.  Only has	an effect when `-A' has	been
		specified.  Reverts the	output back to binary (rather than
		ASCII),	while leaving the input	format as-is.  Use in combina-
		tion with `-A' to allow	using something	like `echo' to pass
		hexadecimal values to the SPI device, but output the received
		data on	stdout as binary.

     -C	command	bytes
		Sends one or more `command' bytes, skipping any	bytes read-in
		during the transfer.  The byte values should be	specified as a
		quoted parameter, similar to the format	for data on stdin for
		`-A', that is, 2 character hexadecimal values, optionally sep-
		arated by white	space.	An SPI device will typically require
		that a command be sent,	followed by bytes of data.  You	can
		use this option	to send	the command without receiving any data
		bytes during the command sequence.

     -c	count	The total number of bytes to transfer as a decimal integer.
		If a write or a	read/write transaction is being	performed, and
		fewer than this	number of bytes	are read in from stdin,	the
		remaining bytes	will be	sent with a value of `0'.  If the
		length can be determined from the input	file size, you can use
		a `count' value	of `-1'	to base	the transfer on	the input
		file's size.

     -d	r|w|rw	Transfer direction: Use	`r' for	read, `w for write, and' `rw'
		for simultaneous read and write.

     -f	device	SPI device to use (default is /dev/spigen0).

     -h		Print help text	to stderr, explaining the command line op-
		tions.

     -i		Displays information about the SPI device to stderr.  Whenever
		this flag is specified,	no data	is read	or written, and	the
		mode and clock speed are not changed.

     -L		LSB bit	order.	The default is MSB, i.e., the highest order
		bit is transmitted first.  Specifying -L caused	the LSB	to be
		transmitted and	read first.

     -m	0 - 3	SPI mode, 0 through 3.	This defines the clock phase and tim-
		ing with respect to reading and	writing	data, as per the SPI
		specification.

     -s	speed	Specify	the maximum speed, in Hz, for the SPI clock.  The bus
		will operate at	its highest available speed which does not ex-
		ceed this maximum.

     -v		Specifies Verbose mode.	 Diagnostics and information are writ-
		ten to stderr.	You can	specify	`-v' more than once to in-
		crease verbosity.

EXAMPLES
     Here are a	few examples of	using the spi utility:

     +o	 Get information about the default SPI device

	 spi -i

     +o	 Set the maximum clock speed to	200Khz and the mode to 3 on spigen0.1,
	 but do	not transmit nor receive any data

	 spi -f	spigen0.1 -s 200000 -m 3

     +o	 Send a	command	sequence consisting of 2 bytes,	and read 2 additional
	 bytes from the	SPI device, using the current mode and speed on	the
	 default device

	 spi -d	r -C "00 01" -c	2

     +o	 Transmit a byte value of 5, and receive 2 bytes, displaying their
	 values	as 2-byte ASCII	hexadecimal, with mode 2, and a	maximum	clock
	 speed of 500khz.

	 echo "05" | spi -A -d rw -m 2 -s 500000 -c 2

     +o	 Send a	binary file, and output	the SPI	result through `od' as hexa-
	 decimal bytes,	using the current maximum clock	speed and SPI mode.

	 spi -d	rw -c -1 <input_file.bin | od -An -t x1

     +o	 Send 2	bytes of data, receive a total of 4 bytes, and output the SPI
	 result	as binary data,	piped through `od', displaying it as two hexa-
	 decimal unsigned short	integer	values.

	 echo "00 01" |	spi -A -b -d rw	-c 4 | od -t x2

     +o	 Query the manufacturer	ID and size from a standard spiflash device,
	 by sending the	command	byte 0x9f and displaying the 3-byte reply in
	 ASCII hex.

	 spi -f	spigen0.0 -m 0 -s 1000000 -d r -c 3 -A -C 9f

SEE ALSO
     spigen(4)

BSD			       December	8, 2019				   BSD

NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | SEE ALSO

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=spi&sektion=8&manpath=FreeBSD+12.1-RELEASE+and+Ports>

home | help