xref: /freebsd/usr.sbin/spi/spi.8 (revision b9f654b163bce26de79705e77b872427c9f2afa1)
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24.\" $FreeBSD$
25.\"
26.Dd "15 April 2018"
27.Dt spi 8
28.Os
29.Sh NAME
30.Nm spi
31.Nd communicate on SPI bus with slave devices
32.Sh SYNOPSIS
33.Nm
34.Op Fl f Ar device
35.Op Fl d Ar r|w|rw
36.Op Fl m Ar mode
37.Op Fl s Ar max-speed
38.Op Fl c Ar count
39.Op Fl C Ar cmd_bytes
40.Op Fl A
41.Op Fl b
42.Op Fl L
43.Op Fl v
44.Nm
45.Op Fl i
46.Op Fl f Ar device
47.Op Fl v
48.Nm
49.Op Fl h
50.Sh DESCRIPTION
51The
52.Nm
53utility can be used to perform raw data transfers
54.Pq read, write, or simultaneous read/write
55with devices on the SPI bus, via the
56.Xr spigen 4
57device.
58.Pp
59Each
60.Xr spigen 4
61device is associated with a specific
62.Sq chip select
63.Pq cs
64pin on the spibus, and therefore needs to be specified.
65If no device name is specified on the command line,
66.Nm
67assumes
68.Sq spigen0.0 .
69.Pp
70For more information on the spigen device, see
71.Xr spigen 4 .
72.Pp
73The options are as follows:
74.Bl -tag -width ".Fl f Ar device"
75.It Fl A
76Specifies ASCII mode.
77Both read and write data is input and output as
782-character hexadecimal values, optionally separated by white space,
79such as 00 01 02 etc.
80When combined with the
81.Sq -b
82flag, the data on stdin remains a sequence of ASCII hexadecimal
83byte values, but the output reverts to binary mode.
84.It Fl b
85Binary
86.Pq output
87mode.
88Only has an effect when
89.Sq -A
90has been specified.
91Reverts the output back to binary
92.Pq rather than ASCII ,
93while leaving the input format as-is.
94Use in combination with
95.Sq -A
96to allow using something like
97.Sq echo
98to pass hexadecimal values to the SPI device, but output the received data
99on stdout as binary.
100.It Fl C Ar command bytes
101Sends one or more
102.Sq command
103bytes, skipping any bytes read-in during the transfer.
104The byte values should be specified as a quoted parameter, similar to the
105format for data on stdin for
106.Sq -A ,
107that is, 2 character hexadecimal values, optionally separated by white space.
108An SPI device will typically require that a command be sent, followed by
109bytes of data.
110You can use this option to send the command without receiving any data bytes
111during the command sequence.
112.It Fl c Ar count
113The total number of bytes to transfer as a decimal integer.
114If a write or a read/write transaction is being performed, and fewer than
115this number of bytes are read in from stdin, the remaining bytes will be
116sent with a value of
117.Sq 0 .
118If the length can be determined from the input file size, you can use a
119.Sq count
120value of
121.Sq -1
122to base the transfer on the input file's size.
123.It Fl d Ar r|w|rw
124Transfer direction: Use
125.Sq r
126for read,
127.Sq w for write, and
128.Sq rw
129for simultaneous read and write.
130.It Fl f Ar device
131SPI device to use
132.Pq default is /dev/spigen0 .
133.It Fl h
134Print help text to stderr, explaining the command line options.
135.It Fl i
136Displays information about the SPI device to stderr.
137Whenever this flag is specified, no data is read or written, and the mode
138and clock speed are not changed.
139.It Fl L
140LSB bit order.
141The default is MSB, i.e., the highest order bit is
142transmitted first.
143Specifying -L caused the LSB to be transmitted and read first.
144.It Fl m Ar 0 - 3
145SPI mode, 0 through 3.
146This defines the clock phase and timing with respect to reading and writing
147data, as per the SPI specification.
148.It Fl s Ar speed
149Specify the maximum speed, in Hz, for the SPI clock.
150The bus will operate at its highest available speed which does not
151exceed this maximum.
152.It Fl v
153Specifies Verbose mode.
154Diagnostics and information are written to stderr.
155You can specify
156.Sq -v
157more than once to increase verbosity.
158.El
159.Sh EXAMPLES
160Here are a few examples of using the spi utility:
161.Bl -bullet
162.It
163Get information about the default SPI device
164.Pp
165spi -i
166.It
167Set the maximum clock speed to 200Khz and the mode to 3 on spigen0.1, but do
168not transmit nor receive any data
169.Pp
170spi -f spigen0.1 -s 200000 -m 3
171.It
172Send a command sequence consisting of 2 bytes, and read 2 additional bytes
173from the SPI device, using the current mode and speed on the default device
174.Pp
175spi -d r -C "00 01" -c 2
176.It
177Transmit a byte value of 5, and receive 2 bytes, displaying their values as
1782-byte ASCII hexadecimal, with mode 2, and a maximum clock speed of 500khz.
179.Pp
180echo "05" | spi -A -d rw -m 2 -s 500000 -c 2
181.It
182Send a binary file, and output the SPI result through
183.Sq od
184as hexadecimal bytes, using the current maximum clock speed and SPI mode.
185.Pp
186spi -d rw -c -1 <input_file.bin | od -An -t x1
187.It
188Send 2 bytes of data, receive a total of 4 bytes, and output the SPI result
189as binary data, piped through
190.Sq od ,
191displaying it as two hexadecimal unsigned short integer values.
192.Pp
193echo "00 01" | spi -A -b -d rw -c 4 | od -t x2
194.It
195Query the manufacturer ID and size from a standard spiflash device, by
196sending the command byte 0x9f and displaying the 3-byte reply in ASCII hex.
197.Pp
198spi -f spigen0.0 -m 0 -s 1000000 -d r -c 3 -A -C 9f
199
200.El
201.Pp
202.Sh SEE ALSO
203.Xr spigen 4
204