i2cset - set I2C registers

小鱼儿 2022-11-15 15:53 21阅读 0赞

[bionic][] ([8][]) [i2cset.8.gz][]

Provided by: [i2c-tools\_4.0-2\_amd64][i2c-tools_4.0-2_amd64] [![bug][]][bug 1]

**SYNOPSIS**

i2cset [-f] [-y] [-m mask] [-r] i2cbus chip-address data-address [value] ...  [mode]
           i2cset -V

**DESCRIPTION**

i2cset is a small helper program to set registers visible through the I2C bus.

**OPTIONS**

-V     Display the version and exit.
    
           -f     Force  access  to  the  device  even if it is already busy. By default, i2cset will
                  refuse to access a device which is already under the control of  a  kernel  driver.
                  Using  this  flag  is  dangerous,  it  can  seriously  confuse the kernel driver in
                  question. It can also cause i2cset to silently write to the wrong register. So  use
                  at your own risk and only if you know what you're doing.
    
           -y     Disable  interactive mode. By default, i2cset will wait for a confirmation from the
                  user before messing with the I2C bus. When this flag is used, it will  perform  the
                  operation directly. This is mainly meant to be used in scripts.
    
           -m mask
                  The  mask  parameter,  if specified, describes which bits of value will be actually
                  written to data-address. Bits set to 1 in the mask are taken from value, while bits
                  set to 0 will be read from data-address and thus preserved by the operation. Please
                  note that this parameter assumes  that  the  read  and  write  operations  for  the
                  specified  mode  are  symmetrical for the device you are accessing. This may or may
                  not be the case, as neither I2C nor SMBus guarantees this.
    
           -r     Read back the value right after writing it, and compare the result with  the  value
                  written.  This used to be the default behavior. The same limitations apply as those
                  of option -m.
    
           There are three required options to i2cset. i2cbus indicates the number or name of the I2C
           bus to be scanned.  This number should correspond to one of the busses listed by i2cdetect
           -l. chip-address specifies the address of the chip on that bus, and is an integer  between
           0x03  and  0x77.   data-address  specifies the address on that chip to write to, and is an
           integer between 0x00 and 0xFF.
    
           The value parameter, if specified, is the value to write to that location on the chip.  If
           this parameter is omitted, then a short write is issued. For most chips, it simply sets an
           internal pointer to the target location, but doesn't actually write to that location.  For
           a  few chips though, in particular simple ones with a single register, this short write is
           an actual write. If the mode parameter is s or i, multiple values can be specified.
    
           The mode parameter, if specified, is one of the letters b, w, s, or i, corresponding to  a
           write  size  of  a single byte, a 16-bit word, a SMBus block write, or an I2C block write,
           respectively.  For SMBus and I2C block writes, the write size is determined by the  number
           of  value  parameters.   Except for I2C block writes, a p can also be appended to the mode
           parameter to enable PEC.  If the mode parameter is omitted, i2cset defaults to  byte  mode
           without  PEC.  The  value  provided  must  be  within  range  for  the specified data type
           (0x00-0xFF for byte and block writes, 0x0000-0xFFFF for words).  Another possible mode  is
           c,  which  doesn't  write  any  value  (so-called  short write). You usually don't have to
           specify this mode, as it is the default when no value is provided, unless you also want to
           enable PEC.

**WARNING**

i2cset  can  be extremely dangerous if used improperly. It can confuse your I2C bus, cause
           data loss, or have more serious side effects. Writing to a serial EEPROM on a memory  DIMM
           (chip  addresses  between  0x50  and  0x57)  may  DESTROY your memory, leaving your system
           unbootable!  Be extremely careful using this program.

**EXAMPLES**

Write value 0x42 to 8-bit register 0x11 of the I2C device at 7-bit address 0x2d on  bus  1
           (i2c-1), after user confirmation:
                  # i2cset 1 0x2d 0x11 0x42
    
           Immediately clear the 3 least significant bits of 8-bit register 0x11 of the I2C device at
           7-bit address 0x2d on bus 1 (i2c-1) (no user confirmation):
                  # i2cset -y -m 0x07 1 0x2d 0x11 0x00
    
           Write value 0x5000 to 16-bit register 0x02 of the I2C device at 7-bit address 0x48 on  bus
           1 (i2c-1), after user confirmation:
                  # i2cset 1 0x48 0x02 0x5000 w
    
           Also see i2cget(8) for examples of combined usage of i2cset and i2cget.

**SEE** **ALSO**

i2cdetect(8), i2cdump(8), i2cget(8), i2ctransfer(8), isaset(8)

**AUTHOR**

Frodo Looijaard, Mark D. Studebaker and Jean Delvare
    
           This  manual page was originally written by David Z Maze <dmaze@debian.org> for the Debian
           GNU/Linux system.
    
                                               October 2017                                 I2CSET(8)

///

# [How to write to a 16-bit I2C address using i2cset][] #

Trying to write a byte to a 16-bit address on an I2C device (OV5640 camera) using i2cset. I can successfully read from the device registers using the following sequence (read byte from device address 0x3c and register address 0x3030): 'i2cset -v -f 1 0x3c 0x30 0x30' 'i2cget -v -f 1 0x3c'

To write to the device, I use this sequence (write byte 0x40 to device address 0x3c and register address 0x3030): 'i2cset -v -f 1 0x3c 0x30 0x30' 'i2cset -v -f 1 0x3c 0x40' This sequence does not show any errors but when the address is read again, the value is unchanged. Can anyone provide any insight on the correct i2cset syntax to use when writing to this device? Thanks for you input.

读寄存器地址:(register address 0x3030），iic总线1，设备地址0x3c：

i2cset -v -f 1 0x3c 0x30 0x30

i2cget -v -f 1 0x3c

尝试写寄存器地址(register address 0x3030），iic总线1，设备地址0x3c，写入值：0x40：

i2cset -v -f 1 0x3c 0x30 0x30     注：即是先写地址，在写值    无法写入

i2cset -v -f 1 0x3c 0x40

*  Your title seems a bit off. I2C addresses are either 7-bit or 10-bit. You seem to mean address of register inside this I2C device? Are you sure your write sequence is correct. Without looking at the datasheet (which you should paste the relevant info from), it seems to be it should be something like `i2cset -v -f 1 0x3c 0x30 0x30 0x40` (one write, instead of two writes). – [domen][] [Oct 9 '20 at 9:04][Oct 9 _20 at 9_04]

## 1 Answer ##

SOLVED! I found the solution for this and it requires using the i2cset block write option (i) as follows: i2cset -y -f 2 0x3c 0x30 0x30 0x40 i

This command writes the value 0x40 to register address 0x3030 at device address 0x3c.

成功的方法：

尝试写寄存器地址(register address 0x3030），iic总线1，设备地址0x3c，写入值：0x40：

i2cset -y -f 2 0x3c 0x30 0x30 0x40 i

[bionic]: http://manpages.ubuntu.com/manpages/bionic/
[8]: http://manpages.ubuntu.com/manpages/bionic/man8
[i2cset.8.gz]: http://manpages.ubuntu.com/manpages.gz/bionic/man8/i2cset.8.gz
[i2c-tools_4.0-2_amd64]: https://launchpad.net/ubuntu/bionic/+package/i2c-tools
[bug]: /images/20221022/2dd35f838305458397eaf01fa42dbab8.png
[bug 1]: https://bugs.launchpad.net/ubuntu/+source/i2c-tools/+filebug-advanced
[How to write to a 16-bit I2C address using i2cset]: https://stackoverflow.com/questions/64270160/how-to-write-to-a-16-bit-i2c-address-using-i2cset
[domen]: https://stackoverflow.com/users/421550/domen
[Oct 9 _20 at 9_04]: https://stackoverflow.com/questions/64270160/how-to-write-to-a-16-bit-i2c-address-using-i2cset#comment113661829_64270160