Updated: 2022/Sep/29

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SCMD(4)                      Device Drivers Manual                     SCMD(4)

NAME
     scmd - Common driver for the Sparkfun Serial Controlled Motor Driver

SYNOPSIS
     scmd* at iic? ...
     scmd* at spi? ...

DESCRIPTION
     The scmd driver provides the common framework to the Sparkfun SCMD board.
     The SCMD board is a Cypress core ARM SOC in front of a DRV8835 motor
     driver chip.  There are a number of ways to talk to the board and
     scmdi2c(4) and scmdspi(4) should be consulted for the I2C and SPI
     frontend drivers.  The board is fully documented in the datasheet for at
     Sparkfun.

     The board provides a register address space of 126 registers which
     control the various behaviors of the motors attached to the board.  Each
     SCMD board can handle two motors, and up to 16 SCMD boards may be chained
     together allowing for 34 motors to be controlled from a single master
     instance.  The secondary boards are accessed by set of view port
     registers from the main board.  The scmd(4) driver and its associated
     frontends flatten the main SCMD board and all chained boards into a
     linear register space that can be opened, seeked, read from and written
     to like any other file or device without having to worry about the view
     port.

     A command line utility scmdctl(1) is provided that allows convient
     command line commands for most of the functions provided by the SCMD
     board.

SYSCTL VARIABLES
     The following sysctl(3) variables are provided:

     hw.scmd0.debug
             If the driver is compiled with SCMD_DEBUG, this node will appear
             and can be used to set the debugging level.

FILES
     /dev/scmdu     character device allowing access to the register space of
                    a main u, SCMD device

SEE ALSO
     iic(4), spi(4), scmdi2c(4), scmdspi(4), scmdctl(1), sysctl(8)

HISTORY
     The scmd driver first appeared in NetBSD 10.0.

AUTHORS
     The scmd driver was written by Brad Spencer <brad@anduin.eldar.org>.

NetBSD 9.99                     January 1, 2022                    NetBSD 9.99