scmd(4) - NetBSD Manual Pages

SCMD(4)                 NetBSD Kernel Interfaces 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 fron-
     tend drivers.  The board is fully documented in the datasheet for at
     Sparkfun.

     The board provides a register address space of 126 registers which con-
     trol 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 regis-
     ters from the main board.  The scmd(4) driver and its associated fron-
     tends 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 com-
     mand 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 10.99                    January 1, 2022                   NetBSD 10.99