Device Drivers

Overview

For testing some device drivers may be loaded or unloaded dynamically or a startup script may be used to automatically load the modules.

Driver	Module Filename	Device Nodes	Depends on other modules
Mainboard communications	mnbd-comm.ko	/dev/mnbd /dev/wt1 .. /dev/wt10
USB Hub	isp1520.ko	i2c-mcf, i2c-core
Keypad/Beeper	max734x.ko	/dev/cardbeep	I2c-mcf, i2c-core

Device driver operation may be tested from command line for some functions, for example:

# echo “A,B,C” > /dev/cardbeep <CR>

Play notes A, B, and C on beeper. (refer to beeper section for more details)

# echo “W” > /dev/wt1 <CR>

Request weight from scale one.

# cat < /dev/wt1 <CR>

Display response to previous request from scale 1 as a weight structure converted to hexadecimal.

01004812B682000000004812B6820003

struct mnbd_wt_struct
{
  unsigned char interval;          (01 – interval 1)
  unsigned char decimal;           (00 – no decimal)
  float grosswt;                   (4812B682 – IEEE floating point value)
  float tarewt;                    (00000000 – IEEE floating point value–tare zero)
  float netwt;                     (4812B682 – IEEE floating point value)
  unsigned char units;             (00 – units)
  unsigned char status;            (03 – status)
};