Getting Started
43
2.6.7
Accessing User LEDs
You can access the user LEDs through a register on the SMBus.
The standard Linux I2C tools give access to SMB registers.
Use the 7-bit SMB/I2C address to access a register.
»
Find out the number of the SMBus where the user LED register is located on
MC50M.
»
If you are unfamiliar with the standard Linux tools, please read the related applica-
tion note.
The following examples assume that the SMBus number is 1.
»
Enable the LEDs:
»
Turn the LEDs on:
»
Read out the LED state:
»
Set both LEDs back to their default dimmed state:
Chapter CPU Module User LED and Ignition Watchdog
for the register description.
See
Chapter Accessing SMBus/I2C Devices using Standard Linux I2C Tools
.
Access the Configuration Register on 0x03.
$
i2cset -y 1 0x20 0x03 0xcf b
Access the Data Register on 0x01.
$
i2cset -y 1 0x20 0x01 0xcf b
Access the Data Register on 0x00.
$
i2cget -y 1 0x20 0x00
$
i2cset -y 1 0x20 0x03 0xff b