Kurobox Pro Microcomputer Communication Specifications

=Contents=

=Functions=

Overview of Functions
Communicates with the main CPU via UART. The main functions are shown below.


 * Power SW monitoring
 * Initialization SW monitoring
 * Power control
 * Temperature measurement
 * Buzzer control
 * Watchdog function (However, watchdog function is disabled on u-boot)
 * LAN ACT monitoring
 * LED display
 * Reset sequence generation
 * LED Illumination

=UART Communication with Main CPU=

UART Basic Settings

 * Transmission speed: 38400bps
 * Data bit: 8bit
 * Parity: Even
 * Stop bit: 1 bit or more

Communication with Main CPU

 * Basic communication is performed by the transmission of commands, data, and parity.
 * When switches etc are pressed, a level interrupt occurs. The interrupt is cleared when reporting to the CPU is completed.
 * If many frame errors occur, regulate the guard time on the main CPU.

Preamble
The receive buffer is completely cleared by sending FF 35 times.

Write Command
LED Lighting control etc Command Micro- computer CPU DATA0 DATA1 DATAn(MAX31) PARITY Switch to data transfer phase Switch to command phase Command (OPCODE) ACK Command Command 2nd byte PARITY

Read Command
Temperature read by CPU DATA0 DATA1 DATAn(MAX31) PARITY Command (OPCODE) PARITY Command CPU Micro- computer Switch to data transfer phase Switch to command phase

Interrupt + Read Command
SW Micro- computer DATA0 DATA1 DATAn(MAX31) PARITY Interrupt assert Interrupt negate Switch to data transfer phase Switch to command phase Command (OPCODE) PARITY Command CPU

Command Construction
The command is a 2 byte command.

Read (Microcomputer -> CPU)
Command List

Data 0
Frequency settings lower order

Data 1
Frequency settings upper order

Data
Set the time until the power goes OFF for forced OFF. You can set up to 255 seconds.

However, setting to 0 will cause the system watchdog to stop and not operate.

If read is performed, the time for the watchdog to operate is displayed.

0×FF – (time to shutdown) = Setting value

Data
The temperature on the board can be read.

The read data is signed char.

The data is from -55°C to 125°C.

Data
If SW or INITSW is pressed, an interrupt occurs. You can research the cause of an

interrupt by reading the SW.

Reading this resistor clears the interrupt. 

measure the pressed time on the CPU to judge.
 * If the SW is released at the point when read is started, the value returns to 1. Therefore,

Second operand

 * Switching LED control rights: 0×50
 * Switching LED on/off: 0×51
 * Flash LED: 0×52

Control Rights Switching

 * 0: LED control performed by microcomputer
 * 1: LED control performed by CPU

Switching on/off

 * 0: Switch LED off
 * 1: Light LED

Flash Switching

 * 0: Do not flash LED
 * 1: Flash LED

LED Illumination
Setting possible in the 0-0xf range
 * 0×0 = Off
 * 0×f = Maximum illumination

Data
=ACK/NACK List=

=References=
 * Kurobox Pro microprocessor interface specifications