2.0  Communication Procedure

Communication proceeds as diagrammed below:



2.1  Connection Request/Connection Reply
Before the actual data transfer begins, a connection confirmation pulse is sent back and forth to confirm that the IR communication module is operating normally.

The receiving side receives the connection part of the signal. If it recognizes the connection pulse, it returns the same pulse back to the transmitting side. After that, the transmitting side determines whether the returned signal is a normal connection pulse. If the signal is not recognized to be a normal connection pulse, then communication will terminate.



2.2  Header
The header transmits the 1-halfword (16 bit) sum total of the data class (8bit) + data transfer size (8bit).

Communication will terminate if the data class is an unregistered illegal constant or if the data transfer size exceeds the permissible byte size of the receiving side.



2.3  Data
The amount of data specified by the 8bit "data transfer size" part of the header is transmitted consecutively. The amount of data that can be transmitted consecutively is 0 ~ 255 halfwords.



2.4  Checksum
This part transmits the checksum (1 halfword) calculated by the transmitting side.



2.5  Status
The receiving side returns its communication status (1 halfword).

Table of Communication Status Values

Status Value

State

Explanation

IR_NORMAL

Normal

No error occurred

IR_PULSE_ERR

Pulse error

An abnormal pulse was received

IR_SUM_ERR

Checksum error

The checksum value sent by the transmitting side was not equal to the checksum value calculated by the receiving side.

IR_BYTES_ERR

Byte error

The transfer request data byte size exceeded the byte size permitted by the receiving side.

IR_CODE_ERR

Code error

The data class is an unregistered illegal constant.