83Plus:Ports:0A

Synopsis

Port Number: 0Ah

Function: Link Assist Input Buffer/CPU Speed 1 Signaling Rate

This port allows you to read the data that has been received by the link assist.

Read Values

• [00h - FFh]: Byte currently in the link assist's buffer.

Write Values

Writing controls the signaling rate of the link assist in CPU speed mode 1. See port 09 for details.

Comments

This port only exists on the 83+ SE and the 84+.

Check port 9 before you read this port, to see that there is valid data. Also, do not read this port more than once per data byte received.

Example

GetByteSE:
	in a,(4)
	and 8
	jr z,LinkError
	in a,(9)
	bit 6,a
	jr nz,LinkError
	and 11h
	jr z,GetByteSE
	in a,(0Ah)
	ret

Credits and Contributions

• Michael Vincent: Original documentation of the link assist