Setup

1. Main functions of VCD I / F board

VCD I / F board (RT-V1A) is a command and message communication between the PC compatible machine and the CD block (RT-V1B) in the target box. -ISA expansion board for PC compatible machines that sends out ROM data, CD-DA data, etc.

(1) Communication with CD block

Receives a command from the CD block, performs the specified processing according to the contents, and returns the status to the CD block.

(2) Communication with PC compatible machine body
Of the commands from the
CD block, the necessary commands are extracted and sent to the PC compatible machine. In contrast, the PC compatible main unit returns data as needed.

(3) Receive data from PC compatible machine
When a PLAY command is sent to a
PC compatible machine, the PC compatible machine prepares CD-ROM data, CD-DA data, or R to W subcode data as required, but the VCDI / F board Receives these data by the DMA controller on the board.

(4) Send data to CD block
It scrambles the data imported with
(3), converts it into a serial data format, and sends it.

2. Data transfer speed

Only when transferring CD-ROM data, two transfer speeds, standard speed and double speed, are set according to the command sent from the CD block.