SAA7385GP Philips Semiconductors, SAA7385GP Datasheet - Page 51

• Manufacturer Part Number: SAA7385GP
• Description: Error correction and host interface IC for CD-ROM SEQUOIA
• Manufacturer: Philips Semiconductors

Philips Semiconductors
15.5
The S2B serial interface consists of four lines (see Fig.17):
These are used for communication. TXD and CPR for
sending acknowledges and information data to the data
path and RXD and SPR for receiving commands and
parameters from the data path. The data is transferred
frame-wise and asynchronously.
1996 Jun 19
Transmit data (TXD)
Receive data (RXD)
Data path ready to accept data; active LOW (CPR)
Basic engine ready to accept data; active LOW (SPR).
Error correction and host interface IC for
CD-ROM (SEQUOIA)
S2B interface timing
handbook, halfpage
handbook, halfpage
CPR
TXD
data path
sequoia
S0
Fig.17 S2B interface.
RXD
CPR
TXD
SPR
0
Fig.18 S2B Timing.
1
2
51
3
A data frame is proceeded by a start-bit (active LOW),
followed by the actual data byte, and again followed by a
parity bit (even parity), and a stop bit (active HIGH),
see Fig.18. In total, eleven bits per frame are incorporated.
The interface is full duplex, meaning data frames may be
transmitted and received simultaneously.
The bit-rate is selectable:
4
187.5 kbits/s with a 2.6% error
62.5 kbits/s with a 0.4% error
31.25 kbits/s with a 0.4% error.
5
TXD
CPR
RXD
SPR
basic engine
6
7
MGE403
P S1
MGE404
Preliminary specification
SAA7385