SAA7385 Datasheet, PDF (29/64 Pages) NXP Semiconductors – Error correction and host interface IC for CD-ROM SEQUOIA

Philips Semiconductors
Error correction and host interface IC for
CD-ROM (SEQUOIA)
Preliminary specification
SAA7385
9.2 Miscellaneous control registers
Table 34 53CF90 direction and audio mode control: 0xF0C1; note 1
MNEMONIC R/W
7
6
AUSWP R/W TEST
−
DATA BYTE
5
4
3
2
1
0
−
−
OVER4X BSB
−
−
Note
1. Register 0xF0C1 controls the audio mode byte swapping and a test mode bit.
Table 35 WTDIR field descriptions
FIELD
BSB
OVER4X
TEST
DESCRIPTION
Byte swap bit. Defaults to swapping the most significant byte and least significant byte in the audio
mode such that the least significant byte of all audio samples is stored at even addresses in the
DRAM. Setting this HIGH causes the audio data to be stored in the same way as in the data mode.
4× over-sampling bit selection; default LOW select transmit, or no over-sampling, mode for the
sub-code and C-flag UARTs. Setting this bit HIGH will cause the sub-code and C-flag data to be
sampled at one quarter the data rate allowing Q-channel information to be correctly stored in the
registers while the CD-60 is outputting audio data at 4× over-sampling.
Enables internal signals to be multiplexed out when the TEST pin (pin 125) is HIGH.
Table 36 SCSI mode control register: 0xF0FD; note 1
DATA BYTE
MNEMONIC R/W
7
6
5
4
3
2
1
0
SCSIMOD R/W
−
−
− OFF_ADR OFF_END OFF_STR RD_BUF BYT/PAG
Note
1. Register 0xF0FD controls the operation of the interface to the SCSI controller. The outputs of these registers are
used to directly control DRAM access cycles, and will affect any current DRAM cycle in progress.
Table 37 SCSIMOD field description
FIELD
BYT/PAG
RD_BUF
OFF_STR
OFF_END
OFF_ADR
LOGIC
DESCRIPTION
0 SCSI DRAM byte mode access
1 SCSI DRAM page mode access
0 SCSI read/write control; read from buffer memory
1 SCSI read/write control; write to buffer memory
0 SCSI offset start A/B control; select A registers
1 SCSI offset start A/B control; select B registers
0 SCSI offset end A/B control; select A registers
1 SCSI offset end A/B control; select B registers
0 SCSI transfers use only A registers
1 SCSI transfers use A and B registers
1996 Jun 19
29