SAA7385GP Philips Semiconductors, SAA7385GP Datasheet - Page 22

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

Philips Semiconductors
Table 12 Microcontroller address page register: 0xF0FF
Note
1. PAGE_EN is disconnected.
Register 0xF0FF is used by the buffer manager for the upper address lines when the microcontroller addresses
non-frame memory. These registers overlap frame memory, so register 0xF0FF must be programmed with an address
in the top part of the memory if no overlap is required. The microcontroller page address line is selected from this register.
The outputs are used directly to control DRAM access cycles, and will affect any current DRAM cycle in progress.
It is possible to access three contiguous frames from the microcontroller by reading the three data sector windows,
0x8000 to 0x8FFF, 0x9000 to 0x9FFF and 0xA000 to 0xAFFF. This function is required for the decoding of the sub-code
information. If the ‘next’ frame wraps past the last frame pointer (LASTFRM) then the pointers are modified to wrap back
to the start pointer onwards (FEFRM#); this section is transparent to the microcontroller.
Table 13 Program memory control register: 0xF09F
Register 0xF09F controls a system test feature where an SRAM is used for the 80C32 external program memory;
note DATAPRG must be set for any of these features to be enabled.
Table 14 PRGMEM field descriptions
1996 Jun 19
INV_A15
SEL_TOP
EN_WIN
DATAPRG
MNEMONIC
MNEMONIC
PAGEREG
PRGMEM
Error correction and host interface IC for
CD-ROM (SEQUOIA)
FIELD
LOGIC
R/W
R/W
R/W
R/W
0
1
0
1
0
1
0
1
DATAPRG EN_WIN SEL_TOP
normal operation
invert A(15) to program memory for data memory access
select bottom 32 kbyte window
select top 32 kbyte window
windowing disabled
32 kbyte windows are enabled and SEL_TOP is used to determine window selected
normal operation
data memory is mapped to program memory and data memory DRAM accesses are
disabled
7
7
6
6
PAGE_EN
5
5
22
(1)
INV_A15
DESCRIPTION
MA_19
DATA BYTE
DATA BYTE
4
4
MA_18
3
3
MA_17
2
2
Preliminary specification
MA_16
1
1
SAA7385
MA_15
0
0