SAA7385 Datasheet, PDF (21/64 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
Table 10 INTRFLG field descriptions
FIELD
FRM_STR
STR_LST
FE_2352
FE_HDR
ECC_COR
RFERXINT
FETXINT
DESCRIPTION
set one when one complete frame is stored
set at the start of the last frame
set if the front-end data exceeds 2352 bytes
front-end interrupt for header (or Q channel) ready
ECC interrupt for correction complete
front-end interrupt for receive ready
front-end interrupt for transmit ready
8.4 Microcontroller RAM organization
MICFRM# is used to determine the frame address for the microcontroller access through the frame window 0x8000 to
0x8FFF. To obtain the actual byte location within the buffer RAM, the lower 12 bits of the microcontroller address form
the relative offset and hence the absolute address is found.
Note that the microcontroller has the option of addressing memory in a linear fashion using the 32 kbyte address space
between 0x000 and 0x7FFF. If this 32 kbyte page is used, the PAGEREG must be programmed with the required page
address. PAGEREG is used to select the required page when the microcontroller makes a linear access to the buffer
memory using the address space 0x7000 to 0x7FFF. The actual address is the fifteen LSBs from the microcontroller plus
32768 times the value in PAGEREG.
Table 11 Microcontroller frame number address registers: 0xF0F6 and 0xF0F7
MNEMONIC R/W
MICFRM# R/W
MICFRM# R/W
7
NUM7
−
6
NUM6
−
5
NUM5
−
DATA BYTE
4
NUM4
−
3
NUM3
−
2
NUM2
−
1
NUM1
−
0
NUM0
NUM8
Registers 0xF0F6 and 0xF0F7 provide the frame number address for the microcontroller access to memory. The counter
associated with these registers is loaded after the most significant byte is written; the least significant byte must be written
first to ensure that the counter is loaded correctly. If a DRAM access is in progress that uses the address from the
counter, the update will be delayed until the access is complete.
1996 Jun 19
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