SAA7385 Datasheet, PDF (19/64 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
COMMAND
DESCRIPTION
COPY_RESULTS
Copies current ECC RAM contents to the buffer memory:
CORRECT_P_SYNDROMES
CORRECT_Q_SYNDROMES
TEST_ECC_ROM
TEST_ECC_RAM_READ
TEST_ECC_RAM_WRITE
1. Copy header flags from ECC RAM to buffer (Mode 2, Form 1 only)
2. Copy error Flags from ECC RAM to buffer
3. Copy CRC remainder from ECC RAM to buffer
4. Copy P syndromes from ECC RAM to buffer
5. Copy Q syndromes from ECC RAM to buffer.
Scan all P syndromes and perform P-syndrome calculation. The microcontroller
status bits PS_EQ0, QS_EQ0 and FLAGS_EQ0 are updated at the end of this
operation.
Scan all Q syndromes and perform Q-syndrome calculation. The microcontroller
status bits PS_EQ0, QS_EQ0 and FLAGS_EQ0 are updated at the end of this
operation.
Read each exponent and log in the alpha ROM to the NUM_COR register.
This command may only be terminated by the ASSERT_ABORT command.
Read ECC RAM addresses 0 : 591 and copy to buffer addresses 0 : 591.
Read buffer addresses 0 : 591 and copy to ECC RAM addresses 0 : 591.
Note
1. 16 : 2075 and 0 : 2067 are address frame offsets. The frame buffer organization is shown in Table 75.
8.3 Microcontroller interrupts
An interrupt pulse is generated upon completion of any of the following commands:
• CALCULATE_SYNDROMES (not Mode 2, Form 1)
• CALCULATE_SYNDROMES (Mode 2, Form 1)
• CRC_RECALCULATE (not Mode 2, Form 1)
• CRC_RECALCULATE (Mode 2, Form 1)
• COPY_RESULTS (not Mode 2, Form 1)
• COPY_RESULTS (Mode 2, Form 1)
• CORRECT_P_SYNDROMES
• CORRECT_Q_SYNDROMES
• TEST_ECC_ROM
• TEST_ECC_RAM_READ
• TEST_ECC_RAM_WRITE.
If a command is aborted by the ASSERT_ABORT command, a spurious interrupt may be generated within five clock
cycles of the ASSERT_ABORT command.
1996 Jun 19
19