W88113C Datasheet, PDF (94/102 Pages) Winbond – ATAPI CD-ROM DECODER & CONTROLLER

W88113C
5.4.10 Target Search
The target search logic is initialized by: (1) setting Search Limit, (2) setting Target and (3) setting
TARGEN (80h.w7) high. After the decoding is triggered through CTRL0 (0Ah,w), the first sector
ready interrupt is generated when: i) the target sector is found, ii) header is larger than target or iii)
search limit is reached. If event ii) or iii) occurs, the microprocessor may read out HEAD0-2 (04h-
06,r) to determine the current distance from target. Setting LTTIEN (80h.w2) and TNFEN (80h.w1)
high can generate the associated interrupt flag on SRIb (01h.r5) before the target is found.
decoder_ini
decoder_on
SRIb(01h.r5)
set TSL(83h)
CTRLW(10h) = 50h
yMonitor_Mode?
no
yMonitor_Mode?
no
HCEI(80h.0) or
STAERR(80h.6)
yes
set BIA(09h/08h)
yMonitor_Mode = 1
set DDB(29h/28h)
yes
no
return
Target(84h-86h) = T - 1
Tarctl(80h) = 8Fh
CTRL1(0Bh)
= F0h for mode 1
= F8h for mode 2
TNFI(80h.1) or
LTTI(80h.2)
Cache
Management
yes
stop_decoder
CTRLW(10h) = 10h
CTRL0(0Ah) = 80h
Mask(8Ch) = 80h
no
yes
yMonitor_Mode = 0
yCache_Full?
CTRL0(0Ah) = 00h
CTRL0(0Ah) = B7h
decoder_on
yes
no
decoder_stop
return
return
return
return
5.4.11 Automatic Header Comparison
The automatic header comparison logic is enabled by setting TARGEN (80h.w7) and HCEEN
(80h.w0) high. After the first target is found, the value in TARGET (84h-86h) increases from (T - 1) to
T. And the decoder is changed from disk-monitor mode to buffer-correction mode. Then HEAD0-2
(04h-06h,r) are compare with TARGET (84h-86h) and generate flag HCEI (80h.r0) at the end of EDC-
checking. Unless flag STAERR (80h.r6) or HCEI (80h.r0) is generated, the value in TARGET (84h-
86h) is automatically incremented by one and ready to be compared with next sector.
5.4.12 Status Collection
The status collection logic is enabled if any bit in the Status-Mask-Register (8Ch-8Fh,w) is set high.
At the end of EDC-checking, flag STAERR (80h.r6) becomes high if any status bit error that is
enabled by its associating mask bit occurs. The microprocessor can reduce the system overhead by
checking STAERR (80h.r6) rather than reading out STAT (0Ch-0Fh,r).
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Publication Release Date: Mar. 1999
Revision 0.61