
Preliminary/Confidential
Subject to change without notice
W88227F/W88227QD
- 90 -
1999/10/1 Rev: 0.70
Bit 5:
BLIMEN - Buffer Limit Enable
If
BLIMEN (9Ah.5)
is high, the buffering of DSP data stops when the condition defined by
BLIMS
(9Ah.4)
is met. This function should be enabled if
BICEN (9Ah.7)
is set high.
BLIMS - Buffer Limit Source Select
Bit 4:
If
BLIMS (9Ah.4)
is high, the buffering stop when
BUFC (9Bh,r)
reach
BUFLIM (9Bh,w)
. If
BLIMS
(9Ah.4)
is low, the buffering stops when
buffering block (internal) reach
TBH/L (24h/25h,r)
minus 1.
Bit 3-0: RCLIM[3:0] - Repeat Correction Limit
If
BICEN (9Ah.7)
is high, these four bits specify the maximum number of repeat correction.
BUFLIM - Buffer Limit Register - (write 9Bh)
This register is used as buffer limit when
BLIMS (9Ah.4)
is high. This register can be set the buffer-ring size
minus
n
, where
n
is larger than 1. This register is 0 after master reset and firmware reset. In normal
operation, this register only needs to be set once after power-on.
BUFC - Buffer Counter - (read 9Bh)
This counter increments when a sector is buffered into external RAM. If
ACMEN (9Ch.6)
is high,
BUFC
(9Bh,r)
decrements at the end of each data-in block transfer unless the value is zero. The value follows 0 is 0.
The transfer of working area data should be implemented as linear transfer to prevent extra decrement of this
counter.
If
ACMEN (9Ch.6)
is high,
BUFC (9Bh,r)
minus
N
right after
SKIPC (9Eh)
is set
N
. This function can be used
to implement the cache-partial-hit event.
If both
BLIMEN (9Ah.5)
and
BLIMS (9Ah.4)
is high, the buffering stop when this count reaches
BUFLIM
(9Bh,w)
. The value in BUFC (9Bh,r) may exceed
BUFLIM (9Bh,w)
by one.
This counter is synchronized to
TCC (9Dh)
whenever
DECEN (0Ah.w7)
is low.
This counter is 0 after master reset and firmware reset.
ACCTL - Automatic Cache Control Register - (read/write 9Ch)
This register is 0 after chip reset, host reset and firmware reset.
Bit 7: ATTEN - Automatic Transfer Trigger Enable
The control bit
ADTT (17h.w2)
is automatically set high if all the following conditions are met:
ATTEN (9Ch.7)
is high
TCC (9Dh)
is not zero
TTC (9Fh)
is not zero