Crystal CS4281, Programming Manual

Page: 143 / 231

CS4281 Programming Manual
DS308PRM1 143
Confidential Draft 3/7/00
16.2.6 Sound Blaster Write Buffer Status
(SBWBS)
Address: BA0: 710h, Read-Only
I/O: C/D
SB Reset Default: 000000AAh (will change to 2Ah after delay)
POR Default: 0000002Ah (
SSCR.SB
= 0)
Definition: Write status port for Sound Blaster Command and Data write access.
Bit Descriptions:
WBB Write Buffer Empty:
0 - Next data item can be written to SBWDP
1 - Write Buffer Busy. Software must wait before writing data to SBWDP
RD[6:0] Lower 7 bits from data in SBRDP.
16.2.7 Sound Blaster Read Buffer Status
(SBRBS)
Address: BA0: 714h, Read-Only
I/O: E/F
SB Reset Default: 0000002Ah (will change to AAh after delay)
POR Default: 00000000h (
SSCR.SB
= 0)
Definition: Read status port for Sound Blaster Command and Data read access. When bit 7 is a 1, new read
data is available in the data read port. Reading this register also clears all Sound Blaster generated
interrupts.
Bit Descriptions:
RBF Read Buffer Full:
0 - Stale Data
1 - New Data available in SBRDP
RD[6:0] Lower 7 bits from data in SBRDP.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
WBB RD6 RD5 RD4 RD3 RD2 RD1 RD0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
RBF RD6 RD5 RD4 RD3 RD2 RD1 RD0
D
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ft