STAC9750 Datasheet, PDF (54/73 Pages) Integrated Device Technology – VALUE-LINE TWO-CHANNEL AC’97 CODECS

STAC9750/9751
VALUE-LINE TWO-CHANNEL AC’97 CODECS
PC AUDIO
6.5.26.
GPIO Access Register (74h)
Default: 0800h
D15
EAPD
D7
D14
Reserved
D6
D13
GPIO1
D5
D12
D11
GPIO0 EAPD_OEN
D4
D3
Reserved
D10
Reserved
D2
D9
D8
GPIO1_OEN GPIO0_OEN
D1
D0
Table 39. GPIO Access Registers (74h)
Bit(s)
15
14
13
12
11
10
9
8
7:0
Reset Value
0
0
0
0
1
0
0
0
0
Name
EAPD
Reserved
GPIO1
GPIO0
EAPD_OEN
Reserved
GPIO1_OEN
GPIO0_OEN
Reserved
Description
EAPD data output on EAPD when bit D11 = 1
EAPD data input from pin when bit D11 = 0
Reserved
GPIO1 data output on GPIO1 when bit D9 = 1
GPIO1 data input from pin when bit D9 = 0
GPIO0 data output on GPIO0 when bit D8 = 1
GPIO0 data input from pin when bit D8 = 0
0 = EAPD data out disabled
1 = EAPD data output enabled
Reserved
0 = GPIO1 data out disabled
1 = GPIO1 data output enabled
0 = GPIO0 data out disabled
1 = GPIO0 data output enabled
Reserved
The GPIO Access Register requires that the output enable bits (D11, D9 and D8) be used in con-
junction with the data source selection (input or output) for the EAPD, GPIO0 and GPIO1 (pins 47,
43 and 44 respectively). For example, to use GPIO1 as an output, set D9 = 1 to enable the output,
and use D13 to write the output value desired. To use GPIO1 as an input, set D9 = 0 to disable the
output, and use D13 to read the input value.
6.5.27.
High Pass Filter Bypass (Index 76h and 78h)
The High Pass Filter Bypass register (index 78h) is a locked register and can only be properly written
and read from when ABBAh has been written into register 76h. Bit D0 controls the High Pass Filter
Bypass. Default is zero which provides for normal operation where the high pass filter is active. Writ-
ing a one, will disable, or bypass the ADC high pass filter.
6.5.27.1. 78h Enable (76h)
Default: 0000h
D15
D14
D13
D12
D11
D10
D9
D8
EN15
EN14
EN13
EN12
EN11
EN10
EN9
EN8
D7
D6
D5
D4
D3
D2
D1
D0
EN7
EN6
EN5
EN4
EN3
EN2
EN1
EN0
IDT™
VALUE-LINE TWO-CHANNEL AC’97 CODECS
54
STAC9750/9751
V 5.8 103106