STAC9766 Datasheet, PDF (85/97 Pages) Integrated Device Technology – TWO-CHANNEL, 20-BIT, AC’97 2.3 CODECS WITH STEREO MICROPHONE AND MIC/JACK SENSING

STAC9766/9767
TWO-CHANNEL, 20-BIT, AC’97 2.3 CODECS WITH STEREO MICROPHONE AND MIC/JACK SENSING
PC AUDIO
11. TESTABILITY
The STAC9766/9767 has two test modes. One is for ATE in-circuit test and the other is restricted for
IDT’s internal use. STAC9766/9767 enters the ATE in-circuit test mode if SDATA_OUT is sampled
high at the trailing edge of RESET#. Once in the ATE test mode, the digital AC-Link outputs
(BIT_CLK and SDATA_IN) are driven to a high impedance state. This allows ATE in-circuit testing of
the AC'97 controller. Use of the ATE test mode is the recommended means of removing the CODEC
from the AC-Link when another CODEC is to be used as the primary. This case will never occur dur-
ing standard operating conditions. Once either of the two test modes have been entered, the
STAC9766/9767 must be issued another RESET# with all AC-link signals held low to return to the
normal operating mode.
Table 32. Test Mode Activation
SYNC
0
0
1
1
SDATA_OUT
0
1
0
1
Description
Normal AC '97 operation
ATE Test Mode
IDT Internal Test Mode
Reserved
11.1. ATE Test Mode
ATE test mode allows for in-circuit testing to be completed at the board level. For this to work, the
outputs of the device must be driven to a high impedance state (Z). Internal pullups for digital I/O
pins must be disabled in this mode. This mode initiates on the rising edge of RESET# pin. Only a
cold reset will exit the ATE Test Mode.
Table 33. ATE Test Mode Operation
Pin Name
SDATA_OUT
BIT_CLK
SDATA_IN
SYNC
RESET#
No Connect
No Connect
No Connect
GPIO0
GPIO1
CID0
CID1
EAPD
SPDIF
Pin #
5
6
8
10
11
31
33
34
43
44
45
46
47
48
Function
1
Z
Z
0
1
Z
Z
Z
Z
Z
Z
Z
Z
Z
Description
Must be held high at the rising edge of RESET#
Must be held low at rising edge of RESET#
Always an input
Always an input
Always an input
IDT™
85
TWO-CHANNEL, 20-BIT, AC’97 2.3 CODECS WITH STEREO MICROPHONE AND MIC/JACK SENSING
STAC9766/9767
V 7.4 12/06