T8531A/T8532 Agere Systems, Inc., T8531A/T8532 Datasheet - Page 38

• Manufacturer Part Number: T8531A/T8532
• Description: Multichannel Programmable Codec Chip Set
• Manufacturer: Agere Systems, Inc.

Codec Chip Set
Software Interface
Table 27. T8532 Control Register 1: Digital Loopback
Table 28. Bit Map for T8532 All Channel Test Register at 0x1510 and 0x1550
Table 29. Bits 3:0 of T8532 All Channel Test Register at 0x1510 and 0x1550
Notes:
Read out address provides the previous read or write address to CDO whenever a new address is being written into the register.
When analog loopback is high, data that enters the analog transmit path (VTX) is converted to a 1.024 MHz digital bit stream and routed back to
the analog receive path (VRP, VRN). The output of the transmit path is available on the oversampled data interface, but receive path oversam-
pled data is ignored.
When digital loopback is high, oversampled data receive (OSDR) is routed to oversampled data transmit (OSDX). The receive signal is propa-
gated to VRN/VRP, but any transmit signal from VTX is disconnected. A reference voltage on VRTX is still required in this mode.
38
Not used
—
—
—
—
—
—
3
0
1
15—4
LPBK
Bit 0
0
1
—
—
—
—
—
—
2
0
1
Read out address
VTX
VRP
VTX
VRP
(continued)
Bit Number
3
Normal operation
Digital loopback
Mode
—
—
—
—
—
—
A/D, D/A
1
0
1
Bit Number and Function
A/D, D/A
Reserved
OVERSAMPLED
INTERFACE
2
—
—
—
—
—
—
0
0
1
OVERSAMPLED
DATA
INTERFACE
DATA
Analog loopback
1
Read out address
Normal operation
Normal operation
Normal operation
Normal operation
Analog loopback
Digital loopback
OSDR
OSDR
OSDX
OSDX
Function
Reserved
Agere Systems Inc.
Digital loopback
May 2001
0
5-5134 (F)
5-5135 (F)