T8531 Agere Systems, Inc., T8531 Datasheet - Page 37

• Manufacturer Part Number: T8531
• Description: T8502 and T8503 Dual PCM Codecs with Filters
• Manufacturer: Agere Systems, Inc.

November 2000
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 over-
sampled 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.
Lucent Technologies Inc.
Not used
—
—
—
—
—
—
3
0
1
15—4
LPBK
Bit 0
0
1
—
—
—
—
—
—
Read out address
2
0
1
Bit Number
VTX
VRP
VTX
VRP
(continued)
3
Normal operation
Digital loopback
—
—
—
—
—
—
1
0
1
Bit Number and Function
Mode
A/D, D/A
A/D, D/A
Reserved
2
—
—
—
—
—
—
0
0
1
OVERSAMPLED
INTERFACE
OVERSAMPLED
DATA
INTERFACE
Analog loopback
DATA
1
Read out address
Normal operation
Normal operation
Normal operation
Normal operation
Analog loopback
Digital loopback
Reserved
Function
Digital loopback
OSDR
OSDR
OSDX
OSDX
0
Codec Chip Set
5-5134 (F)
5-5135 (F)
37