Advance Information

MT91L60/61

17

Figure 10 - Loopback Signal Flow

C-Channel Register

ADDRESS = 05h WRITE/READ

Power Reset Value

1111 1111- write

76543210

C7

C6

C5

C4

C2

C1

C0

C3

Micro-port access to the ST-BUS C-Channel information read and write

XXXX XXXX - read

D7-D0

Data written to this register will be transmitted every frame, in channel 0, if the DEn control bit is set (address 04h).

Received D-Channel data is valid, regardless of the state of DEn. These bits are valid for ST-BUS mode only and are

accessible only when IRQ indicates valid access.

D-Channel Register

ADDRESS = 06h WRITE/READ

Power Reset Value

1111 1111- write

76543210

D7

D6

D5

D4

D2

D1

D0

D3

XXXX XXXX - read

PCM/ANALOG This control bit functions only when loopen is set high. It is ignored when loopen is low.

For loopback operation when this bit is high, the device is configured for digital-to-digital loopback operation. Data on

Din is looped back to Dout without conversion to the analog domain. However, the receive D/A path (from Din to

HSPKR

M

path (from M

loopen

When high, loopback operation is enabled and the loopback type is governed by the state of the PCM/ANALOG bit.

When low, loopbacks are disabled, the device operates normally and the PCM/ANALOG bit is ignored.

Loopback Register

ADDRESS = 07h WRITE/READ VERIFY

Power Reset Value

XXXX 0000

76543210

--

--

-

PCM/

loopen

-

ANALOG

Dout

M +/-

HSPKR +/-

Dout

Din

HSPKR +/-

Analog Loopback

Digital Loopback

PCM/ANALOG = 0

loopen = 1

PCM/ANALOG = 1

loopen = 1

Note: Bits marked "-" are reserved bits and should be written with logic "0"