
AN93
Rev. 1.4
117
Table 77. U66 Bit Map
Bit
Name
Function
15:7
Reserved
Read returns zero.
6
FDT
Frame Detect.
0 = ISOcap frame lock not established
1 = ISOcap frame lock established
5:0
Reserved
Read returns zero.
Table 78. U67 Bit Map*
Bit
Name
Function
15:14 Reserved Read returns zero.
13:12 MINI[1:0]
Minimum Operational Loop Current.
Adjusts the minimum loop current at which the DAA can operate. Increasing the minimum oper-
ational loop current can improve signal headroom at lower Tip-Ring voltages.
MINI[1:0] Min Loop Current
00
10 mA
01
12 mA
10
14 mA
11
16 mA
11:10 Reserved Read returns zero
9
ILIM
Current Limiting Enable.
0 = Current limiting mode disabled.
1 = Current limiting mode enabled. This mode limits loop current to a maximum of 60 mA per
the legacy TBR21 standard.
8
Reserved Read returns zero.
7
DCR
DC Impedance Selection.
0 = 50
dc termination slope is selected. This mode should be used for all standard
applications.
1 = 800
dc termination is selected.
6
OHS
On-Hook Speed.
See OHS2.
5:4
Reserved Read returns zero.
3:2
DCV[1:0]
Tip-Ring Voltage Adjust.
These bits adjust the voltage on the DCT pin of the line-side device, which affects the Tip-Ring
voltage on the line. Low-voltage countries should use a lower Tip-Ring voltage. Raising the Tip-
Ring voltage can improve signal headroom. DCV has no effect on the RX signal gain.
DCV[1:0] DCT Pin Voltage
00
3.1 V (TX output level reduced by 4 dB)
01
3.2 V (TX output level reduced by 2 dB)
10
3.35 V (normal TX output level)
11
3.5 V (normal TX output level)
1
RZ
Ringer Impedance.
0 = Maximum (high) ringer impedance.
1 = Synthesize ringer impedance.
Содержание Si2404
Страница 2: ...AN93 2 Rev 1 4 ...
Страница 27: ...AN93 Rev 1 4 27 Figure 7 Parallel Interface Read Timing Figure 8 Parallel Interface Write Timing ...
Страница 200: ...AN93 200 Rev 1 4 Figure 31 TAM Handset and Speakerphone Voice Paths ...
Страница 201: ...AN93 Rev 1 4 201 Figure 32 Si3000 Codec Gain and Signal Selection Options ...
Страница 290: ...AN93 290 Rev 1 4 Figure 57 256 Band Spectral Display Figure 58 2048 Band Spectral Display ...
Страница 305: ...AN93 Rev 1 4 305 Figure 76 Parallel or SPI Port Interrupt Service Flowchart ...