AN93
Rev. 1.4
127
U7C is a bit-mapped register with bits 15:5 and bits 3:1 reserved. U7C resets to 0x0000 with a power-on or manual
reset.
Bit 4 (RIGPO) is output on RI pin when U7C [0] (RIGPOEN) = 1. This allows the RI pin to be configured as a
general-purpose output pin under host processor control.
The RI pin must not pulled down. Doing so forces the
modem to enter an undocumented emulation mode.
Bit 0 (RIGPOEN)=0 (default) allows the RI pin to indicate a valid ring signal. When Bit 0 = 1, RI outputs the value of
RIGPO (See Table 91).
U7D is a bit-mapped register with bits 13:9 and bits 8:2 reserved. U7D resets to 0x4001 with a power-on or manual
reset.
Bit 15 (RXWAIT) = 1 disables the UN-OBTAINABLE NUMBER response. This response can happen when there is
music after a DTMF attempt. (In China it is not uncommon to have music for ring back.) Bit 15 = 0 disables this
feature.
Bit 14 (NLM) = 0 (default) causes the modem to automatically detect loop current absence or loss. When bit
14 = 1, this feature is disabled.
13
V29EM
Use EM shielding to change direction of half duplex V.29FC.
0 = EM shielding
1) <EM><rrn>=<0x19><0xBC> to receive a V29FC packet.
2) <EM><rtn>=<0x19><0xBD> to send a V29FC packet.
1 = RTS pin toggle.
12
Reserved
Read returns zero.
11
ARMLO
0
=
Normal operation.
1 = Accomodate remote modem with large clock offset, such as 340 ppm. May degrade
training for normal modems; enable only when necessary.
10:8
Reserved
Read returns zero.
7
DOP
0
=
Normal ATDTW operation.
1 = Use ATDTW for pulse/tone dial detection (see "6.10. Pulse/Tone Dial Decision" on page
181 for details).
6
ADD
Adaptive Dialing.
1 = Enable
0 = Disable
5
Reserved
Read returns zero.
4
NEWFC
New V.22 handshake enable. This bit is mutually exclusive with bit 0. This bit makes hard-
coded U80 timing unnecessary. Without this bit, the appropriate value in U80 is required.
3:2
Reserved
Read returns zero.
1
HDLC
Synchronous Mode.
0
=
Normal asynchronous mode.
1 = Transparent HDLC mode.*
0
FAST
Fast Connect. This bit is mutually exclusive with bit 4; only one bit can be enabled at a
given time.
0
=
Normal modem handshake timing per ITU/Bellcore standards.
1 = Fast-connect modem handshake timing.*
Table 90. U7A Bit Map (Continued)
Bit
Name
Function
*Note:
When HDLC or FAST is set, the \N0 (Wire mode) setting must be used.
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 ...