SI2400 Datasheet, PDF (50/76 Pages) List of Unclassifed Manufacturers – V.22BIS ISOMODEM™ WITH INTEGRATED GLOBAL DAA

Si2400
Register E4. Chip Functions 5
Bit D7 D6 D5 D4 D3 D2 D1 D0
Name NBCK SBCK
DRT
GPE
APO TRSP
Type R
R
R/W
R/W
R/W R/W
Reset settings = 0000_0000
Bit
Name
Function
7
NBCK
9600 Baud Clock (Read Only).
6
SBCK
600 Baud Clock (Read Only).
5:4
DRT
Data Routing
0 = Data mode, DSP output transmitted to line, line received to DSP input
1 = Voice mode, selected AIN transmitted to line, line received to AOUT
2 = Loopback mode, RXD through microcontroller (DSP) to TXD. AIN looped to AOUT.
3 = Codec mode, data from DSPOUT to AOUT, selected AIN to DSPIN
3
GPE*
GPIO1 Enable.
Enable GPIO1 to be HDLC end-of-frame flag.
2
Reserved Read returns zero.
1
APO
Analog Power On.
Power on analog ADC and DAC.
0
TRSP* TXD2/RXD2 Serial Port.
Enable TXD2/RXD2 serial port so that TXD2 is GPIO1 and RXD2 is GPIO2.
*Note: GPE and TRSP are mutually exclusive. Only one can be set at any one time, and they override the settings in registers
GPIO2 and GPIO1. Once TXD2 and RXD2 are enabled through TRSP = 1, the primary serial port TXD and RXD no
longer function and pins TXD2 and RXD2 control the Si2400. This feature allows a second microcontroller to control
the Si2400.
50
Rev. 0.95