Low Power V.22 bis Modem
CMX868
1.5.10.5
Tx Data Register
Tx Data Register: 8-bit write-only.
C-BUS addresses $E3 and $E4
7
6
5
4
3
2
1
0
Bit:
Data bits to be transmitted
In Synchronous Tx data mode this register contains the next 8 data bits to be transmitted. Bit 0 is
transmitted first.
In Tx Start-Stop mode the specified number of data bits will be transmitted from this register (b0 first). A
Start bit, a Parity bit (if required) and Stop bit(s) will be added automatically.
This register should only be written to when the Tx Data Ready bit of the Status Register is 1.
C-BUS address $E3 should normally be used, $E4 is for implementing the V.14 overspeed transmission
requirement in Start-Stop mode, see section 1.5.1.
1.5.10.6
Rx Data Register
Rx Data Register: 8-bit read-only.
C-BUS address $E5
7
6
5
4
3
2
1
0
Bit:
Received data bits
In unformatted Rx data mode this register contains 8 received data bits, b0 of the register holding the
earliest received bit, b7 the latest.
In Rx Start-Stop data mode this register contains the specified number of data bits from a received
character, b0 holding the first received bit.
ã 2004 CML Microsystems Plc
28
D/868/9
CMLMICRO [ CML MICROCIRCUITS ]
