r6781-12 Conexant Systems, Inc., r6781-12 Datasheet - Page 26

• Manufacturer Part Number: r6781-12
• Description: Embedded Modem Family
• Manufacturer: Conexant Systems, Inc.

2.2 Additional Information
2.1.2 Serial/Indicator Interface
2.1.3 Speaker Interface
2.1.4 Line Interface
2-12
(Addr=0 and 1, DLAB=1)
Scratch Register (SCR)
Divisor Registers
(Addr = 7)
The Divisor Latch LS Byte and Divisor Latch MS Byte are two read-write
registers at locations 0 and 1 when DLAB = 1, respectively.
hex value.
baud rate.
The Scratchpad Register is a read-write register at location 7. This register is not
used by the DSP and can be used by the host for temporary storage.
A DTE serial interface and indicator outputs are supported.
A speaker output, controlled by AT or V .25 bis commands, is provided for an
optional OEM-supplied speaker circuit.
The EmbeddedModem connects to the line interface circuitry by means of a
receive analog input, two transmit analog outputs, and a ring signal input.
interface. These outputs may be used to control relays such as off-hook, A/A1,
and talk/data.
2.2 Additional Information
Additional information is provided in the RC224ATLV Modem Designer’s Guide
(Order No. 821).
The baud rate is selected by loading each divisor latch with the appropriate
• Serial Interface: An 8-line V .24/EIA-232-D or TTL logic serial interface to
• LED Indicator Interface: Four direct connect LED indicator outputs are
The EmbeddedModem provides three relay control outputs to the line
the DTE is supported.
supported.
Table 2-2
Table 2-2. Programmable Baud Rates
Conexant
MS
01
00
00
00
lists the programmable values corresponding to the desired
Divisor Latch (Hex)
LS
C0
80
60
30
(Decimal)
Divisor
384
192
96
48
EmbeddedModem Family
D224ATLVDSC
Baud Rate
1200
2400
300
600