DA9138.005
12 April, 2006
APPLICATION INFORMATION
Data multiplexer
A third application is a data multiplexing/demultiplexing system. The system accepts data from several sources.
These data lines are sampled and the samples are sent through a multiplexer to a demultiplexer. To accomplish this,
either a very high sample rate is needed or first convert the data to synchronous mode, where synchronous
multiplexing can be used and only one sample per data bit is needed.
M AS9138
TDI
CH 1
RDO
1
TDO
RDI
RDI
TDO
1
M AS9138
RDO
TDI
M AS9138
FORWARD
CH 2
2
M AS9138
MUX/
DEMUX
BACKWARD
MUX/
DEMUX
2
CH N
N
TIMING
N
Synchronous modem with asynchronous interface
The following application shows how to add an asynchronous interface to a synchronous modem with MAS9138. TSL
and XHST inputs (pins 1 and 12) are connected to VDD. If the crystal is removed and the external 16 x TXC clock
signal is used (dotted line) then tie the TSL input to ground. CL1, Cl2, XASY and XHST are user adjustable with
jumpers or dip switches.
+5v
RS232C
TXD
TTL/V28
78189A
470pF
Synchronous
Modem
TDO
TXC
RDI
RXC
TTL-Level
TTL-Level
TTL-Level
TTL-Level
*)
22pF
TDI
16
9
10
4
14
TXC
RXD
470pF
TTL/V28
75189A
RDO
+5v
TSL
XHST
Ext. Signal Rate
Char. Length
Char. Length
ASY/SYN Select
13
15
RXC
16 x TXC
MAS9138
1
12
7
5
6
11
8
2
-12v
+12v
CR 1
9.8304MHz
3
22pF
Modem
Timing
Circuit
mode
selection
jumpers
*) Optional timing from the
synchronous modem.
In this case CR 1 can be
eliminated.
MAS9138 simplified application:
V.28 interface for synchronous modem
8 (10)
MAS [ MICRO ANALOG SYSTEMS ]
