MAS7838 ETC, MAS7838 Datasheet - Page 2

• Manufacturer Part Number: MAS7838
• Description: SYNCHRONOUS TO ASYNCHRONOUS CONVERTER SAC CMOS
• Manufacturer: ETC

Top marking: YYWW = Year Week, XXXXX.X = Lot Number,
XESR
XASY
XHST
TMG
RDO
OSC
TDO
RXC
VDD
TXC
VSS
TSL
CL1
CL2
RDI
TDI
XESR
TMG
OSC
TXC
VSS
TSL
CL1
CL2
PDIP 16
10
13
14
15
16
11
12
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
MAS7838N
O
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O
O
P
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X
X
I
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Y
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Timing select. 0 selects asynchronous sampling timing 16 x TXC from pin 2, TMG.
1 selects asynchronous sampling timing 256...8192 x TXC from pin 2, TMG.
Timing. Square wave timing signal 16 x TXC (TSL=0) or 256...8192 x TXC (TSL=1).
Max f=10 MHz.
Oscillator. Output for crystal. If used, the crystal is connected between pins 2 and 3.
Transmitter timing. Synchronous square wave timing for transmitter. The transmitted
data output, TDO is synchronized to the rising edge of TXC. The duty cycle of TXC
has to be 50% +/- 5%.
Character length. The total character length including one start bit, one stop bit and
possible parity bit is selected with the CL1 and CL2 signals.
Extended signalling rate. The tolerance of the synchronous bit rate can be:
XESR = 1 (basic signalling rate) TXC -2.5%...+1.0%
XESR = 0 (extended signalling rate) TXC -2.5%...2.3%
Ground
Transmitter data input. 1 = mark or stop bit, 0 = space, start or break signal
Transmitter data output. The output data is synchronized to the synchronous timing
signal TXC (pin 4). 1 = mark, 0 = space
Asynchronous mode. XASY=0 Asynchronous transmission. XASY=1 Synchronous
transmission. In synchronous transmission the converter is totally bypassed in both
directions: TDI=TDO, RDI=RDO
Higher speed signalling timing. XHST = 1 normal synchronous to asynchronous
conversion (Bell 212; CCITT V.22). XHST = 0 asynchronous to synchronous
conversion with higher speed synchronous timing (TXC, RXC). TXC and RXC timing
must be 1-2% higher than the normal bit rate in order to allow some overspeed in the
asynchronous data. On the receiver side the RX buffer is deleted and the
synchronous data RDI is directly connected to the asynchronous output RDO.
Receiver data output. RDO is the received data converted back to asynchronous
mode.
1 = mark or stop bit, 0 = space, start or break signal
Receiver data input. 1 = mark, 0 = space. The received data must be synchronized to
the receiver timing RXC from the synchronous channel (pin 15).
Receiver timing. Receiver square wave timing from the synchronous channel. The
received data RDI must be synchronized to the rising edge of RXC.
Power supply
16 VDD
15
14
13
12
11
10
9
RXC
RDI
RDO
XHST
XASY
TDO
TDI
XESR
=ESD Indicator
SO16
TMG
OSC
TXC
VSS
TSL
CL1
CL2
1
2
5
6
7
8
3
4
MAS7838S
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Y
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16 VDD
15
14
13
12
11
10
9
RXC
RDI
RDO
XHST
XASY
TDO
TDI
20 September, 2000
DA7838.002
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