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User Manual – JCM-501-E01
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8.4 Serial interface RS-232
The JCM-501-E01 has a user-programmable RS-232 interface.
8.4.1 Operating principle
The OS provides a receive buffer and a transmit buffer for the user-program-
mable serial interface. These buffers can be used to adjust the transfer rate be-
tween application program and serial interface.
Block diagram
The following illustration shows the block diagram of the user-programmable se-
rial interface:
Driver
Driver
Receiver
Transmitter
Receive-FIFO
Transmit-FIFO
T
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n
s
m
it
R
e
g
is
te
r
S
ta
tu
s
a
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d
C
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n
tr
o
l
R
e
g
is
te
r
R
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iv
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R
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1
2
3
4
5
6
7
8
9
Fig. 10:
Block Diagram - Serial Interface
Elements of the
interface
The user-programmable serial interface consists of the following elements:
Number
Section
Function
1
Interface driver
Converts the signals of the interface into in-
ternal signal levels
2
Addressee
Performs serial/parallel conversion
3
Receive buffer
Buffer for received characters
4
Receive register
Read access to this register reads the re-
ceived characters in the receive buffer (3).
5
Interface driver
Converts internal signal levels into interface
signals.
6
Transmitter
Performs parallel/serial conversion
7
Sending buffer
Buffer for characters to be sent
8
Transmit register
Write access to this register causes the char-
acters to be entered into the transmit buffer
(7) and to be sent by the transmitter (6).
9
Status and control reg-
ister
Query of filling levels and error states of buf-
fers; setting of transmission parameters
Tab. 22:
Elements of the serial interface
