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Programming | 8
JCM-631 User Manual
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Receiving a
character
Receiving a character is done in 4 steps:
Step
Description
1
The interface driver converts signals "on the line" into internal signal
levels and forwards them to the receiver.
2
The receiver performs serial/parallel conversion of this character and
checks the set communication parameters.
3
The receiver enters the character into the receive buffer if there is any
place left. Otherwise, the character is discarded and buffer overflow is
signaled.
4
Via receive register the character can be read out of the receive buf-
fer.
Sending a
character
A character is sent in 4 steps:
Step
Description
1
Via transmit register the character is entered into the transmit buffer if
there is any place left. Otherwise the character is discarded.
2
Once the transmitter has sent a character, it reads the next character
from the transmit buffer.
3
The transmitter performs parallel/serial conversion and sends this
character to the interface driver using the set communication parame-
ters.
4
The interface driver converts internal signal levels into the various in-
terface standards
8.6.2 Registers - Description
This chapter describes the registers associated with the user-programmable se-
rial interface. These registers are used for the following tasks:
■
Parameterizing the interface
■
Sending characters
■
Receiving characters
Register numbers
The registers of the interface are combined into one register block. The basic reg-
ister number of this block is dependent on the device.
Device
Basic register number
Register numbers
JCM-631
103000
103000 … 103019
for COM 1 on X71
103100
103100 … 103119
for COM 2 on the service
connector
Tab. 32:
Register numbers of the serial interface
Determining
register numbers
In this chapter, only the last two figures of a register number are specified. e.g.
MR 14. To calculate the complete register number, add the basic register number
of the corresponding device, e.g. 103100, to the module register number.
