Rockwell-automation 1775-KA PLC-3 Communication Adapter Module User Ma Instrukcja Użytkownika Pobierz pdf (Strona 220)

Detailed Flowcharts

Appendix D

D10

Figure D.11 shows the transmitter (XMIT) and receiver (RCVE) routines

sharing the transmit side of the UART. XMIT transmits messages and

inquiries. RCVE transmits responses. Therefore, each must wait until the

other is thru before it can transmit thru the UART. The TXALLOC and

TXFREE subroutines work together to ensure that XMIT and RVCE do

not try to use the UART at the same time. TXALLOC and TXFREE are

called in the SENDCTRL, SENDETX, and SENDDATA subroutines

(Figure D.12, Figure D.13, and Figure D.14).

Figure D.11

Sharing

the Transmit Side of the UART

TXALLOC

UART Usage

TXFREE

XMIT RCVE

Not–In–Use

Signal

10081–I

UART Sharing

1 2 ... 215 216 217 218 219 220 221 222 223 224 225 ... 238 239

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