IDEC MicroSmart - Manual (Page 290)

17: U SER C OMMUNICATION I NSTRUCTIONS
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Transmit Data Byte Count
The data register next to the operand designated for transmit status stores the byte count of data transmitted by the TXD
instruction. When BCC is included in the transmit data, the byte count of the BCC is also included in the transmit data byte
count.
Example: Data register D100 is designated as an operand for transmit status.
Programming TXD Instruction Using WindLDR
The following example demonstrates how to program a TXD instruction including a start delimiter, BCC, and end delim-
iter using
WindLDR .
TXD sample program:
Data register contents:
Transmit data example:
1. Start to program a TXD instruction. Move the cursor where you want to insert the TXD instruction, and type TXD. You
can also insert the TXD instruction by clicking the User Communication icon in the menu bar and clicking where you
want to insert the TXD instruction in the program edit area.
The Transmit instruction dialog box appears.
D100 Transmit status
D101 Transmit data byte count
S1
12 D1
M10
I0
SOTU TXD
1 D2
D100
Communication por t: Por t 1
Transmit completion output: M10
Transmit status register: D100
Transmit data byte count: D101
04D2h D10
162Eh D11
= 1234
= 5678
STX
(02h)
D10
“1”
(31h)
“2”
(32h)
“3”
(33h)
“4”
(34h)
“5”
(35h)
“8”
(38h)
BCC
(41h)
ETX
(03h)
BCC
“6”
(36h)
“7”
(37h)
BCC calculation range
Constant D11 Constant
(H)
BCC
(36h)
(L)
(hex) (hex)