LACO PROTOCOL DESCRIPTIONS TITANTEST™
113
© 2018 LACO TECHNOLOGIES, INC. - TitanTest itra01en1-07 SB.fm - 1807
12.LD Protocol**
12.1 Communication Parameters
12.2 Command format
12.2.1 Telegram structure
Master sends
Slave answers
** Feature not available in TITANTEST™ Maintenance model
Data format
Baudrate 19.200, 8 data bits, 1 stop bit, no parity
ENQ LEN ADR CmdH CmdL DATA (n bytes) CRC
0123 4 5 5 + n
STX LEN StwH StwL CmdH CmdL DATA (n bytes) CRC
012 3 4 5 6 6 + n
Command Meaning
ENQ 0x05 Start of master request
STX 0x02 Start of slave response
LEN Number of telegram bytes without ENQ(STX)/LEN, however with CRC
max. 253, so the total slave telegram length is max. 255
ADR Slave address Slave address = 1: non-addressed bus. Address byte is ignored.
Stw H/L Status word Info from slave to master (Seite 117)
Cmd H/L Command Bit 15 ... 13: Command-specifier Read/Write etc. (see table
“Cmd H/L: Command: Command-specifier”)
Bit 12: free
Bit 11 ... 0: Command numberSeite 117)
DATA Data belonging to master request
(Slave reply to write command is
sent without data)
0 ≤ n ≤ 248
If I/O module (7-byte additional header) is used, then limit max-
imum data length to 241.
CRC Checksum Calculate CRC for all bytes (except CRC byte)
Polynomial: 0x98,
Name: DOWCRC,
Maxim/Dallas, X
8
+X
5
+X
4
+1
Info:
CRC calculation see document "CRC_calculation.c" (C souce
code)
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