Software for RS422 Multidrop Acquisition

[Dean]

Hi,

I'm brand new, so bear with me!

I need to design a multidrop RS422 system to acquire eight digital inputs at each station (drop). I'll use a type 7004 card and an NMI 8051 processor card to do that.

Is there software (preferably 8051 assembly or C language) to enable each station to respond to an inquiry addressed to it and to ignore inquiries addressed to the other stations?

Thanks in advance.

Dean

[nmitech]

I do not have any sample code for 8051. Attached the multi-drop RS-422 driver of the HC11 machine code below for your reference.
-------------------------
( ID CHAR AT B7CA
( EKEY IS AT B776
( INIT CFA IS B7B3

CREATE IM
FEAC , ( Z: DW DOCOLON
B7B3 , ( DW INIT
E6E5 , ( DW ABORT

BD C, F8CB , ( e1: JSR OLDKEY
C1 C, 01 C, ( CMPB # ^A
26 C, 22 C, ( BNE E2 IF == ^A
18 C, 08 C, ( INY POP OFF THE STACK
18 C, 08 C, ( INY
F6 C, B000 , ( LDAB PORTB TURN OFF TRANSMIT
C4 C, F7 C, ( ANDB #F7
F7 C, B000 , ( STAB PORTB
BD C, F8CB , ( JSR OLDKEY GET ADDRESS
18 C, 08 C, ( INY TAKE CHAR OFF STACK
18 C, 08 C, ( INY
F1 C, B7CA , ( CMPB B7CA B7CA IS THE ID ADDRESS
26 C, -1F C, ( BNE E1: IF NOT MY ADDRESS GO BACK TO GET CHAR
F6 C, B000 , ( LDAB PORTA TURN ON TRANSMITTER
CA C, 08 C, ( ORAB #08
F7 C, B000 , ( STAB PORTA
20 C, -29 C, ( BRA E1: GO BACK TO GET CHAR
B6 C, B000 , ( e2: LDAA PORTA CHARACTER IS NOT ^A, CHECK MODE
84 C, 08 C, ( ANDA # 08
26 C, 06 C, ( BNE E3: IF MODE NO GO
18 C, 08 C, ( INY TAKE CHAR OFF STACK
18 C, 08 C, ( INY
20 C, -36 C, ( BRA E1: GO BACK TO GET CHAR
4F C, ( e3: CLRA MODE GO, GET CHAR
C4 C, 7F C, ( ANDB # 7F STRIP 8TH BIT
18 C, ED C, 00 C, ( STD 0 ,Y
39 C, ( RTS

FE58 , ( I: DW DO-CODESUB
B6 C, B03C , ( LDAA B03C
84 C, 20 C, ( ANDA #20
26 C, 0D C, ( BNE X
CC C, B776 , ( LDD #EASYA-KEY REVECTOR KEY
DD C, 16 C, ( STD 16 BY REPLACING ITS CALL ADDRESS
86 C, 08 C, ( LDAA #8 MAKE PA3 AN OUTPUT
B7 C, B026 , ( STAA B026
B7 C, B000 , ( STAA B000
39 C, ( X: RTS CONTINUE FORTH STARTUP
-------------------

[Dean]

Thanks,

This is helpful. Can you tell me anything about the MAX-DDE software referred to in your manual for your RS422/485 products? Do you or any customers have a Windows compatible server or component for doing multidrop RS422 or RS485?

Dean

[nmitech]

You can download MAXDDE manual here,

http://www.newmicros.com/store/product_manual/Maxdde.pdf

MAXDDE software is not available for download. It comes with the purchase of the MAXDDE-Package.

http://www.newmicros.com/cgi-bin/store/order.cgi?form=prod&cat=6811