Stupid array question

[paul borgmeier]

As Sayzer is hinting, if your data does not change after you do the initial programming, you could use the LOOKUP or LOOKUP2 command. (or just the READCODE command referenced below if you preloaded your data)

If your data is going to change, you could use WRITECODE and READCODE. Also see: http://www.picbasic.co.uk/forum/showthread.php?t=137 for reference

[RUBiksCUbe]

The READCODE command actually looks perfect for me. Thanks for pointing that out.

The PIC will switch between different messages when external buttons are pushed.

[RUBiksCUbe]

Well, it was too good to be true. Whenever I compile with this in my project:

Asm
CODE 1400
DB 0
DB 220
DB 476
DB 384
DB 384
DB 476
DB 220
DB 0
DB 999
Endasm

I get some nice errors:

Found directive in column 1. (CODE)
Directive only allowed when creating an object file
Found directive in column 1. (DB)
Argument out of range. Least significant bits used.

There are 15 errors total, but they're all just copies of those 4.

Am I missing something?

[paul borgmeier]

You need to indent your program like that below. However, I believe DB is used for bytes only and you must use packing to place the word (i.e., DB 476 will not do what you want)? Others with more 16 bit processor Assembly experience might be able to offer a (better) solution in ASM.

You might want to consider using PBP's WRITECODE instead of the ASM for the initial write. Look here http://www.picbasic.co.uk/forum/show...ight=writecode and also search “WRITECODE” on this forum for examples of how to write to the 18F family, which is not as straight forward as one might think.

Asm
     CODE 1400
     DB 0
     DB 220
     DB 476
     DB 384
     DB 384
     DB 476
     DB 220
     DB 0
     DB 999
Endasm

Good Luck

edit: or consider LOOKUP2 tables

[sayzer]

..........or consider LOOKUP2 tables

I also was going to suggest LOOKUP table but arrays can not be used with Lookup tables!
Say there are 90 messages.

'This code is just a part of the idea to start from somewhere.


Message     var byte[90]
MessageTemp var byte
Loop        var byte


for loop = 0 to 89
    lookup loop,[$AA,$2C,$4D,.....................], MessageTemp
    message[loop]=messageTEMP

next loop

This way,

........

Can you do anything like that in PBP? It would make coding much easier, as opposed to going like this:
message[0] = $AA
message[1] = $2C
message[2] = $4D

and so on...

can be achieved.


------------------------------------



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[RUBiksCUbe]

I never knew about LOOKUP, but the lookup and loop should work perfectly. The intenting fixed the "DB"s but the "CODE" line still causes a problem, so I'm going to abandon READCODE and just stick with LOOKUP.

Thanks!

[SteveB]

There have been a number of solutions to this type of problem. If the messages you plan on displaying won't be changed once the pic is programmed, These may work:

STRINGS - How to store and retrieve strings in Code Space by Darrel Taylor.

Here is a thread which deals with the storage of strings as well.


One other possibility is use an external EEPROM. Limit all the messages to X number of characters (say 255). Then, depending on the message, go to the designated starting address for that message (0 for message A, 256 for message B, ...) Also store a "stop" character to know where the message ends. This would allow something like (This is an example, not a completed program):

MessageString VAR BYTE[256]
StartAddress  VAR WORD
cnt           VAR BYTE
StopChar      CON 3

MessageNumber = 1
StartAddress = MessageNumber * 256
cnt = 0
ReadMessage:
     I2CREAD DataPin,ClockPin,Control, (StartAddress+cnt) ,[MessageString(cnt)]
     IF MessageString(cnt) <> StopChar THEN ReadMessage

HTH,
Steve

EDIT: Added varible declaration for StartAddress