I2CWRITE not writing anything on PIC18F45K80

[tumbleweed]

Fair enough, but what about this when x >= 16

if topline[x]=32 or botline[x]=32 then a=0
if topline[x+1]=32 or botline[x+1]=32 then b=0 'blanker

[CuriousOne]

I don't see any relation
I modified code and X now changes from 0 to 14 - still same issue.

[tumbleweed]

You've been using x, y, and z to get values to set a and b.
You've been shoving invalid data out to the lcd and wondering why the display is wrong.

It's probably still wrong.

[CuriousOne]

LOL.
I'm trying to explain that if I add one extra array definition, another array gets screwed. How this is related to LCD?
I just wrote another code, which simply reads values of array and writes data on 1602LCD.
Issue still exists - data in array gets damaged, if total array length exceeds 24 bytes.

[tumbleweed]

I just did this with an 18F45K80

' device = 18F45K80

topline var byte [16]  'top part of the screen array
botline var byte [16] 'bottom part of screen

ix var byte
ct var byte
cb var byte

' clear arrays
for ix = 0 to 15
    topline[ix] = 0
    botline[ix] = 0
next ix

' read array data
arraywrite topline,["0123456789ABCDEF"]
arraywrite botline,["0123456789ABCDEF"]

ix = 0

'read array char by char
for ix = 0 to 15
    ct = topline[ix]
    cb = botline[ix]
next ix

ix = 0

When it gets to the end, topline and botline arrays are exactly as specified... each is 16 chars "0"-"F"
Reading the arrays byte by byte also does as expected.
I even added a third array of 16 chars... works too.

Your problem is elsewhere... not with the arrays themselves.

[CuriousOne]

Thanks, have you tried to read the same array several times?
Problem is definitely in arrays, because if I make say topline 4 bytes and botline 16 bytes (even without writing anything to any of them) - there are no problems, but as soon their total "length" exceeds 24 bytes, issues start to appear.

[richard]

Your problem is elsewhere... not with the arrays themselves.

code snippets , a complete waste of time and effort

[tumbleweed]

just saying... "Problem is definitely in arrays... but as soon their total length exceeds 24 bytes, issues start to appear. " doesn't seem to pan out.

The following reads three 16-byte arrays (48 bytes total) 20K times and verifies the arrayreads. No errors.
Same with the original two 16-byte arrays.

' device = 18F45K80

topline var byte [16]  'top part of the screen array
botline var byte [16] 'bottom part of screen
line3   var byte [16] 'more array data

ix var byte
ct var byte
cb var byte
c3 var byte

i var word
fail var word

fail = 0

for i = 0 to 20000
    ' clear arrays
    for ix = 0 to 15
        topline[ix] = 0
        botline[ix] = 0
        line3[ix]   = 0
    next ix

    ' read array data
    arraywrite topline,["ABCDEFGHIJKLMNOP"]
    arraywrite botline,["QRSTUVWXYZ[\]^_`"]
    arraywrite line3,  ["abcdefghijklmnop"]

    'read array char by char and check
    for ix = 0 to 15
        ct = topline[ix]
        if (ct-"A" <> ix) then fail = fail + 1
        cb = botline[ix]
        if (cb-"Q" <> ix) then fail = fail + 1
        c3 = line3[ix]
        if (c3-"a" <> ix) then fail = fail + 1
    next ix
next i

' check for failure
if (fail > 0) then
    i = fail
endif

Tried both PBP 3.16 and PBPL. No difference.

I just wrote another code, which simply reads values of array and writes data on 1602LCD.
Issue still exists

Post the complete code that doesn't work.