Another AXE-033 LCD question

I'm having some problems getting a full picture of how the LCD and the cursor works.

I've looked at the entry in Manual 3 about scrolling etc, but I'm still struggling with some of the behaviour.

Suppose I write some characters to the second line

serout 0, t2400, (254, 192, "1234")

I then want to overwrite the first character with the $ sign

serout 0, t2400, (254, 192, "$")

This results in the following

$ 34

with what looks like the cursor having moved to position 193, overwriting the character there with a blank, after '$' was printed at 192.

So effectively you can't address the LCD locations individually but need to overwrite a whole line?

I notice that this behaviour is the same whether or not the cursor is switched on.

I'd be interested to know if this is a property of the AXE-033 interfacing itself rather than a property of the LCD component, I imagine that it might be.

You should be able to write each character separately by itself without the space. It sounds like you may have altered the cursor operation, or have a space in your program line.

Have a look at page 5 of
www.rev-ed.co.uk/docs/led008.pdf

This shows how to play with the cursor.

Technical said:

You should be able to write each character separately by itself without the space. It sounds like you may have altered the cursor operation, or have a space in your program line.

Have a look at page 5 of
www.rev-ed.co.uk/docs/led008.pdf

This shows how to play with the cursor.

Click to expand...

This is interesting, I can see how some of the commands in the Axe-033 manual relate.

Entry Mode Set - Appears to determine if the cursor is automatically moved when a character is input.

This might be what I need, thought that table is a bit cryptic. Its pretty easy to map some of the control codes in the AXE-033 docs to it, but the ones I want are a little tricky. Looks like I'll need to experiment.

DB2=1 DB1=1/D DBO=S I get that DB0 should be zero, not sure what to do with DB2, so I'll have to experiment

Thanks for putting me on to this doc.

Bugs?

I think that there are bugs, at least in the Picaxe VSM simulation of the AXE-033

1) Cursor Left does not work at all (should be serout, 0, (254, 16)
2) All character write operations cause a movement to the right with a blanking out of the character at the right to the write position.

The cursor can be moved to an absolute position and to the right.

I've dismissed the entry set stuff as its related to direction of printing and/or scrolling neither of which is relevant.

Heres a bit of code. Note that it can't be run in the program editor simulator as the LCD in there doesnt support the cursor commands. It can be run in Picaxe VSM with the 28X1

I'll have to wait until I can run it on the hardware to see if this is just the simulator, or the behaviour of the hardware.


'------------------
' PROGRAM START
'------------------
' init
'
init:
'clear the display

serout 0, t2400,(254, 1)
pause 500

' start of the line
'serout 0,t2400,(254,128)
'pause 500

serout 0,t2400,(254,128, "1234567890ABCEDF")
pause 1000

'next line
serout 0, t2400, (254, 192)
pause 1000

serout 0,t2400, (254,192, "1234567890ABCEDF")
pause 1000

'cursor on
serout 0,t2400, (254, 14)
pause 1000

'flash
serout 0,t2400, (254,13)
pause 1000

'move to start of the line
serout 0, t2400 , (254, 191)
pause 1000

'print a character at the start
' ALSO overwrites character at 193.
serout 0, t2400 , (254, 192, "$")
pause 1000

pause 20000

Yes quite possible - the VSM model is a beta.
In the future please say you are using a simulation and not the real device in your first post!