New PICDEM2 LCD problem

[PCM programmer]

I'm going to wait until I get my new board later this week. I will then
test it and post the results. I'm not going to post anything before that.

[mindstorm88]

Hello PCM , on friday i received my lcd replacement or should i say a complete picdem2 replacement from Microchip, so before i send back the suspected defective one , i would like to confirm that it is bad!! , is it possible for you to send me by email the recommendation you got from ocular ?? so this way they won't be posted before your own testing !!

Thanks

[PCM programmer]

There are two problems.

I ordered one of the new PicDem2-Plus boards from Digikey and it
arrived last Thursday. But when I opened the package I discovered
they had sent me the old-style board (the non "Rohs update" type).
I already have two of those. So I sent the new one back on an RMA
the same day. I 've emailed Digikey to ask if they're going to send
me the Rohs version. No reply yet.

After that happened, I decided to spend some time studying the sample
driver that Ocular tech support gave me. But I found a bug.
Their status routine doesn't return the proper value of the status byte
due to a bug in the way they combine the upper and lower nybbles.
Their routine always returns 0 or 1. So when they test the top bit
for status, it's always "not busy". The execution time of the code
in the status routines probably adds up to about 40 usec with a 4 MHz
crystal, so effectively their driver is doing a fixed delay for "busy".
That's probably why it works. I emailed Ocular about this on Friday
morning but I haven't received a response yet.

[mindstorm88]

Ok , some results !!! new replacement board has exactely same behavior as the other one !!! so the problem is in the lcd design i guess , timing seem to be very sensitive , i tried another program and on power up diplay is missing few first characters , does the same just with a mclr !!!

i hope PCM you'll get yours soon !!!

[mindstorm88]

HI PCM , i did add a 5ms delay at the end of the lcd_init() , result no more missing character at power up , this display seems to be slower than standard !!!

[PCM programmer]

I tried to order the new "Rohs Update" version of the PicDem2-Plus
board from Microchip. They sent the board, but it was the OLD style
board. I already have two of those. I had to RMA it back.

So that's twice now. Neither Digikey or Microchip can supply the
new Rohs board.

Furthermore, I emailed the tech support guy at Ocular LCD and
reminded him to test his LCD driver software in 4-bit mode, with
the revisions that I recommended. He said he would try to do it,
but it's been several days now and no reply.

I am giving up. I can't get the new board, and I can't get an
answer from Ocular. I've done about all I can do.

[mindstorm88]

Funny , i got it from Digikey on my first try , then microchip send an exact replacement few weeks after for testing, up to now , not using the busy bit and adding 5ms at the enf of the init solved all problems !!!!

i guess that Microchip bought(without knowing) a defective batch !!! at least for the busy bit part !!!!

So i'm using it with dedicated driver for prototyping !!!!

[medi_pic]

Hello mindstorm88 and PCM programmer!
This problem with the initialisation of the LCD-Controller is detected.
Your LCD-moduls to work correctly. The problem is the Function "while()"
in the Compilerversion 4.xxx .
Why ? I have tested the LCD-Routine with the Compilerversion V3.0xx
and the routine functioned normal, with out problems with the LCD. In the
last week i have changed my system to V4.025 and the same LCD-Routine with the same LCD-Display no longer work correctly.
As cause of failure i was able to identify the "while()"-Function.

V3.xxx:

A FALS statment is in the input of the function -> the function is wait for change to TRUE and step out of the loop. That is correct.

A TRUE statment is in the input of the function -> the function is step over.
That is also correct.

V4.xxx:

A FALS statment is in the input of the function -> the function is wait for change to TRUE and step out of the loop. That is correct.

A TRUE statment is in the input of the function -> the function is also wait for a change from FALS to TRUE insite the function. That is not possible, because the input is already TRUE. The "while()"-function works as endless loop.

That is a bug in the new compiler version V4.0xx and not compatible with ANSII C.

[mindstorm88]

medi_pic, which while() in the driver are you talking about ???

I never had any problem with while() loop up to now !!!

[medi_pic]