pic18f4525

[tony]

Hello,
i have a problem about PIC18F4525.
On devices supported CCS, 18F4525 has:
ROM RAM I/O
24576 4096 36
On site Microchip, 18F4525 has:
ROM RAM I/O
49152 3968 36

What is it possible?

Besides, i have MPLAB 6.60 and CCS 3.174 and i haven't the library of 18f4525. What can you do for to use the PIC18F4525?

Thanks

[Ttelmah]

The big difference in the first numbers, is between 'bytes', and 'words'. CCS, are quoting the number of words of program memory (how many instructions it can efectively store), while the figure you are looking at on the MicroChip site, is the number of bytes (it does carefully say this in brackets).
The 'memory space', is 4096 locations, but there are only 3968 useable locations, since the rest are used by the internal registers of the chip. The CCS figure is the entire 'space' they have to handle, while the MicroChip figure is the amount of useable RAM. If you look at the 'map', in device editor, you will find the top 128bytes are flagged as already used.
Both sets of figures are 'right'.

Best Wishes

[Guest]

Ok, thank a lot but i have MPLAB 6.60 and CCS 3.174 and i haven't the library of 18f4525. What can you do for to use the PIC18F4525?
Thanks in advance

[dyeatman]

To support that chip you have to upgrade the compiler. Just having the header file won't help. The chip support for custom features related to that chip is built into the compiler.

[Guest]

Thank you very much!

[Tony]

Hello everyone,
i upgraded the compiler with header file 18f4525.h but when i'm connecting to MPLAB ICD2, the ICD self test failed.
Why?
I'm seeing ICD2 Settings (status tab) and results:

Target Vdd Pass! OK!
Module Vpp HIGH????
MCLR Gnd Pass! OK!
MCLR Vdd Pass! OK!
MCLR Vpp HIGH????
WHy?

Thank in advance!
Tony

[PCM programmer]

The wording of your sentences has put some questions in my mind.

Here you say,

[tony]

i copied into the c:\Program Files\Picc\ the files pcb.crg, pch.crg, pcm.crg
and ran pcwhupd.exe.
I think that is upgrade of compiler. In fact the release of CCS is last 3.224.

Besides i have the Microchip ICD2 for MPLAB and there is not problem when i'm connecting with PIC18F452.

[PCM programmer]

OK. That clears up those questions of mine.

Your post is basically about a problem with using the ICD2,
so the answers are probably found on the Microchip forum.
I went to their search page, and searched "All Topics" for the
"Exact phrase" of: MCLR High
http://forum.microchip.com/search.asp
Here are some posts which describe that problem:

In this post, the problem was caused by rotating the PIC 90 degrees
and wiring it up completely wrong.
http://forum.microchip.com/tm.asp?m=89438

In this post, the problem is probably caused by not using the
latest firmware for the ICD2. You're using vs. 6.60, which is fairly old.
You should upgrade to vs. 7.10 and download the latest firmware into
your ICD2, and try it again.
http://forum.microchip.com/tm.asp?m=8427&mpage=1&key=mclr+high&anchor#8431

Here's another post where a firmware upgrade for the ICD2 was
needed to fix the problem.
http://forum.microchip.com/tm.asp?m=9517&mpage=1&key=vpp+high&anchor#9517

[tony]

I upgraded the release of MPLAB from 6.53 to 7.10 and now it works!
Thanks a lot!!!

[tony]

Hello,
unfortunately i have got another problem.

MPLAB 7.10 and CCS 3.224

I have to transmitter a data packet in synchronous Master mode.

The same routine works with PIC18F452 but not with PIC18F4525.
That means with PIC18F4525 the routine appears blocked and doesn't advance as index of byte transmitted.
Why? Can you help me?

Thanks in advance.

[ckielstra]

[tony]

#include <18f4525.h>
//#include <18f452.h>


#int_tbe
void tbe_isr()
{
disable_interrupts(INT_TBE);
TXREG=0x55;
indByte ++;
enable_interrupts(INT_TBE);
return;
}


void main()

{

while (TRUE)
{
BRG16 = LOW;
SPBRG = 207;
SYNC = HIGH;
SPEN = HIGH;
CSRC = HIGH;
TXIE = HIGH;

TXREG=0x55;
indByte = 0;

while (indByte < 5)
{
TXEN = HIGH;
}
TXEN = LOW;
}

return;
}

This code works with PIC18F452 and doesn't work with PIC18F4525, that is the debugger remains in the loop (while (indByte <5)) with indbyte always = 1 and doesn't go on.
Why?
MPLAB is 7.10 and CCS, just buyed, is 3.224.
Maybe, are there the bugs in ccs 3.224 with 18f4525?

Thanks a lot in advance
Tony