PIC18F4550 question VS PIC16F887

[mackrackit]

http://www.picbasic.co.uk/forum/showthread.php?t=543

[lerameur]

I tried it both ways MPASM and PM, and both of them do not work. I cant even compile.

I even tried to compile this program:http://melabs.com/samples/LABXUSB-18F4550/USBMOUSE.htm

I can compile if I just use in the overhead: DEFINE OSC 20 and put an external 20mhz crystal, it is somewhat working, but is not keeping the timer properly and is not showing all the letter on the LCD.

[lerameur]

Using:
DEFINE OSC 8
OSCCON = %01110000

only as the overhead and compiling:
Executing: "C:\PBP2.60\PBPMPLAB.BAT" -ampasmwin -k# -p18F4550 "both.bas"
Executing: "C:\PBP2.60\PBPW.EXE" -ampasmwin -k# -p18F4550 "both.bas"
PICBASIC PRO(TM) Compiler 2.60A, (c) 1998, 2010 microEngineering Labs, Inc.
All Rights Reserved.
Loaded C:\PBP2.60\both.COF.
BUILD SUCCEEDED: Sun Feb 20 10:22:55 2011

but the LCD is only showing black squares...

K

[rsocor01]

but the LCD is only showing black squares...

That looks like a timing issue or maybe a problem with the LCD contrast. That would be my guess. To check that the timing is correct I would try to blink an LED with let's say a 1 sec on and off interval. For the contrast issue I would use a pot to see if there are any changes. Are you using the same voltage with the PIC16F887 and with the PIC18F4550?

Robert

[lerameur]

the pins are the same on both 887 and 4550 chips. The 4550 does work with a 20mhz crystal but the timing is off. It does not record a proper time on the RTC and when I show the time on the LCD and do not pause for 1sec but a bit less then half a second and it always shows me 08:08:08:08. and the first few letters are missing on the lCD on the first line.

K

[lerameur]

I change to DEFINE OSC 40 while still using a 20Mhz crystal. The text is good on the LCD , but the timer always read 08:08:08

K

[lerameur]

Hey Dave,

when yo mentioned these settings:
@ __CONFIG _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
@ __CONFIG _CONFIG1H, _FOSC_INTOSCIO_EC_1H
@ __CONFIG _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H
@ __CONFIG _CONFIG3H, _PBADEN_OFF_3H & _MCLRE_OFF_3H
@ __CONFIG _CONFIG4L, _LVP_OFF_4L & _ICPRT_OFF_4L &_XINST_OFF_4L


should they be inside asm... endasm ? or just copy and paste ?

also in the MPLAB I have the build option: -ampasmwin -k#

K