How can I establish what RAM I need...and therefore which PIC.

[HenrikOlsson]

Hi Hank,
Instead of using a bunch of spaces have you tried "lining up" you columns by sending the ASCII code for TAB, I think it's 9, that might save a couple of bytes here and there.

Another option worth looking into is to use the REP modifier, these two lines:

DEBUG "Ten spaces to follow:          ", 13, 10 
DEBUG "Ten spaces to follow:", REP " "\10, 13, 10

Prints the same thing on the screen but the second takes up 6 bytes less space. Obviosuly there's a break-even point where the extra codespace needed by REP eats up more than simply spelling out the repeated characters but you get the idea.

Good luck!
/Henrik.

[HankMcSpank]

Hi Hank,
Instead of using a bunch of spaces have you tried "lining up" you columns by sending the ASCII code for TAB, I think it's 9, that might save a couple of bytes here and there.

Good luck!
/Henrik.

Just to give some feedback here - a judiscious amount of abbreviating in my original unfeasibly long debug line, coupled with use of Henrik's tab idea above - ie of boshing in a load of ,9, entries throughout debug the line vs the spaces I was using (which is also superb for lining all the onscreen info up - much easier on the eye) has seen my program wordcount plummet - (from about 4080 to circa 2200) I'm chuffed to bits.

My Uart 'VT' is somewhat irritatinlgy outputting a line with corrupt characters every 7-10 lines - could this be because my program uses two interupts ....thereby garbling the serial data a little?

[HenrikOlsson]

Hello,
DEBUG is a bit-banged serial routine that uses software loops to achieve the correct timing. If you're using interrupts they will mess with that timing.

If the interrupts aren't very critical timing wise you can disable (mask) them while executing the debug statement. If an interrupt occurs while the debug statement is executing its interrupt request flag will get set and the ISR will fire as soon as you enable the interrupt again.

The 16F690 however has a EUSART, are you using it or its pin for something else? If not you can switch to HSEROUT instead of DEBUG, that way all the baudrate generating stuff are handled by in hardware.

/Henrik.

[HankMcSpank]

Hello,
DEBUG is a bit-banged serial routine that uses software loops to achieve the correct timing. If you're using interrupts they will mess with that timing.

If the interrupts aren't very critical timing wise you can disable (mask) them while executing the debug statement. If an interrupt occurs while the debug statement is executing its interrupt request flag will get set and the ISR will fire as soon as you enable the interrupt again.

The 16F690 however has a EUSART, are you using it or its pin for something else? If not you can switch to HSEROUT instead of DEBUG, that way all the baudrate generating stuff are handled by in hardware.

/Henrik.

Thanks Henrik, looks like HSEROUT is the way to go - It looks like the 16f690 'TX' pin is pin 10 (RB7) & as luck would have it, that pin is still free in my setup - presumably I can feed the HSEROUT serial data from the PIC RB7 direct into the pickit2 & still use the Pickit2 Uart tool? (ie by feeding RB7 into Pickit2 pin 4, 'RX' pin). I'd rather go this way, as this will save me any extra wiring (I already have a switch installed to switch the Pickit2's RX pin4 back & forward between to my present nominated debug port/pin & back to pin 19 - ICSPDAT - on the 16f690 where it needs to go to program the PIC up)

[HankMcSpank]

At the risk of talking to myself, yes HSEROUT, can be 'switched' to pin4 (RX) of the Pickit2 - and characters sent via that manner displays fine on the Pickit2 Uart 2 (no garbled data anymore!)

For anyone with a 16f690, who want the settings I'm using to get HSEROUT, here you go...

@ __CONFIG _FCMEN_OFF & _INTRC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_OFF & _CP_OFF & _IESO_OFF & _BOR_OFF & _PWRTE_OFF

Include "modedefs.bas"

DEFINE HSER_SPBRG 25
DEFINE HSER_TXSTA 24h
DEFINE HSER_CLROERR 1

DEFINE OSC 4
ANSELH=0
ANSEL=0
CM1CON0 =0
CM2CON0 =0
CM2CON1 =0
adcon1=0

TRISB.7 = 0
rcsta.7=1    'this one switches 16f690's Pin 10 from RB7 (general IO) to USART TX usage- it caught me out!

loop: 
hserout ["Hello ", 13, 10]
pause 100
goto loop
end

Set your Pickit2 UArt tool baud setting to 9600 - away you go!

[HankMcSpank]

Now I'm sure this is going to be embarrasingly obvious/simple, *but*

I'm using a 16F1824, the spec says the following...

"Up to 8 Kbytes Linear Program Memory"

however, when I compile my program & goes above 4096 (as shown in microcode studio) I get an error "ARGUMENT OUT OF RANGE" ....if I strip some code out, to take it below 4096...then all is well again.

So where has the extra 4k of programming space gone?!! ie how can I can take advantage of it?!

[rsocor01]

Microcode Studio shows that number, the 4096, in words (2 bytes) for the 16F series. However, for the 18F series Microcode Studio shows that number in bytes. Don't ask me why.....

Robert