12f675_fuse_about_to_blow!

[LEDave]

Hi mackrackit.

My mistake, I should have said:

If the count reaches 65536ms then the Interrupt flag TMR1IF PIR.0 goes to 1 then the program jumps to:

RESET_VT

Not the DEFINE.

So when the program jumps after PIR.0 = 1 to RESET_VT it then runs the Register saving code, then the INTERRUPT routine, then restores all the previously saved values back to exactly the same condition as pre - RESET_VT. Can we come back to that part the ASM stuff later but for now assume there was some DATA received and the next block of PBP code.

Dave

[mackrackit]

Can we come back to that part the ASM stuff later but for now assume there was some DATA received and the next block of PBP code.

Yup, sounds like you have the interrupt idea worked out.
On to MAIN...

[LEDave]

MAIN:
' Fire up Timer1 before entry to serial input routine
T1CON.0 = 1

So the Timer1 is running and we've got 65.5ms to receive the data.

I guess a question here would be how fast does a PIC receive DATA? At the moment we're only receiving the SYNCH - DAT_IN1 - DAT_IN2 & CHK_SUM BYTES. If for example when the project is running and we send accumalative Bird Box Visit_Data (day1 + day2 etc.....n) then after a Month we'd have 30 Bytes or Words even, would that time_out? Because as the program stands:

T1CON.0 = 0

After the Data has arrived.

Anyway moving on.

So the Data has arrived:

SERIN2 D_IN,N2400,[WAIT(Synch),DAT_IN1,DAT_IN2,CHK_SUM]

Then:

 T1CON.0 = 0    TMR1L = 0  TMR1H = 0

So Timer1 is stopped - TMR1H&L BYTES cleared.

Before I carry on with **Begin Data Validaition**

What does the ! in: IF CheckSum ! mean please mackrackit.

Dave

[mackrackit]

Manual section
4.18. Comparison Operators
Not equal !=

I guess a question here would be how fast does a PIC receive DATA?

I think once the PIC starts receiving with SERIN2 it will not stop till finished. I will have to check to be.

[LEDave]

Manual section
4.18. Comparison Operators
Not equal !=

Cheers mackrackit, thanks for the pointer.

Dave

[LEDave]

Calculate checksum by adding 2 data bytes together

CheckSum = DAT_IN1 + DAT_IN2

So the CheckSum = (%10101011 * 2 BYTES) if SW1 ( GPIO.3) was pressed.

or (%10101101 * 2 BYTES) if SW2 (GPIO.4) was pressed.

Plus we should have the already have a calculated CHK_SUM that was sent.

So:

CHK_SUM   VAR BYTE  ' Holds checksum received

And:

CheckSum  VAR BYTE  ' Computed checksum of all bytes received

Therefore:

IF CheckSum != CHK_SUM THEN MAIN ' Failed checksum, return

If Checksum (!) is not = CHK_SUM then go back to MAIN the checksum has failed.

The same with:

IF (DAT_IN1) != (DAT_IN2) THEN MAIN ' Failed data comparison, return

The DAT_IN BYTES must also be equal, if not then back to MAIN:

If however everything matches then continue to MATCH..........

How does this look?

Dave

[LEDave]

Another question:

wsave   VAR	BYTE $5F system	   ' Saves W

Bruce's code talks of Bank0 system. Am I correct in saying that BYTE $5F system is setting bit.5 of the STATUS REG to 0 which is selecting Bank0 ($5f = %1011111).

So to change from Bank0 to Bank1 would be %1111111

Also:

movwf  wsave	 ; Save W

So these commands mean Move the contents of the W REG to the address of wsave.

Mm, not really sure about this............(more reading to do).

Dave


Dave