Help needed with background recieve and pointers.

Balderbraa · Jun 11, 2013

Greetings!
Im currently working on a serial port sniffer/logger and have run into some things i dont quite understand.
Im using a 28x2 module (AXE200) with a 24LC128 eeprom and 4,7K pullup soldered to the underside of the module.
The main idea is to background recieve one series of data bytes @N4800 (max 1024bytes) and on my command transfer
these to the eeprom from scratchpad so i can transfer the values to the computer later. The data stream is
controlled by me and is only sendt once (So i guess the scratchpad never overflows if i reset the chip before making the transfer).

My setup is this:

Please note that the S1-1 to S1-4 is not implemented yet and the eeprom header is unused.

Then over to the actual programming:
Im not sure that i correctly understand the use of the pointers ptr, @ptr princ...etc.

Code:

; *************************************
; ******** Sample Header File  ********
; *************************************
;    Filename:Serial sniffer.bas 		
;    Date:11.06.2013 			
;    File Version:B 	
;    Written by: Bendik Henriksen 		
;    Function:		
;    Last Revision:
;    Target PICAXE: 28X2	
; ************************************* 


#PicAxe 28X2
#Slot 0
Setfreq em32

Symbol SW1=pinA.2
Symbol SW2=pinA.1
Symbol RDY_LED=C.0
Symbol ERR_LED=C.1
Symbol END_LED=C.2

High RDY_LED
Do while SW1=0                ;Wait for button press to continue program
                              ;,and set up background recieve
loop
Low RDY_LED


Hsersetup B4800_32,%00111                        ;Set-up for background recieve
HI2CSETUP I2CMASTER,%10100000,i2cfast_32,i2cword ;Set-up for eeprom

Main:

if SW2=1 then copy_to_eeprom ;Here it should just wait and let the background
                             ;recieve do its work.
Goto Main


Copy_to_eeprom:
ptr=0
low RDY_LED

for b0=0 to 15               ;This is the bit where i get confused. Is it
                             ;wrong to use the pointers this way, or do i
                             ;have to put the values in variables first and if
                             ;so, how can i put it into eeprom as fast as possible? 
writei2c 0,(@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc,@ptrinc)
pause 40
next b0

ptr=0

high RDY_LED

Wait_for_it:

Do while SW1=0               ;Do nothing while connecting the hserout to the computer
                             ;Move on when i press SW1 to display data in terminal.
loop

Transfer_to_terminal:
Low RDY_LED
for W1=0 to 1023
readi2c W1,(B1)
pause 40

hserout 0,(B1)
next W1

High RDY_LED
High END_LED
end

This code usally just gives out a bunch of $00 and $80 into the terminal (1024 in total) and not the bytes
i was sending to the picaxe.
Does anyone have a opinion of how i can make this thing work as i intend?

hippy · Jun 11, 2013

It looks to be okay without any in-depth analysis so perhaps break it down into separate tests before putting the whole together. You need to find which part of it is not working.

Check input switches are behaving as expected, that you are receiving all bytes and can echo those back without the eeprom, and likewise check you can write and read the eeprom with known data.

Also a better description of how this is being used would help; are you unplugging the serial cable, moving the unit from one computer to another ? Perhaps the scratchpad is overflowing or accumulating incorrect data.

Help needed with background recieve and pointers.

Balderbraa

Member

hippy

Technical Support