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I'm programming on a PIC18F258 and have gotten my code to a mostly-finished state. I have to design a prototype board that gets rid of all the superfluous hardware on my HP488 development board (i.e. the LCD, the LEDs, the extra connectors) and leaves just what I need for this particular application...

Hey Ben -

After a few hours of investigation, I figured out what was wrong. It had nothing to do with pointer arithmetic, just a little quirk in the filtering protocol that I hadn't noticed. Thanks for the tech support.

According to the datasheet, setting a mask bit to 0 means that it accepts any value, regardless of the filter setting. I think there's something else going on here, but I'm not sure what. How robust is the CAN receive? I was working it pretty hard yesterday.

I'm not actually sure what it was. I think what happened was caused by running this code: void Block_All_Msg(void){ unsigned far char *reg; unsigned char i; CANCON=0x80; //Put CAN Module in Configuration Mode while(CANSTAT!=0x80); //Wait to make sure chip enters Config Mode reg=&RXF0SIDH; for(i=...

I accidentally wrote over some memory locations that I shouldn't have, and now my chip doesn't work properly. Is there a way for me to get it back to factory default settings? The chip is a PIC18f258.

Hey, I was just wondering what the state of the I/O pins is when programming through the PPP firmware. Are they driven high/low or high-impedance?

That's easier in one way, but it makes for messy code when you've got three potential transmission buffers, plus two receive buffers, which take up 13 individual registers each. That's an extra 65+ lines of code, which could be downsized into 2 for-loops if I could use pointers for the registers.

Is there some way I can set up a pointer to the TXBnCON location and then increment it as I go along? Or are the registers in the wrong part of memory for that?

I'm working with the CAN module on the pic 18f258 chip, and I'm wondering how to do a multi-register read or write. I want to be able to fill a struct or array of size 13bytes and write those bytes directly to registers TXBnCON through TXBnD7. Any suggestions on how I can do this? Better yet, do you...

Ok, thanks for the info. If you can, would you mind telling me who your manufacturer is for the onboard crystal?

Apparently either the PPP chip or or the 4052 chip isn't functioning properly, although the USB programming works fine. At any rate,the fix was easy, so problem solved. Thanks for your info.

Never mind, I figured it out. The HP-488 doesn't have a pull-up resistor on the /MCLR line, so it was just floating and causing the chip to randomly turn off. I put in a 100k pull-up and it hasn't shut off since.

Hey, I'm having a weird problem with my firmware development. It seems that no matter what code I write, my chip will run it for a while and then suddenly shut down. The LEDs all turn off, and communication comes to a halt. I've tried multiple programs doing various tasks, and the result is always t...

PIC 18F258

I don't think the chip will have a problem, because its UART baud specs include the possibility of running off a 40MHz oscillator. I was more wondering if anything else on the board (the PPP firmware or something) might object to the frequency increase.

I'm looking to replace the 20MHz crystal on my HP-488-02 development board with a 40MHz crystal. Can you tell me who your supplier is for that part so that I can get one in the same package? Also, do you know of any reason offhand why a 40MHz crystal might not work with the board?

I need information on the Bluetooth module itself - I already have the board's schematics. Since I'm doing my development in C rather than using Flowcode, I need a more intimate knowledge of how each piece works. Can you tell me if this is the correct datasheet for the Bluetooth Module? http://www.e...

What is the part number for the EZURiO module that you are using on the Bluetooth Board? Do you have schematics for it?

I've got a Bluetooth board, and was hoping to connect it to the UWTerminal application supplied by EZURiO. Is there a SOP in place for connecting the Bluetooth board directly to a computer's serial port? From your schematics, it looks like the current level shifter may not be adequate for a direct c...

What is the protocol for mallocing when programming on the PICMicro chips? I've got a line like this: char *data_array; data_array = (char *)malloc(4); When I try to compile it, I get an error saying, "Error - could not find definition of symbol 'malloc' in file './CAN.o'." I have already ...

Hello Which device are you using? Which clock speed? Which Baud rate required? I will generate you the code to drive the particular device at the particular clock speed and baud. I'm programming with an MPLAB ICD2 debugger, the board is running off the RC circuit at 3.46MHz. Any baud rate is fine f...

I'm working on a PIC18f452, plugged into the HP-488-00-3 demo board, and I'm having issues with the USART. Does anyone have C source code for a simple USART RS232 protocol demonstration? It would be nice to get some for-sure-working code so that I can test the physical setup separately from my code.

I'm not seeing anything like that in the configuration bits. Might it be under a different name? I'm actually rather skeptical as to whether the chip is being programmed at all, because it's not behaving like the code would imply. I don't know, however, whether that's a bug in the asm code or a lack...

I've got a HP-488-00-3 PICMicro development board with a PIC18F452-I/P chip which I am trying to program with the ICD2 debugger. The appropriate software is installed, I built one of the ASM example files that came with MPLAB (it was written for the 18F452 chip). The program appears to build properl...