Hi I am designing an amplifier where I've used I2C to communicate with two control circuit PICs (pic18f819) and then those PICs are also communicating to an-other PIC (same) via serdata serclck. The pull up voltage is 3.9 on one side of the pull-up resistors and appears 2.5 on the other side on I2c line while on ser line 2.5 on serdata and 0v on serclck. The PCB used to communicate but suddenly it is not communicating now. Is it because of 2.5 voltage appearing on I2C OR 0v on serclock OR thses pull up voltages drops dont matter ? can some one help please. I'm not sure about 2.5v on I2C and also what voltages are necessary for serdata/serclcl line ? kd

Thank you very much. kd

It is an existing PCB, contains a PIC16C771 connected to an EEPROM (X24C04) via I2C and all connected to a IDC connector via I2C. this IDC is connected to computer via DIO48 PCI I/O card. I2C connects both, PIC & EPROM directly to computer. I need to read and write data from EEPROM which is already having existing data in it. Here I need some method to connect and R/W to EEPROM using I2C from my computer. kd

How can I read /write an EEPROM on a PCB from my computer. Any help and or example plaese? kd

I am trying to communicate from my PC with a PCB using I2C. This PCB type was working but some of them are not now. I am receiving massage on my GUI control panel "I2C not connected". The problem on hardware I've found is that PIC microcontroller on PCB has 2.1v on its VSS (ground) pin. Firmware is transfered right to the PIC. I think this voltage appearing on Vss pin is creating problem. Is there any body to help me please, whether this is the problem and how to solve it please. Many thanks.

kd

Thanks a lot for help. It gave me a good clue.

kd

Actually I know designing window of control panels, I need to know programming for coms interfacing and data retrieving from external pariferals connected to PC by I2C or RS232. If you know any helping website or book please?

kd

If any body can quide me how can Control Panel designing (PC Interfacing) can be done in VC++. Any website or book for designing Control Panels to interface periferals to computer and control them and to collect data for manual test purpose please.

kd