Print Page - ERROR: UNABLE TO COMMUNICATE

Title: ERROR: UNABLE TO COMMUNICATE
Post by: tnnflash on May 20, 2009, 06:57:45 AM

Hi,

Use Flash Magic to program a P89V51RC2 in ISP Mode;

I have directly Connected the COM1 of the PC with the pins RX and TX of the microprocessor...

With the command READ DEVICE SIGNATURE is verified this error:

"Failed to read the device signature (Operation Failed...) Accesing to device using the wrong protocol..." or "UNABLE TO COMMUNICATE.(in use)..."

Who can help me?

thanks

Title: Re: ERROR: UNABLE TO COMMUNICATE
Post by: Andy Ayre on May 21, 2009, 09:16:19 AM

You can't directly connect the COM port of a PC to the RxD and TxD pins on a microcontroller. The voltages used are different and you might have damaged your device.

1. Replace your microcontroller with a new one

2. Use a MAX232 or equivalent between the COM port and microcontroller.

Andy

Title: Re: ERROR: UNABLE TO COMMUNICATE
Post by: tnnflash on May 21, 2009, 11:35:25 PM

thanks for answer... :D

now all ok ;D

Quote from: Andy Ayre on May 21, 2009, 09:16:19 AM
You can't directly connect the COM port of a PC to the RxD and TxD pins on a microcontroller. The voltages used are different and you might have damaged your device.

1. Replace your microcontroller with a new one

2. Use a MAX232 or equivalent between the COM port and microcontroller.

Andy

Flash Magic Forum

In-System Programming Support => P89V51Rx2/P89LV51Rx2 => Topic started by: tnnflash on May 20, 2009, 06:57:45 AM