ERROR: UNABLE TO COMMUNICATE

Started by tnnflash, May 20, 2009, 06:57:45 AM

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tnnflash

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

Andy Ayre

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
Embedded Systems Academy, Inc.
support at esacademy dot com

tnnflash

#2
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