Author Topic: ERROR: UNABLE TO COMMUNICATE  (Read 6706 times)

tnnflash

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ERROR: UNABLE TO COMMUNICATE
« 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

Andy Ayre

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Re: ERROR: UNABLE TO COMMUNICATE
« Reply #1 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
Embedded Systems Academy, Inc.
support at esacademy dot com

tnnflash

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Re: ERROR: UNABLE TO COMMUNICATE
« Reply #2 on: May 21, 2009, 11:35:25 pm »
thanks for answer... :D

now all ok  ;D

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
« Last Edit: May 22, 2009, 07:27:21 am by tnnflash »