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Topics - marquisparent

#1
P89V51Rx2/P89LV51Rx2 / Re: Debugging ISP Problems
November 20, 2009, 09:04:36 AM
I notice a talk about the crystal freq.

Im using a P89V51RB2 and RC2, and its not possible to change the Oscillator Frequency.
I`m running a 12mhz at this point and my comm doesn`t work.
it seems like im have a U coming in....i have to hook it up to hyper terminal to see if its a U.

Should I use a 11.0592Mhz crystal?
#2
P89V51Rx2/P89LV51Rx2 / Programming of a P89V51RB2FN
November 15, 2009, 12:23:30 PM
I recently purchased a P89V51RB2 Mirocontroller. I am new to the ISP programming interface.  (i used to program 80c51 chip using an external EPROM)   I purchased the USB-ICP–80C51ISP interface to program the chip.  Using the Flash Magic software, I can't communicate with device. "Fail to read device signature (unabled to communicate(transmit/receive))"
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Here's my actual communication  setup:
USB-ICP-80C51ISP -->  P89V51RB2

RXD                     -->  RXD
TXD                     -->  TXD
PSEN                   -->   PSEN
Reset                   -->  RST
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Microcontroller connection.
I have a regulate 5vDC (VDD) to pin 40, gnd to pin 20.  i have a 10uF - cap from VDD to pin 9 (RST) and a 8.2kΩ - resistor to GND.  i also strapped the EA pin to VDD.
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Am i missing something ?  Do i need to use the CTS/RSt in option?
thanks for the help.