Dangerous Prototypes

Dangerous Prototypes => Bus Pirate Support => Topic started by: Rslmanu on September 21, 2009, 09:15:15 pm

Title: How to use UART ?
Post by: Rslmanu on September 21, 2009, 09:15:15 pm
Hi,

I'm trying to communicate with my bus pirate by UART (at 9600/8/n/1).
I have connected together a pickit2 (I'm using the "UART tool" on the pickit2 software to communicate using the pickit2) and the Bus pirate. The pickit2 need a 0-5V communication. So I have enabled the pull-up resistor on the bus pirate. But the menu don't give the choice of a resistors value, and I don't know if the resistor pulls up to the 3.3V or to the 5V.
I have connected the MOSI pin to the RX pin of the pickit2, the MISO to the TX, and the ground together.
But I cannot communicate. What is wrong ?

Besides, I thought there was a baud rate detector on the bus pirate. Am I wrong ? If not, how can I use it ?

Thanks for your help, and sorry for my "noob" questions !
Title: Re: How to use UART ?
Post by: ian on September 22, 2009, 07:52:36 am
@rlsmanu - Auto baud rate detector is a recently proposed feature, nobody has worked on it or committed to coding it.

Please check the Bus Pirate manual for all macros and commands. The manual also describes the pull-up resistor system on the Bus Pirate: you need to connect the Vpullup pin to a voltage source to feed the on-board 10Kohm resistors. However, if the pickit2 can register a 'high' with only 3.3volts, then you can use normal pin outputs instead of an open drain configuration.

http://dangerousprototypes.com/bus-pirate-manual/ (http://dangerousprototypes.com/bus-pirate-manual/)
http://dangerousprototypes.com/bus-pirate-manual/#uart (http://dangerousprototypes.com/bus-pirate-manual/#uart)
http://dangerousprototypes.com/2009/07/ ... resistors/ (http://dangerousprototypes.com/2009/07/27/bus-pirate-practical-guide-to-pull-up-resistors/)
http://hackaday.com/2009/07/01/mixed-vo ... us-pirate/ (http://hackaday.com/2009/07/01/mixed-voltage-interfacing-with-the-bus-pirate/)

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