03-01-2007, 21:36
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6th Gear Developer; Mentor
AKA: Blake Ross
no team (6th Gear)
Team Role: Mentor
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Join Date: May 2006
Rookie Year: 2006
Location: Virginia
Posts: 1,940
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Re: how to build a VEX programming module
Quote:
Originally Posted by Eldarion
How do I place the Vex controller into program mode?
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If I remember correctly, you have to send it the right pulse train. That's not easy to do without some sort of active device. A high-quality voltage level-shifter can preserve the pattern produced by a computer's serial port and send the right info to the microcontroller; but computers' USB outputs and USB-to-Serial convertors are a crap shoot. Hence the valuable little circuits inside that Vex box that converts USB into TTL-level serial.
Blake
PS: Using a computer's serial port to drive only a level shifter (not using the computer's USB port) let's you download code much faster (around 2X?) than going the USB route. However, some modern PC's don't even have serial output ports...
__________________
Blake Ross, For emailing me, in the verizon.net domain, I am blake
VRC Team Mentor, FTC volunteer, 5th Gear Developer, Husband, Father, Triangle Fraternity Alumnus (ky 76), U Ky BSEE, Tau Beta Pi, Eta Kappa Nu, Kentucky Colonel
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