I was surprised to discover that GPIO pins, just after they're configured as outputs, default LOW (the opposite state of its startup high-impedance input mode). For my design, LOW is an ACTIVE state. I can immediately set the output HIGH but I'm stuck with a LOW 'glitch' to deal with. Every other micro GPIO I've worked with would maintain the HIGH when switching from input to output mode. Just wondering if anyone knows something I don't here...I certainly can't find any Philips documentation on the issue. And I know I can design for a HIGH state and put pulldowns on the lines but, again, I hate to redo everything just to find that the initial GPIO output state is undefined or arbitrary...or, again, that there's something I dont' know about. Thanks folks,
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LPC2xxx GPIO Outputs Born LOW
2004-10-26 by markcrow
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