Author Topic: Difference betw Port Pin and latch  (Read 4404 times)

clony

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Difference betw Port Pin and latch
« on: January 23, 2007, 03:57:54 pm »
Trying to configure the port pins of P89LPC935. I see there is Open Drain, Push Pull, Quasi Bi, Input Only. Great.
Now i just want to make my pins an output so i set it as Push pull. What is the difference between Port Pin and Port Latch?

Is port pin the physical value i put in software (1 or 0)? If so how does Port latch affects it? For example in Quasi -Bi, it talks about strong and weak pull ups etc depending on levels at the Port Latch and Port Pin.

Can someone clarify this for me or point me to the right information?

Thanks

erikm

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Re: Difference betw Port Pin and latch
« Reply #1 on: January 24, 2007, 05:31:22 am »
What is the difference between Port Pin and Port Latch?

1) wrong forum - what does this have to do with FlashMagic

2) read "the bible" if you are not familiar with "the bible" you will be genarlly lost whatever you do with any '51 derivative

Erik
here are the links to "the bible"
Chapter 1 - 80C51 Family Architecture:
http://www.nxp.com/acrobat_download/various/80C51_FAM_ARCH_1.pdf

Chapter 2 - 80C51 Family Programmerís Guide and Instruction Set:
http://www.nxp.com/acrobat_download/various/80C51_FAM_PROG_GUIDE_1.pdf

Chapter 3 - 80C51 Family Hardware Description:
http://www.nxp.com/acrobat_download/various/80C51_FAM_HARDWARE_1.pdf

erik