Hi What is the code used to say port2 = port2 anded with 0x7f This will clear all bits of port 2 but bit 7? I thought it was P2 &= 0x7f this doesnt work, so i tried P2 = (P2 && x7f) This also didnt work. Anyone know what it is?
"I actually have to set the bits high because its inverted" If you want to set bits 0-6 and leave bit 7 unchanged you need to OR: P2 |= 0x7f;
I forgot to mention i'm looking for the code in c also. those 3 files dont explain the operations in c. Read up on "port latch" and you will find out what the problem is. It has nothing to do with c or assembler, it has to do with hardware erik
yeah well thats like i said, I also forgot to mention that to clear it I actually have to set the bits high because its inverted so useing what you said it would be P2 &= 7F which doesnt seem to work
P2 &= 0x80
I forgot to mention I'm looking for the code in C also. Those 3 files dont explain the operations in c.
yes, but they are irrelevant (datasheets for 1993 vintage chips) Erik
Thanks Is there more chapters? Alex
bible time here are the links to "the bible" Chapter 1 http://www.semiconductors.philips.com/acrobat/various/80C51_FAM_ARCH_1.pdf chapter 2 http://www.semiconductors.philips.com/acrobat/various/80C51_FAM_PROG_GUIDE_1.pdf chapter 3 http://www.semiconductors.philips.com/acrobat/various/80C51_FAM_HARDWARE_1.pdf Erik
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