HELP on reading the data sheet/weak pull-ups

[sbobowski]

ok i have the data sheet

http://ww1.microchip.com/downloads/e...Doc/40044F.pdf

Page 25, REGISTER 4-2: OPTION_REG – OPTION REGISTER (ADDRESS: 81h, 181h)

ok i understand that bit 7 needs to = 0 to turn these on.

I have read and read and read

would someone please teach me how to read this so i know what to type in PBP
alot of people say "TRISB = %00000000"
where do you get that out of the data sheet???
and if so how do you read it, whats with the %, seems to me I'm setting individual values with that line (which is fine by me the more i learn now the better)

I'm so confused

Thanks in advance

[sbobowski]

ok i found
OPTION_REG.7=0 ' Enable weak Pull-Ups

and micro code studio accepted that.

so why does option_reg not have a # behind them
and ADCON0 Does ???

Thanks again in advance
sorry if I'm a rock

[rhino]

ok i found
OPTION_REG.7=0 ' Enable weak Pull-Ups

and micro code studio accepted that.

so why does option_reg not have a # behind them
and ADCON0 Does ???

Thanks again in advance
sorry if I'm a rock

Not sure what you mean here..... the option register is 8 bits. With the statement OPTION_REG.7=0, bit 7 of the option register (bit 7 RBPU: PORTB Pull-up Enable bit
1 = PORTB pull-ups are disabled
0 = PORTB pull-ups are enabled by individual port latch values) enables weak pullups. Also from pg. 38 section 5.2

Each of the PORTB pins has a weak internal pull-up
(≈200 μA typical). A single control bit can turn on all the
pull-ups. This is done by clearing the RBPU
(OPTION<7>) bit. The weak pull-up is automatically
turned off when the port pin is configured as an output.
The pull-ups are disabled on Power-on Reset.

. Not sure if I'm answering you question or not.

[jderson]

The data sheet in your post has no mention of ADCON0. Where did that come from?

[Archangel]

would someone please teach me how to read this so i know what to type in PBP
alot of people say "TRISB = %00000000"

TRIS = TRI STATE REGISTER so TrisA is tri state register of port A each port has 3 states,
input, output, unimplemented. Youset tris register by the bit so TrisA = %00000001 means bit zero is an input and the other 7 are outputs. You can address them individually just as easily like this TrisA.0 = 1 making PortA.0 an input. Port latches are done the same way,
example PortA = 0 all outputs low or PortA = %00000000 all portA outputs low, or PortA.1 = 1 ' portA 1 is high

and if so how do you read it, whats with the %, seems to me I'm setting individual values with that line (which is fine by me the more i learn now the better)

the % tells the compiler you are using binary. You could use decimal or hex just as well, I find binary easier because it gives a direct readout of the setting, ones are inputs zeros are outputs.

I'm so confused

Thanks in advance

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