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FJMSoft
Joined: 20 Oct 2013
Posts: 36
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| Pullups on PIC12F675 |
 Posted: Sun Oct 20, 2013 10:01 pm |
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Hello.
I was trying to configure the pullups on PIC12F675.
What I found was using "port_a_pullups" was not working as expected.
Setting to zero pullups are off.
Setting to anything above zero then the pullups are on.
But no way to set pullup on a single port.
Looks like the command "port_a_pullups" is setting only the GPPU bit of microcontroller.
The only way I could set a single was manually declaring and setting the WPU byte using this:
| Code: |
#byte WPU = 0x95
WPU = 0b00000100; //(example)
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Am I doing something wrong?
There is a easier way to do this?
Thank you. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun Oct 20, 2013 10:25 pm |
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Always post your compiler version on a question about a suspected bug.
Last edited by PCM programmer on Sun Oct 20, 2013 11:17 pm; edited 2 times in total |
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FJMSoft
Joined: 20 Oct 2013
Posts: 36
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| Posted: Sun Oct 20, 2013 11:10 pm |
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I'm sorry, was my first post...
5.008 is this?
Thank you. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun Oct 20, 2013 11:18 pm |
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I just did a little survey. It's been broken for a long time, starting with vs. 4.132.
vs. 4.068:
| Code: |
.................... port_a_pullups(0x01);
0016: MOVLW 01
0017: BSF STATUS.RP0
0018: MOVWF WPU
0019: BCF OPTION_REG.GPPU
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vs. 4.125:
| Code: |
.................... port_a_pullups(0x01);
0016: MOVLW 01
0017: BSF STATUS.RP0
0018: MOVWF WPU
0019: BCF OPTION_REG.GPPU
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vs. 4.131:
| Code: | .................... port_a_pullups(0x01);
0016: MOVLW 01
0017: BSF STATUS.RP0
0018: MOVWF WPU
0019: BCF OPTION_REG.GPPU
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vs. 4.132 - Broken: (Since April 8, 2012)
| Code: |
.................... port_a_pullups(0x01);
0016: BSF STATUS.RP0
0017: BCF OPTION_REG.GPPU |
vs. 4.135 - Broken:
| Code: |
.................... port_a_pullups(0x01);
0016: BSF STATUS.RP0
0017: BCF OPTION_REG.GPPU
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vs. 4.141 - Broken:
| Code: |
.................... port_a_pullups(0x01);
0013: BSF STATUS.RP0
0014: BCF OPTION_REG.GPPU
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vs. 5.008 - Broken:
| Code: |
.................... port_a_pullups(0x01);
0016: BSF STATUS.RP0
0017: BCF OPTION_REG.GPPU
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vs. 5.012 - Broken:
| Code: |
.................... port_a_pullups(0x01);
0016: BSF STATUS.RP0
0017: BCF OPTION_REG.GPPU |
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FJMSoft
Joined: 20 Oct 2013
Posts: 36
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| Posted: Sun Oct 20, 2013 11:29 pm |
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Sorry friend, I'm a little new to this...
What this means?
I understood that the command "port_a_pullups" is really not working as expected.
So, how to set the pullups?
The way I said is ok?
Thank you. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Oct 21, 2013 12:05 am |
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You also need to set the GPPU bit in OPTION_REG = 0. To help you do
that, I've posted a macro that will substitute correct code for the defective
built-in function. Just place the macro code above main(), as shown below
and call the port_a_pullups() function as shown in main(). That's all you
need to fix it.
| Code: |
#include <12F675.h>
#fuses INTRC_IO, NOWDT, NOMCLR, PUT, BROWNOUT
#use delay(clock=4M)
// This macro will fix a bug by replacing the built-in
// CCS function with the following code.
#byte OPTION_REG = 0x81
#byte WPU = 0x95
#define port_a_pullups(mask) \
WPU=mask; \
if(mask) \
bit_clear(OPTION_REG, 7); \
else \
bit_set(OPTION_REG, 7)
//======================
void main()
{
port_a_pullups(1);
while(1);
}
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With that macro, it will produce this code in vs. 5.008. It's correct:
| Code: | .................... port_a_pullups(0x01);
0016: MOVLW 01
0017: BSF STATUS.RP0
0018: MOVWF WPU
0019: BCF OPTION_REG.GPPU |
I have emailed CCS Support and reported this bug to them. |
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FJMSoft
Joined: 20 Oct 2013
Posts: 36
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| Posted: Mon Oct 21, 2013 4:31 pm |
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Hello again PCM.
Friend, looks like this code need to be put in my main C file, right?
Could I put it inside 12F675.h and save it?
Looking at datasheet says GPPU set to 0 enables individual pullups, so dont need to set GPPU every time you set the pullups, code could be simplified (and faster).
| Code: |
// This macro will fix a bug by replacing the built-in
// CCS function with the following code.
#byte WPU = 0x95
#define port_a_pullups(mask) \
WPU=mask; \
//======================
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Also, can I do this?
| Code: |
#bit GPPU = 0x81.7
#define port_a_globalpullups(Pullset) \
GPPU=Pullset;
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Please give me your opinion.
I know it is a bit offtopic, but I see bit_set and bit_clear commands, there is a command so I can make a bit equal?
Something like: bit_equal(var,bit,value)
Thank you very much! |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Oct 21, 2013 5:48 pm |
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My advice is to read the 12F675 data sheet very carefully. I can't give
anything more help on this thread. I already posted a solution. |
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FJMSoft
Joined: 20 Oct 2013
Posts: 36
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| Posted: Mon Oct 21, 2013 6:04 pm |
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| Can you at least answer my question? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Oct 21, 2013 6:12 pm |
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No. Someone else can continue this. My macro exactly duplicates the
port_a_pullups() function in a working compiler. That's all I want to do. |
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FJMSoft
Joined: 20 Oct 2013
Posts: 36
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| Posted: Mon Oct 21, 2013 6:33 pm |
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| afff... thank you... |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19513
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| Posted: Tue Oct 22, 2013 1:47 am |
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PCM_programmer has completely answered your original question.
On 'bit_equal', if you look in PCM_programmers code, line starting 'if(mask', this code would be a matter of an instant, to convert into a generic version, using either a macro, or a function. Think.
On GPPU, normally pull-ups are enabled once at the start of code. |
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FJMSoft
Joined: 20 Oct 2013
Posts: 36
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| Posted: Wed Oct 23, 2013 9:27 pm |
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I thought I was having a productive conversation with PCM.
I am new to this language, I have many doubts.
I thought I could at least take the doubts related to the original question on the same topic.
If I can not, okay, no problem.
Now I understand that the code is a macro, I was thinking it could be some kind of overrided command.
But I continued with a question, can you help me?
Can I put the macro within 12F675.h then save?
So I will not need to put the macro in all my codes.
This is really a little off topic, but how can I see the code behind the command in the same way that showed PCM? (Posted: Mon Oct 21, 2013 2:18 am)
Thank you. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Wed Oct 23, 2013 10:44 pm |
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| Quote: | Can I put the macro within 12F675.h then save?
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You can do it, but you shouldn't do it. If you ever upgrade the compiler
the .h file will be over-written with the new version, losing your edits.
If you copy the .h file to your local project directory and then edit the
copy you will be sabotaging yourself if you ever upgrade the compiler.
Sometimes in newer versions of the compiler, CCS changes or expands
the meaning of the constants in the .h file. If you are using a header
file from an old version with a new compiler, you can possibly get
unstable behavior of previous working code. This happened to me once,
years ago. That's how I know not to do it.
| Quote: | | but how can I see the code behind the command ? |
Look at the .LST file in your project directory after a successful compilation.
Set the .LST file format to Symbolic or "Normal CCS Format" (ie. hex
register addresses) by going into the Project Options menu.
| Quote: |
I thought I was having a productive conversation with PCM.
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Not exactly. I was impatient to leave. I didn't want to answer questions
all afternoon. Also, I felt that reading the PIC data sheet could have
answered most of your questions, adding to my impatience. Those are
the reasons why I was abrupt. My basic attitude is that learning for
yourself is the best way, if at all possible. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Oct 24, 2013 10:32 am |
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This bug was fixed in vs. 5.013. The test program shown below now
produces this code, which is correct. The problem is solved:
| Code: |
.................... port_a_pullups(1);
0016: MOVLW 01
0017: BSF STATUS.RP0
0018: MOVWF WPU
0019: BCF OPTION_REG.GPPU |
Test program:
| Code: |
#include <12F675.h>
#fuses INTRC_IO, NOWDT, NOMCLR, PUT, BROWNOUT
#use delay(clock=4M)
//======================
void main()
{
port_a_pullups(1);
while(1);
}
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