| View previous topic :: View next topic |
| Author |
Message |
championx
Joined: 28 Feb 2006
Posts: 151
|
| 16F1847 comparator |
 Posted: Fri Apr 18, 2014 10:57 am |
 |
|
Hi all! I'm migrating a firmware from the 16F648A to the 16F1847. The problem is that i cant make the comparator work like in the 648A.
I'm just using the comparator 1.
16F648A code:
setup_comparator(A0_A2_A1_A2_OUT_ON_A3_A4);
16F1847 code:
setup_comparator(CP1_C2_A0);
I need to use A2 as positive input, A0 as negative input and A3 as output. I cannot use the wizard because my compiler version doesn't support this pic.
As i read in the datasheet it can be used as i want to. Is that correct?
Anyone can help me?
Compiler version 4.120.
Thanks a lot. |
|
 |
asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
|
|
| Posted: Fri Apr 18, 2014 12:28 pm |
|
|
-post the code that DID work - as a COMPILABLE program
- and ditto for the code that does not.
you don't show enough to know what to do as is-
and
show your old and new SCHEMATIC while you are at it. |
|
|
championx
Joined: 28 Feb 2006
Posts: 151
|
|
| Posted: Fri Apr 18, 2014 12:44 pm |
|
|
Hi ASMBOY thanks for you reply.
I don't have the schematic. The board works fine, the schematic is not the problem. The problem is the configuration of the comparator module.
i cant configure the 16F1847 comparator module to use the A2 input as the positive comparator input, the A0 input as the negative comparator input and the A3 pin as the output of the comparator.
PIN A2 (+) input
PIN A3 comparator output.
PIN A0 (-) input
this is the working code for the 16F648A
| Code: |
#include <16f648A.h>
#fuses HS, NOMCLR, PROTECT, PUT, NOWDT, BROWNOUT, NOLVP
#use delay(clock=20000000)
#use rs232(baud=19200, xmit=PIN_B2, rcv=PIN_B1, stream = RS232, errors)
#use fast_io(A)
#use fast_io(B)
void main(void)
{
set_tris_a (0b00000111); //Ra7-Ra6-Ra5-Ra4-Ra3-Ra2-Ra1-Ra0
set_tris_b (0b00001011); //Rb7-Rb6-Rb5-Rb4-Rb3-Rb2-Rb1-Rb0
fprintf(RS232,"\n\START");
setup_comparator(A0_A2_A1_A2_OUT_ON_A3_A4);
while(TRUE)
{
}
}
|
|
|
|
asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
|
|
| Posted: Fri Apr 18, 2014 12:56 pm |
|
|
what evidence is there that the code you posted ACTUALLY, REALLY WORKS ??
how do you know this is true ??
and how about the new code ?? |
|
|
asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
|
|
| Posted: Fri Apr 18, 2014 1:01 pm |
|
|
and btw:
this compiles in 5.24 also - just fine
now how about that new code and how you define "works" or NOT working - ok ??
ie the way you are testing function ?? |
|
|
championx
Joined: 28 Feb 2006
Posts: 151
|
|
| Posted: Fri Apr 18, 2014 1:17 pm |
|
|
yes it compiles ok and works fine with the 16F648A.
As you may know, the comparator is set to put its output to the A3 pin... so you can test it by putting A2 and A0 to 5v or 0v and see the output on A3 changing.
The code is only to setup the comparator. If i use the 16F1847 the configuration would be the following:
setup_comparator(CP1_C2_A0);
and
| Code: |
#include <16f1847.h> // Selecciona el PIC
#fuses INTRC_IO,NOPROTECT, PUT, NOMCLR, NOWDT, BROWNOUT, NOLVP
#use delay(clock=16000000)
|
Note that i changed the HS fuse to INTRC_IO to use the internal oscillator.
It compile ok, but does not work. The pic initializes ok and put the START string on the UART port... but the comparator doesnt work.
thanks for your help!!! |
|
|
PCM programmer
Joined: 06 Sep 2003
Posts: 21708
|
|
| Posted: Fri Apr 18, 2014 1:58 pm |
|
|
For compiler vs. 5.024, it looks like you should use the following setup:
| Code: | | setup_comparator(CP1_A0_A2 | CP1_OUT_ON_A3); |
I'm not at a location where I can install your version or test it in hardware
at the moment. Maybe I can do that later this evening. Or at least I can
install your version and look closely at the .LST file. But try the above
setup. It may work. |
|
|
championx
Joined: 28 Feb 2006
Posts: 151
|
|
| Posted: Fri Apr 18, 2014 2:15 pm |
|
|
PCM, thanks for your help! it seems that the 16F1847.h file that your version has it is not the same that mine.
That config option is not allowed by my compiler version. |
|
|
PCM programmer
Joined: 06 Sep 2003
Posts: 21708
|
|
| Posted: Sat Apr 19, 2014 2:32 pm |
|
|
The problem is not fixable by simply giving you the setup_comparator()
constants from version 5.024. The setup_comparator() function operates
differently between your version and vs. 5.024.
Instead of spending a lot of time making a work-around macro that
duplicates the function of the modern compiler, I'm just going to post
a setup routine for the specific comparator mode that you want.
The .LST file from the 5.024 compilation of the following line
| Code: | | setup_comparator(CP1_A0_A2 | CP1_OUT_ON_A3); |
was used as a guide for writing the routine shown below:
| Code: |
#include <16F1847.h>
#fuses INTRC_IO, NOWDT
#use delay(clock=4M)
#byte CM1CON1 = getenv("SFR:CM1CON1")
#byte CM1CON0 = getenv("SFR:CM1CON0")
#byte CM2CON1 = getenv("SFR:CM2CON1")
#byte CM2CON0 = getenv("SFR:CM2CON0")
#byte TRISA = getenv("SFR:TRISA")
void setup_comp_CP1_A0_A2_OUT_ON_A3(void)
{
output_drive(PIN_A3);
CM1CON1 = 0x30;
CM1CON0 = 0xA0;
CM2CON1 = 0;
CM2CON0 = 0;
output_float(PIN_A0);
output_float(PIN_A2);
}
//===================================
void main()
{
setup_comp_CP1_A0_A2_OUT_ON_A3();
while(1);
} |
I didn't test this in hardware. It's just a port of the 5.024 routine to
your compiler. If it doesn't work, then let me know and I'll trouble-shoot
it in hardware. |
|
|
|
FAQ 
Search
Register
Profile 
Log in to check your private messages 
Log in
