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djwallace
Joined: 26 Nov 2004
Posts: 10
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| 16F819 Header File Defines for ADC |
 Posted: Fri May 20, 2005 1:02 pm |
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Hello,
I am currently using a 16F88, however, our MPLAB ICD2 was damaged. our old programmers do not support 16F88 so I am trying to switch to 16F819 as they are almost exactly PIN compatable, has a PWM, etc..
My problem occurs when I was looking at the header file to determine the constants to use in setup_adc_ports. They look exactly like those for the 16F877 e.g.:
| Code: |
#define NO_ANALOGS 0x86 // None
#define ALL_ANALOG 0x80 // A0 A1 A2 A3 A5 E0 E1 E2 Ref=Vdd
#define ANALOG_RA3_REF 0x81 // A0 A1 A2 A5 E0 E1 E2 Ref=A3
#define A_ANALOG 0x82 // A0 A1 A2 A3 A5 Ref=Vdd
#define A_ANALOG_RA3_REF 0x83 // A0 A1 A2 A5 Ref=A3
#define RA0_RA1_RA3_ANALOG 0x84 // A0 A1 A3 Ref=Vdd
#define RA0_RA1_ANALOG_RA3_REF 0x85 // A0 A1 Ref=A3
#define ANALOG_RA3_RA2_REF 0x88 // A0 A1 A5 E0 E1 E2 Ref=A2,A3
#define ANALOG_NOT_RE1_RE2 0x89 // A0 A1 A2 A3 A5 E0 Ref=Vdd
#define ANALOG_NOT_RE1_RE2_REF_RA3 0x8A // A0 A1 A2 A5 E0 Ref=A3
#define ANALOG_NOT_RE1_RE2_REF_RA3_RA2 0x8B // A0 A1 A5 E0 Ref=A2,A3
#define A_ANALOG_RA3_RA2_REF 0x8C // A0 A1 A5 Ref=A2,A3
#define RA0_RA1_ANALOG_RA3_RA2_REF 0x8D // A0 A1 Ref=A2,A3
#define RA0_ANALOG 0x8E // A0
#define RA0_ANALOG_RA3_RA2_REF 0x8F // A0 Ref=A2,A3
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Not that the 16F819 only has 4 analog pins. My question is, will these constants still work with the F819? especially considering the F819 doesn't even have a PORT E.
I am using version 3.180 of the CCS Compiler.
Does anyone have any ideas or possibly an updated header file for the 16F819? My other alternative is to set everything manually, but I thought I'd try this as it might be faster to get a solid answer.
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darryl |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri May 20, 2005 1:17 pm |
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You want to use an older version of the compiler for a newer PIC
that it doesn't support.
You need to compare the data sheets. Load both data sheets into
Acrobat and look at the A/D register summary at the end of the A/D
section, and do Tile Horizontal.
What you see, is that the method for setting Analog or Digital pins
is different. The 16F88 uses a bitmask and the 16F819 uses a code.
Basically, you will have to write some (or maybe all) of your own A/D functions.
Also, other built-in CCS functions might not work, and the start-up
initialization code inserted by the compiler will probably not be correct. |
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djwallace
Joined: 26 Nov 2004
Posts: 10
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| hmm.. |
| Posted: Fri May 20, 2005 1:59 pm |
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ok.. that's what I was afraid of..
it's not so much that I'm lazy.. it's just that it has to be done sooner than later.
A friend has used the F819 a little more than myself so I'll get his help..
Thanks.
_________________
darryl |
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djwallace
Joined: 26 Nov 2004
Posts: 10
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| hmm unclear. |
| Posted: Fri May 20, 2005 2:03 pm |
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One more thing,
I'm unclear on your comment about
| Quote: |
You want to use an older version of the compiler for a newer PIC
that it doesn't support.
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My compiler version supports all of the PIC's I mentioned (well except for the ADC features of the 16F819, apparently). I'm not sure what you mean by how I would want to use an older version of the compiler for a newer PIC?
_________________
darryl |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri May 20, 2005 2:40 pm |
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I think I understand your question now. You're wondering if
the A/D constants in the 16F819.H file are correct or if they're
usable in any way, in PCM vs. 3.180.
Obviously all the REx stuff is wrong. There is no Port E on the 16F819.
It looks like CCS just took the definitions for a previous PIC and
stuffed them into the 16F819.H file without really checking them.
This is common when they add support (so to speak) for a new PIC.
It's also common for the A/D functions to be buggy when CCS adds
a new chip.
So the answer is that you should write a test program that uses
all the A/D functions and then carefully check the .LST file against
the data sheet. If they're not correct, you'll have to write your own
functions. |
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