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| Set_UART_Speed() How does this work ? |
 Posted: Sat Jul 31, 2004 6:33 am |
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At what time does the PCH V3.206 compiler set the BAUDCON register ? I can't find it in the LST file .
#include <18F6621.h>
#use delay(clock=14745600)
.................... Set_UART_Speed(1200);
0CBC: MOVLW BF
0CBE: MOVWF FAF
0CC0: MOVLW 22
0CC2: MOVWF FAC
.................... Set_UART_Speed(2400);
0CC4: MOVLW 5F
0CC6: MOVWF FAF
0CC8: MOVLW 22
0CCA: MOVWF FAC
.................... Set_UART_Speed(4800);
0CCC: MOVLW 2F
0CCE: MOVWF FAF
0CD0: MOVLW 22
0CD2: MOVWF FAC
.................... Set_UART_Speed(9600);
0CD4: MOVLW 17
0CD6: MOVWF FAF
0CD8: MOVLW 22
0CDA: MOVWF FAC
.................... Set_UART_Speed(19200); |
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Ttelmah
Guest
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| Re: Set_UART_Speed() How does this work ? |
| Posted: Sat Jul 31, 2004 6:55 am |
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| Anonymous wrote: | At what time does the PCH V3.206 compiler set the BAUDCON register ? I can't find it in the LST file .
#include <18F6621.h>
#use delay(clock=14745600)
.................... Set_UART_Speed(1200);
0CBC: MOVLW BF
0CBE: MOVWF FAF
0CC0: MOVLW 22
0CC2: MOVWF FAC
.................... Set_UART_Speed(2400);
0CC4: MOVLW 5F
0CC6: MOVWF FAF
0CC8: MOVLW 22
0CCA: MOVWF FAC
.................... Set_UART_Speed(4800);
0CCC: MOVLW 2F
0CCE: MOVWF FAF
0CD0: MOVLW 22
0CD2: MOVWF FAC
.................... Set_UART_Speed(9600);
0CD4: MOVLW 17
0CD6: MOVWF FAF
0CD8: MOVLW 22
0CDA: MOVWF FAC
.................... Set_UART_Speed(19200); |
It doesn't.
The BAUDcon register, is setup as part of the UART initialisation. It is not changed for a different baud rate, so there is no access for the set_uart_speed function.
Best Wishes |
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Guest
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| Re: Set_UART_Speed() How does this work ? |
| Posted: Sat Jul 31, 2004 11:29 am |
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| Ttelmah wrote: | It doesn't.
The BAUDcon register, is setup as part of the UART initialisation. It is not changed for a different baud rate, so there is no access for the set_uart_speed function.
Best Wishes |
That's kind of strange .... the BAUDCON has to be set somewhere....
BAUDCON1 is at address 0XF7E .
I can't find that address anywhere in the LST file.
Are you telling me it happens by magic ? :-)
or is there "stuff" that CCS hides ? I thought the LST included everything . |
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Eric Minbiole
Joined: 10 Jun 2004
Posts: 16
Location: USA
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| Posted: Sat Jul 31, 2004 11:57 am |
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| Quote: | | or is there "stuff" that CCS hides ? I thought the LST included everything . |
Yes, by default, CCS hides the code for a lot of their 'library' functions. Take a look at the #list & #nolist directives. The CCS headers usually turn off listing at the top, and restore it at the bottom. You could remove the #nolist from the top of 18F6621.h, and you'll probably see the BAUDcon register access. |
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Guest
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| Posted: Sat Jul 31, 2004 12:14 pm |
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| Eric Minbiole wrote: | | Quote: | | or is there "stuff" that CCS hides ? I thought the LST included everything . |
Yes, by default, CCS hides the code for a lot of their 'library' functions. Take a look at the #list & #nolist directives. The CCS headers usually turn off listing at the top, and restore it at the bottom. You could remove the #nolist from the top of 18F6621.h, and you'll probably see the BAUDcon register access. |
Yes I got that... but there are no direct ref. to the BAUDCON1 or 2 reg.
Foo.... The Errata sheet mentions a problem with the UART and it would be great to know what is used and how it's setup. |
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Ttelmah
Guest
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| Re: Set_UART_Speed() How does this work ? |
| Posted: Sat Jul 31, 2004 2:37 pm |
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| Anonymous wrote: | | Ttelmah wrote: | It doesn't.
The BAUDcon register, is setup as part of the UART initialisation. It is not changed for a different baud rate, so there is no access for the set_uart_speed function.
Best Wishes |
That's kind of strange .... the BAUDCON has to be set somewhere....
BAUDCON1 is at address 0XF7E .
I can't find that address anywhere in the LST file.
Are you telling me it happens by magic ? :-)
or is there "stuff" that CCS hides ? I thought the LST included everything . |
CCS hides a lot.
Turning off the 'nolist' directive, makes a lot more visible, but you will still see gaps in the code. The easiest thing, s to import it into a package with a disassembler (MPLAB for instance), and search in this. I have had to do this in the past for a couple of such register updates... :-(
It does make debugging a real 'pain' at times.
Best Wishes |
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