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kgng97ccs
Joined: 02 Apr 2022
Posts: 97
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| Doing a printf for *getenv("bit:xxxx") |
 Posted: Sun Apr 24, 2022 3:25 am |
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I will be using a PIC18LF46K22 MCU, and CCS PCWHD compiler v5.078 within MPLAB IDE v8.92.
I have a "#use RS232" directive and, out of curiosity, wanted to see how the CCS compiler sets some registers, by doing a printf.
I first used this code and was able to print out the settings (TXSTA1 = 0xA4, BAUDCON1 = 0x48, SYNC = 0, BRGH = 1, BRG16 = 1):
| Code: | #include "18LF46K22.h"
#use rs232(UART1, baud=115200, errors, stream=UART1)
#byte TXSTA1=getenv("SFR:TXSTA1")
#byte BAUDCON1=getenv("SFR:BAUDCON1")
#bit SYNC=getenv("bit:SYNC")
#bit BRGH=getenv("bit:BRGH")
#bit BRG16=getenv("bit:BRG16")
void main()
{
...
printf("TXSTA1 = %LX\n", TXSTA1);
printf("BAUDCON1 = %LX\n", BAUDCON1);
printf("SYNC = %u\n", SYNC);
printf("BRGH = %u\n", BRGH);
printf("BRG16 = %u\n", BRG16);
...
} |
I then tried to do the printf without first defining the registers, as follows:
| Code: | #include "18LF46K22.h"
#use rs232(UART1, baud=115200, errors, stream=UART1)
void main()
{
...
printf("TXSTA1 = %LX\n", *getenv("SFR:TXSTA1"));
printf("BAUDCON1 = %LX\n", *getenv("SFR:BAUDCON1"));
printf("SYNC = %u\n", *getenv("bit:SYNC"));
printf("BRGH = %u\n", *getenv("bit:BRGH"));
printf("BRG16 = %u\n", *getenv("bit:BRG16"));
...
} |
The printf for TXSTA1 and BAUDCON1 works fine, but not for the SYNC, BRGH, and BRG16 bits. The compiler says "Expecting a , or )".
How should I write the printf statement for *getenv("bit:xxxx")? |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19536
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| Posted: Sun Apr 24, 2022 3:41 am |
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Do them as you originally did!... 
Problem is that bit definitions are a rather special thing. Getenv for
a byte register, merrily returns the address.. So when you ask for
the 'contents' of this it can be used as a pointer. However a 'bit',
cannot be used as an address.
In your original version it is displaying the value stored inside the
actual bit in the physical register. Not something that can be accessed
as a pointer. |
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kgng97ccs
Joined: 02 Apr 2022
Posts: 97
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| Posted: Mon Apr 25, 2022 8:01 pm |
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| Thank you, Ttelmah, for your advice and explanation. |
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