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Dutch Guy
Joined: 20 Mar 2018
Posts: 21
Location: University of Antwerp
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| Setting up RS-232 with variables from program |
 Posted: Mon Jun 28, 2021 2:22 pm |
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PIC18F8722
CCSC 5.074
Greetings,
I need advice on how to setup a rs232 stream using variables from my program.
I have an initial
| Code: | | #use rs232(baud=MODBUS_SERIAL_BAUD, UART1, bits=8, stop=1, parity=E, stream=MODBUS_SERIAL, errors) |
with the needed defines to work.
Now in my program I have a setup struct that can set and hold baudrates and parity by using a button menu.
Redefining baudrate with #use rs232(baud=x) is provided but HOW do I redefine parity with an int?
Nowhere I can find defines for N,E,U or the string like "EVEN". I tried numbers 0,1,2 and ASCII values for N,E,U
Is it even possible?
Where do I find the code generated by #use RS232 where the parity is implemented? Maybe I can shuffle in a extern variable?
_________________
I just can`t get it all in my head.... But wait, there is a new hole opening up.... |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Re: Setting up RS-232 with variables from program |
| Posted: Mon Jun 28, 2021 5:41 pm |
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| Dutch Guy wrote: |
Where do I find the code generated by #use RS232 where the parity is implemented? |
Look under the #use rs232() statement in the .LST file. You will see
a loop that does XOR's. |
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temtronic
Joined: 01 Jul 2010
Posts: 9238
Location: Greensville,Ontario
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| Posted: Mon Jun 28, 2021 8:16 pm |
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I would think a simple 'switch' function for 3 different 'use rs232(....)' should work ?
something like ...
switch (myparity) {
case(0):#use rs232(.....parity=none...);break;
case(1):#use rs232(....parity=odd...);break;
case(2):#use rs232(.....parity=even...);break;
}
...
where '0' means none,'1'=odd,'2'=even parity (easy for an dinosaur like me to remember...
Jay |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19535
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| Posted: Mon Jun 28, 2021 11:57 pm |
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You cannot use variables for streams.
Key to understand is that a stream actually generates different compiled
code.
However you can (of course), use a variable to select which stream is
actually used.
So for parity:
| Code: |
#use rs232(baud=MODBUS_SERIAL_BAUD, UART1, bits=8, stop=1, parity=E, stream=MODBUS_EVEN, errors)
#use rs232(baud=MODBUS_SERIAL_BAUD, UART1, bits=8, stop=1, parity=O, stream=MODBUS_ODD, errors)
#use rs232(baud=MODBUS_SERIAL_BAUD, UART1, bits=8, stop=1, parity=N, stream=MODBUS_NONE, errors)
#define NONE 0
#define EVEN 2
#define ODD 1
byte Parity=NONE;
void my_putc(char chr)
{
switch(Parity)
{
case NONE:
putc(chr, MODBUS_NONE);
break;
case EVEN:
putc(chr, MODBUS_EVEN);
break;
case ODD:
putc(chr, MODBUS_ODD);
break;
}
}
char my_getc(void)
{
switch(Parity)
{
case NONE:
return getc(MODBUS_NONE));
break;
case EVEN:
return getc(MODBUS_EVEN);
break;
case ODD:
return getc(MODBUS_ODD);
break;
}
}
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Then just use my_putc, and my_getc to put/get the characters, setting
the variable 'Parity' to the value required.
On baud rates, look at the example in the manual entry for
'set_uart_speed', which shows using two bits read from the input
port to change the baud rate. |
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