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koenbielen
Joined: 23 Apr 2009
Posts: 42
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| #use rs232 |
 Posted: Tue Jul 08, 2014 2:37 am |
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Hello
Im having troubles with a analog input and RS232
At startup i put
#use rs232(baud=38400,xmit=pin_b5,rcv=pin_a2,stream=EEPROMPORT)
im doing some checks on this port for 5 seconds.
If no reply is done by receiving a service command I continue the program.
But the pin is never going back to input xmit=pin_b5
even if I place a set_tris_b(0xFF) command.
so how can u undo the
#use rs232(baud=38400,xmit=pin_b5,rcv=pin_a2,stream=EEPROMPORT) |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19535
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| Posted: Tue Jul 08, 2014 3:10 am |
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#USE RS232, on it's own doesn't do anything to stop the chip.
It is a configuration that is used by the functions getc, and putc.
It should be at the top of your file as a configuration. It is not code to use in the program.
Only getc can hang. Read the manual entry for it:
"This function waits for a character to come in over the RS232 RCV pin and returns the character."
Note 'waits'.....
The sequence should be:
| Code: |
#include <18F46K22.h> //chip definition
//ADC setup here if used.
//Now the fuses - depend on your device
#FUSES NOWDT,NOBROWNOUT,NOLVP,NOXINST
//Now the clock
#use delay(crystal=20000000)
//Now the RS232 configuration STREAM name if required
#use rs232(baud=38400,parity=N,UART1,bits=8,,errors)
//You must _always_ use ERRORS with a hardware UART, unless
//you generate your own error handling code.
void main(void)
{
int16 delay_ctr;
char x;
//Now your code.
//If you want to wait for a command, key is that you must _not_
//call 'getc', unless a character is available
for (delay_ctr=0;delay_ctr<50000;delay_ctr++)
{
if (kbhit())
{
//Now there _is_ a character so you can call getc
x=getc();
//and do what you want with the character parse the command
//preferably with a state machine
}
else
delay_us(100));
}
//now, the delay must be shorter than the time between
//characters (260uSec for 38400bps). To avoid characters being missed.
//If no character is available, the delay gets executed, so the unit
//pauses for 100*50000uSec
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Alternatively, you can set it so getc, won't hang (by adding TIMEOUT=xx to the RS232 declaration). Where 'xx' is a time in mSec to wait for a character. However your code then needs to change to test if the returned character is ==0, and RS232_ERRORS==0, to know that a timeout has occurred.
Do a search in the manual, for 'getc_timeout'.
Understand that if you are using gets, this calls getc. |
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koenbielen
Joined: 23 Apr 2009
Posts: 42
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| Posted: Tue Jul 08, 2014 3:29 am |
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Hello
Thanks for fast reply but you misunderstood my post
The problem in have is that my pin is set to output with the
#use rs232(baud=38400.... code
But never can be set again as analog input.
This is a analog input connector and is used at startup to go into service mode via serial commands.
So for a short time i check the pin.
If no command is received i continue the program.
So far so good.
Only thing is that when I further in my code specify the pin to be an analog input --> I will stay output.
Kind Regards |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19535
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| Posted: Tue Jul 08, 2014 3:59 am |
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You need to turn the UART off before the pin can be used for other things.
setup_UART(FALSE);
Tells the compiler to disable the UART. |
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