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pfournier
Joined: 30 Sep 2003
Posts: 89
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| #use rs232(...enable=PIN_J7...) |
 Posted: Tue Mar 21, 2006 11:37 am |
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I am using PCWH 3.245 with an 18LF8622.
I used the following line in my code:
| Code: |
#use rs232(baud=ARINC_BAUD, xmit=PIN_G1, rcv=PIN_G2, ERRORS, parity=O, bits=8, enable=PIN_J7)
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J7 never seems to go high when I transmit.
I put in code to deliberately toggle it just to prove that I could do it and that works fine.
I see the serial data coming out of the G1, so I know the serial port is working.
Is there something I don't know?
_________________
-Pete |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Mar 21, 2006 12:56 pm |
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Port J is configured for use with the External Memory Interface upon
power-up reset. CCS doesn't change it to digital i/o for you.
You need to do it with a line of code.
See this thread for an example:
http://www.ccsinfo.com/forum/viewtopic.php?t=23622 |
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pfournier
Joined: 30 Sep 2003
Posts: 89
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| Posted: Tue Mar 21, 2006 1:14 pm |
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I did that already. Note the place where I said:
| Quote: |
I put in code to deliberately toggle it just to prove that I could do it and that works fine.
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_________________
-Pete |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Mar 21, 2006 1:55 pm |
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I made the test program shown below and looked at the .LST file.
The generated code looks OK. This was with PCH vs. 3.245.
| Code: |
#include <18F8622.H>
#fuses XT, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_G1, rcv=PIN_G2, ERRORS, parity=O, bits=8, enable=PIN_J7)
#byte MEMCON = 0xF9C
#bit EBDIS = MEMCON.7
//==========================
void main()
{
EBDIS = 1; // Port J = digital i/o
while(1)
{
putc(0x55);
delay_ms(1);
}
} |
See the code below. It appears to toggle the Enable pin
high and low properly.
| Code: |
... #use rs232(baud=9600, xmit=PIN_G1, rcv=PIN_G2,
ERRORS, parity=O, bits=8, enable=PIN_J7)
00004: BCF F9A.7 // TRISJ.7 = output
00006: BSF F91.7 // LATJ.7 = 1 (set enable high)
00008: MOVLW 08 // Calculate odd parity
0000A: MOVWF 01
0000C: CLRF 07
0000E: INCF 07,F
00010: MOVFF 06,00
00014: MOVF 00,W
00016: XORWF 07,F
00018: RRCF 00,F
0001A: DECFSZ 01,F
0001C: BRA 0014
0001E: BTFSS FA4.4 // Wait until transmitter is ready
00020: BRA 001E
00022: MOVLW FE // Set TX9D bit = odd parity
00024: ANDWF F6C,F
00026: BTFSC 07.0
00028: BSF F6C.0
0002A: MOVFF 06,F6D // Put byte into transmitter
0002E: NOP
00030: BCF F9A.7 // TRISJ.7 = output
00032: BSF F91.7 // LATJ.7 = 1 (Set enable high)
00034: BTFSS F6C.1 // Wait until byte is transmitted
00036: BRA 0034
00038: BCF F9A.7 // TRISJ.7 = output
0003A: BCF F91.7 // LATJ.7 = 0 (Set enable low)
0003C: GOTO 009A (RETURN)
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pfournier
Joined: 30 Sep 2003
Posts: 89
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| Posted: Tue Mar 21, 2006 3:17 pm |
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This looks interesting, you've shown me where to look for this. I'll be back
_________________
-Pete |
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pfournier
Joined: 30 Sep 2003
Posts: 89
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| Posted: Tue Mar 21, 2006 4:36 pm |
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Ok,
I figured it out.
The setting and resetting of the enable line is done within the putc().
I thought it was done at a MUCH lower level.
I handle the transmitting in an interrupt with a fairly large circular buffer so I will fill the buffer turn on the enable line and leave it on until the buffer is empty.
Interestingly I just realized as I looked at the code that parity is also calculated in the putc and is not done in hardware....looks like I have to do that myself!
Thanks for the insight!
_________________
-Pete |
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