12F683 Serial Comms

Hi Guys,

A while ago I got code working for my 16F690 that allowed me to communicate back and forth with my PC Serial Port. I Picked up some 12F683's however I am struggling to convert the code to work with the 12F683. The purpose of the project is to provide some sort of Software Protection for a program I have written in vb.net so I figured an 8 pin would be perfect I can even get power off the serial port.

Here is the existing code I have for my 16F690, if anyone has any time to point me in the right direction to use it on a 12F683

Code:

---

Include "modedefs.bas"

DEFINE OSC 4
DEFINE HSER_RCSTA 90h
DEFINE HSER_TXSTA 20h
DEFINE HSER_SPBRG 25
DEFINE HSER_CLROERR 1

ANSEL = 0
ANSELH = 0
CM1CON0 = 0
CM2CON0 = 0

stat VAR byte

stat = " "

Main:
HSERIN [stat]
 if stat = "0" Then goto reqSerial
GOTO Main

reqSerial:
HSEROUT ["51384529"]
GOTO MAin
END

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I am using a max232 with the circuit. I have taken out some of the original code to make it easier to post here, should compile and it works on a 16F690 :)

Thanks,
Ross.

Hi Ross,

The 12F683 does not have a hardware serial port, so you would need to use debugin and debug, or serin and serout, instead of hserin and hserout.

If you need a hardware serial port, then there will be the 12F1822 (pretty soon).

Ah I see. I don't know much hehe I tried to put some code together just to test but it seems not to work. Could this be close?

Code:

---

Include "modedefs.bas"

OSCCON = %01100000 ' Internal 4MHz osc
ADCON0 = 0
CMCON0 = 7
ANSEL = 0
WPU = 0
GPIO = %00000000

rcx var GPIO.4 'input pin
tcx var GPIO.2 'output pin

stat VAR byte

Main:
serin rcx,N2400,STAT
pause 100
 SEROUT tcx,n2400,[stat]
GOTO Main
END

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Looks very close.

If you are still using a rs232, then you want True, if you are not, then just as you did, with inverted.

Ah thanks for pointing that out. I was using a max232 with 'n' and not 't' :P

Working code:

Code:

---

Include "modedefs.bas"

OSCCON = %01100000      'set for 4mhz internal
CMCON0 = 7              'TURN COMPARITORS OFF
ANSEL  = %00000000      'Set A/D OFF
ADCON0 = %00000000      'Analog converter OFF

rcx var GPIO.4 'input pin
tcx var GPIO.1 'output pin

stat VAR byte

Main:
serin rcx,t2400,STAT
pause 100
 SEROUT tcx,t2400,[stat]
GOTO Main
END

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Is a max232 needed? I haven't had much success without it in the past but I might consider trying to lose it since space is a bit tight in the dongle case.

Quote:

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Originally Posted by ross246

Is a max232 needed? I haven't had much success without it in the past but I might consider trying to lose it since space is a bit tight in the dongle case.

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When you use a hardware serial port on a pic16 device, you need an RS232. If you use hardware serial on a PIC18, then you can invert the bits to get away without one.

For degug or serin/out you don't need one. You can follow the directions in the manual for the resistor size to protect your pic.

Awesome thanks so much for your help. Just got to search through the manual now. 10k sticks in my head for some reason but I will check.

Thanks again.

Quote:

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Originally Posted by ross246

Awesome thanks so much for your help. Just got to search through the manual now. 10k sticks in my head for some reason but I will check.

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Not a problem, great to see you got it going.

It's 1K resistor for serout, and 22K (or so) for serin pins.