Re: TNC-PI Checksum error


Steve (KA6PRW)
 

Sorry if this is a double post - but my previous reply appears to have gone into the ether.

Thanks John for your update.  The new version does print PIC version (1), but still pesky checksum error. Always '0xe' from what I am seeing.
           I believe the version of pitnc_get/set that I was using was pointed to by the TNC-PI assembly manual online?
                            I have tried to get the correct versions, so I am not clear what happened there.


Note that when I manually do the xor checksum on the data examples below, I also get a '0xe' as the result:
               8 xor 1 xor 14 xor 40 xor a xor 0 xor 0 xor 0 xor 0 xor 59 = 0xe
               8 xor 1 xor 00 xor 40 xor a xor 0 xor 0 xor 0 xor 0 xor 4d = 0xe

I tried both 'get' and 'set' and through in a reset "15 2", for good luck.
After all these, the checksum error remained. 

EXAMPLE #1 *****************************************

pi@raspberrypi:~ $ ./pitnc_setparams 0 0 1 20

   PIC Software Version           1
01 TXDelay - Zero means use ADC  20
02 Persistance                   64
03 Slottime (in 10 mS)           10
04 TXTail                         0
05 Full Duplex - Not used         0
06 Our Channel (Hex)             00
07 I2C Address (0 = async) Hex   00
   ADC Value                     89
8 1 14 40 a 0 0 0 0 59 c0 sum e
** Checksum Error - Sum = e Should be Zero

EXAMPLE #2 *****************************************

pi@raspberrypi:~ $ ./pitnc_getparams 0 0

Using Serial port /dev/ttyAMA0

   TNC Software Version           1
01 TXDelay - Zero means use ADC   0
02 Persistance                   64
03 Slottime (in 10 mS)           10
04 TXTail                         0
05 Full Duplex - Not used         0
06 Our Channel (Hex)             00
07 I2C Address (0 = async) Hex   00
   ADC Value                     77
8 1 0 40 a 0 0 0 0 4d c0 sum e
** Checksum Error - Sum = e Should be Zero

EXAMPLE #3 *****************************************

pi@raspberrypi:~ $ ./pitnc_setparams 0 0 15 2

pi@raspberrypi:~ $ ./pitnc_getparams 0 0

Using Serial port /dev/ttyAMA0

   TNC Software Version           1
01 TXDelay - Zero means use ADC   0
02 Persistance                   64
03 Slottime (in 10 mS)           10
04 TXTail                         0
05 Full Duplex - Not used         0
06 Our Channel (Hex)             00
07 I2C Address (0 = async) Hex   00
   ADC Value                     77
8 1 0 40 a 0 0 0 0 4d c0 sum e
** Checksum Error - Sum = e Should be Zero

Any suggestions? 
Quite willing to look at code if that might help.  I tried compiling the sources that were in the zip, but I am getting an 'undefined error: FIONBIO'.
               I will continue to look at that.

--
Steve Jones
KA6PRW

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