Thanks for this Brian, I didn’t even think there was a Teensy version already. I’ve reverted my base code to this version and seems to catch packets better. Question though, is there a specific reason why it runs @ 2mhz on the Teensy?
Bill Nobel b_no...@hotmail.com<mailto:b_no...@hotmail.com> On Sep 20, 2019, at 9:06 AM, Brian White <bw.al...@gmail.com<mailto:bw.al...@gmail.com>> wrote: I don't remember any checksum problems with directories with this code on teensy 3.6 https://github.com/aljex/SD2TPDD/tree/bkw_teensy36 It's not a complete implementation though so I would be interested in a good solid re-do. Note specifically the bkw-teensy36 branch, not master. Master is Jimmy Petit's original that I forked from. But I was reading and writing files and using sub dirs and getting good listings in ts-dos etc. On Fri, Sep 20, 2019, 5:36 AM Bill Nobel <b_no...@hotmail.com<mailto:b_no...@hotmail.com>> wrote: I should also note an observation I’ve had with my code. I’m going from the Teensy to a Max3232 to the T-102. Even with power off on the 102 I receive garbage on the port. My code seems to catch all the preambles though to start a packet. Code is starting to get larger so I’m going to post a Github for anybody to look at. Bill Sent from my iPhone > On Sep 19, 2019, at 10:17 PM, Bill Nobel > <b_no...@hotmail.com<mailto:b_no...@hotmail.com>> wrote: > > Hi John, yes I receive 2 packets fine (with response) then things go strange > only on checksum. Your C# routine is different from DLPlus for the Calc, > I’ll try that in the morning and see if that changes. > > Sent from my iPhone > >> On Sep 19, 2019, at 9:58 PM, John R. Hogerhuis >> <jho...@pobox.com<mailto:jho...@pobox.com>> wrote: >> >> Are you sure you got a full, aligned packet? It starts with ZZ , counted >> length, no missing characters? >> >> The DLPlus checksum is correct. More likely you're misaligned, or somehow >> dropped, swapped, or corrupted a character. >> >> Here is the C# code too for comparison >> >> public byte Checksum(byte[] ary, uint ofs, uint fence) >> { >> uint sum = 0; >> >> for (var i = ofs; i < fence; i++) >> sum += ary[i]; >> >> return (byte)((~sum) & 0xff); >> } >> >> Welcome to the cabal of TPDD protocol initiates. >> >> -- John.
