On 9/21/19 4:46 PM, Bill Nobel wrote:
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?
With TeensyDuino installed you can specify whatever mhz you want to run
the cpu at in the Android ide.
I remember manually selecting different speeds to find the lowest speed
that still worked, to reduce power draw.
With low cpu speed and adding hardware interrupt wake/sleep calls to the
code, I managed to get down to 3.5ma or so while idle, depending on the
sd card. Different brands of sd card have big differences in power draw
even while idle. I got the sleep and initial power-on behavior working
better after this video, and that's where that github currently sits.
It's not *great*. I don't present it as feature complete and thoroughly
tested. It's tested about as far as that video.
I didn't think the ide choice was recorded in the .ino file or anywhere
else within the repo, just local user settings, but maybe it is.
Because, see this comment:
// Debug console - where shall all console messages go?
// Teensy can not use Serial (usb) below 24mhz
// But can do the the TPDD job all the way down to 2mhz, which uses the
least power.
// Usually "Serial" or undefined, but could add oled etc for output-only
display
// If undefined:
// * All Serial (built-in usb) code is #ifdeffed out so it isn't in
the microcontroller at all
// * Cpu can be underclocked all the way down to 2mhz
//#define CONS Serial
#undef CONS
I found that the tpdd functions worked at 2mhz, but I needed 24mhz to
use the built-in serial-over-usb console. I set the code to default to
no console, which *allows* you to run as low as 2mhz, but I didn't think
it was actually somehow specifying 2mhz by recording that in a file
somewhere, except possibly some local user config file.
Teensy has audio hardware so I was thinking ultimately it should be able
to both play and record cassette files and save them as files. And there
is an rtc so it should be possible to make a small basic app that reads
a fake/virtual file via tpdd protocol. The file wouldn't exist, merely
the tpdd server would recognize a magic filename and send back the
current date/time from the rtc in place of a file from the filesystem.
And of course a dos-injector. dlplus already has something to do that,
which I have not yet actually gotten to work, however it does look
pretty straightforward and no reason it shouldn't work and looks simple
to clone in sd2tpdd (or PDDuino as I've apparently called a local copy
on my laptop). I've mostly just used the separate teensy installer app
that comes in the dlplus zip file because it works. I think the best
would be to duplicate the tpdd2 bootstrap procedure. That works very
well and requires very little of the user when starting from scratch
with as fresh cold-reset M100. But that's at least partly harware
dependent. The tpdd2 can tell if the m100 is "listening" or not at
power-on, and decides based on that whether to just squirt out the IPL
basic code even though it didn't receive any commands. I think it should
be possible to replicate that on teensy. It might require actually
hooking up more of the serial control lines so the teensy can read the
state of dtr/dsr or something.
Anyway, I did manually compile my copy to run at 2mhz, via Tools->CPU
Speed, but I would have thought if you just took the code and compiled
it, it would use the default 180mhz for Teensy 3.6.
And the way the code is configured as it sits on github, it can be run
at 2mhz because the built-in usb-serial console is disabled.
https://www.youtube.com/watch?v=_lFqsHAlLyg
--
bkw
Bill Nobel
[email protected] <mailto:[email protected]>
On Sep 20, 2019, at 9:06 AM, Brian White <[email protected]
<mailto:[email protected]>> 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 <[email protected]
<mailto:[email protected]>> 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 <[email protected]
<mailto:[email protected]>> 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
<[email protected] <mailto:[email protected]>> 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.
