Mike's PCjr Page

I've recently been playing with my original (Alan design) JR-IDE on two working systems I use.

The original setup was JR-IDE plugged into Jr case, then Par.Port side car on the outside..
This setup has worked good for months...

I pulled off the two side cars and reinstalled, different order with diff. results.
DOS 5 Installed, boot system.FYI

Slot 1 = first side car on the Jr
Slot 2 = Second side car attached to first side car ( outter most sidecar or last installed.)

A) JRIDE - SLOT 1 . Par.Port Side Car - SLOT 2
1) JRIDE w/DOM (DOM gets power from JRIDE brd pin 20) system boots OK
2) JRIDE w/2.5" (HD Gets power from JRIDE 5V BrdJumper) Samsung HD (known good) system boots OK
3) JRIDE w/2.5" (HD Gets power from External Connection to JR power Y-Cable from Floppy Drive) Samsung HD (known good) system boots OK
4) Installed a Third Par.Port sidecar (third position, outmost sidecar) system boots good for all 1 & 2 & 3 setups boots OK

B) ParPort SideCar - SLOT 1 JRIDE - SLOT2
1) JRIDE w/DOM (DOM gets power from JRIDE brd pin 20) system boots BAD (note: system counts mem, sees DOM , ESC, Press DOM to boot, System Hangs)
2) JRIDE w/2.5" (HD Gets power from JRIDE 5V BrdJumper) Samsung HD (known good) system boots BAD
(note: system counts mem, sees HD , ESC, Press HD to boot, System Hangs)
3) JRIDE w/2.5" (HD Gets power from External Connection to JR power Y-Cable from Floppy Drive) Samsung HD (known good) system boots BAD
(note: system counts mem, sees HD , ESC, Press HD to boot, System Hangs)

Did not see the need to test with SLOT3 Par.Port Card.

Note: I tried 3 different Par.Port Side cars to eliminate the idea I had a unique (bad) Par.Port side car, made no difference, all three in SLOT 1 produced
a system Hang results.

Also tried this on Two different Jr Systems, same results.

Determined that Power from JRIDE board jumper or External power made no difference, especially with the HD attached, as it is listed the HD needing .7A @5V
I was a bit concerned about the current loading, but this seemed to be ok getting power from the JRIDE Aux power jumper.

Suspect that the JRIDE add-on is sensitive to the JR BUSS breakout on the JR.side connector.
seems the buss may be getting loaded down when SLOT 1 is the Par.Port car and JRIDE is SLOT2.
I am not convinced that a simple increase of connector from the ParPor sidecar would cause signal degradation.
Possible noisy signals due to the ParPort in SLOT1, but I have not put a scope on the system yet, As I was hoping to get Mike and Alan's
initial testing of the JRIDE results when the design was being debugged before I delve in too deep.

I would be interested in other results from JRIDE users to know if different results with different sidecars, Speech car, or others
had Fail results by putting the JRIDE on the Out most Sidecar position.


WHY: I did this testing as I have re-spun Alans JRIDE and have boards coming in to test,
I also designed a 3D printed side car that would be a plug and Play and hold a 2.5" HD , fan, LED indicator on front of sidecar.
I put My original JRIDE (Alans design) into the case, with a few mods to the case, and this is when I discovered it would not work when installed
in SLOT2 position, SLOT1 position, had no issues, Boot was OK

So I need to find an answer to this as the 3D printed sidecar is wider and would not allow a Sidecar attached to it as the JR conn sits too far inside to mate to due to
the extra wide case for the HD inside and fan.
NOTE: NO Fan was connected during the above testing.
This is a nice Plug n Play solution for the JRIDE, but does not seem to work in any position other then SLOT1.

Any one else have any experimental results with POSITION of the JRIDE being attached ?

Chuck

Just a side note here ...

Also wanted to add, after contemplating this a bit more, I have had some issues with the JRIDE SLOT1 and ParPort sidecar in SLOT2
where my ZIP Drive would not find the ParPort at boot up. Using LPT_test also showed the ParPort was not active.
Re-boot would usually fix this issue...
This issue was also on two systems with similar results, so there may be some drive issues with the original Jr Line drivers.

I am thinking maybe using some Passive PullUp/PullDown resistors, or even an Active line termination as part of the testing for a solution..

Update:
Went to McDonalds for breakfast, and sittin there was Thinking about the bus loading and possible signal issues with multiple sidecars,
so I decided to try another experiment.

SLOT 1 - Parallel sidecar
SLOT 2 - JRIDE
SLOT 3 - Another Parallel Side car

I did this to possibly determine if the JRIDE card would boot due to possibly loading the Signals by putting another sidecar in the outtermost position.
So the JRIDE is sandwiched inbetween the two ParPort side cars.

Power to the system and just let the JRIDE Bios walk thru and boot up Booted up OK
did this about 5 times with ALT CTRL DEL reboot and it would boot up fine each time.....This is good news...

Also wanted to be sure that using the Keyboard and pressing ESC then select the Hard drive also worked, this Too was OK

I then removed the otter ParPort side car and the JRIDE was once again the outter most card with ParPor in SLOT 1, and the BOOT FAILED..

So I am fairly confident that the JRIDE , when in the outter most side car position is needing some loading on the Address/Data etc signal to maybe clean them up.

I have some termination resistor packs on order and will provide some external termination on the open side of the JRIDE connector to see what the results will be.
I will try to isolate the Address /Data /and other signal control lines to see if there is a particular set of signal that are being affected.

More to come, but I think the termination will be the answer.

For those greyhaired users, this is a solution used on the old school S-100 bus design where you could have 10+ cards installed and the mother board bus lines used Pull-up/Pull-down to help the signal transition times due to individual signal line loading,. the pull up/ pull down would help the signal sit at midpoint and then helped with the rise and fall times with cleaner signal transitions.

Trivia
My S-100 system back in the 70's had 7 cards, 3 8K memory Goudbout boards, serial card, Processor card, Northstar Floppy controller (hard sectored) and video card.
lots of power... the power supply was from SUN a chinese supplier, and the 5V was rated at 25A, it weighed 25 lbs. No switcher, just transformer(big) with large diodes and Huge Caps... the good old days... ps I handbuilt and soldered every card from kits... that is another story...

chuck

Update:
After using some termination resistors on the DATA 0-7 lines the JR-IDE Board has started booting ok in SLOT2.

I will stick a scope on this tonight and take a look at that Before and after signal with the termination and without...

I've updated my PCB to include the Termination in the next spin board. but I'm fairly confident that this is a must
to have and will help any of the side cars added as well.

A quick look at the board layout...
(you may need to zoom out if the board does not show fully)

but I've added a few changes,
Added the 2MM IDE connector for the the 2.5" HD's, as I have made a 3D printed case for a Plug n Play solution.
I plan on using straight headers for Cabling, but also if the folks want to use a DOM then a Right Angle can be use.
I had issues with my DOM and switched over to my 2.5" HD and it seems so much faster and quicker to boot....
but the FAT tables seemed to get corrupted when I used PCTOOLS and tried rearranging the File structures for display...

My version, is not hobby friendly, ie. you build it, but I think most folks prefer getting a 'working and tested' unit anyway so I decided to use SMT parts.
I also added a slot for a 40mm x 40mm fan on the back side it plugs into the 12V AUX on the bottom of the board.
Also a jumper for (top right) for the 2.5"HD power to get this from the JR 5V so you do not need external power.
I also have a spot on the back side of the 3D printed case that would allow for a 'walwart' 5V 1A if needed to provide power to the Drive.
On the front is a hole for the HD LED..

Still waiting on boards to come in then I will build up a couple and test them out...
but this will hopefully be another path for the Folks that want this add-on, and thanks to Alan for the sharing of his hard work
and ( if he looks close) at the top silkscreen is his 'hawk' I think it is a hawk...correct me if wrong..

here is a final closeout for this thread...

referring to the two screen shots below Before and After: ( Without the Termination resistors and With them )
Using a 390ohm Pullup and 470ohm Pull down (resistor divider type circuit)
we are looking at (1) of the data lines D0 on the JR Bus. I did look at a couple signals D0,D1,D2 and all were mostly the same results.
this signal was caught during a BOOT to the JRIDE.

When I get the JRIDE boards in and build one I will actually stick my logic analyzer on and scope to get a good picture
of how the RevC board signals will look, especially with regards to the IOW/IOR trigger and ampiltude.

WITHOUT :
you can see that with the JRIDE in SLOT2 (outter position, attached to the par.port sidecar)
the signals are somewhat clean but do suffer from amplitude, as they are barely hitting the 4V levels on these typically 5V transition swing.
the bottom level has a bit of a glitch on the end just before transition to HIGH level, but this is not gonna be an issue as the signals are usually
clocked in at the front end. and the transition to HIGH looks good a little ringing on the top side but nothing that is not normal.
the boot up from the JRIDE was BAD,,, did not boot just hung at the ESC prompt.

WITH :
the signals have cleaned up but you can see that with the 'voltage divider' termination scheme we now see a 'tri-state' type signal
this provides a couple of items that help the signal integrity.
because the signals now try to sit around the mid level 2.5V level, the transition to HI and LO are aided with quicker rise and fall times.
Also showing you can see the High level now is a little better, not yet to the 5V level but sufficient.
Noted also that the entire signal is sitting abit higher, ie. the low end is just off the bottom but for TTL this is ok under about .8V.
System booted to hard Drive and DOS Loaded OK, did a few CHKDSK and no issues.

So the termination of the Data Lines gave the JRIDE a bit more reliability on when used with other sidecars.
Note this was some very preliminary testing as time allowed me to delve into this.. I would also like to review
testing with just PULLUP and review those results... (when my JRIDE Rev C board arrive)