JR-IDE Rev.B & Rev.C + RPi-Zero Module

Hardware questions and modifications

JR-IDE Rev.B & Rev.C + RPi-Zero Module

Postby alanh » Wed Oct 19, 2016 3:33 pm

So I'm back on the PCJr horse again after a couple year (sorry) hiatus. I had ordered 100x Rev.B boards and 100x connector pairs but soon ran into a problem with mounting the connectors on the PCB as I switched board houses and the holes shrunk. I now believe I'm past that issue. I can now mount connectors perfectly with zero deformation anywhere. So I'm ready to order kit parts, however here is my second problem.. I'm currently unemployed. I'm trying to conserve cash on-hand atm, so it might be a month or two before I can commit to a qty 25 buy.

Rev.B has minor changes over A. I added one extra cap to make sure there is enough bulk capacitance on one end of the board. There isn't a known problem with Rev.A. It's just for good measure. The other change is making the RTC module socket an option: a) install an all-in-one DS12887+ like Rev.A (single module w/ RTC, battery, and XO), or now you have an option b) install a DS12885+ (discrete chip) and mount a separate oscillator and battery holder for CR2032. It would make replacing the battery in 20 years less of a hassle. Everything else is the same. I finally built one up completely today and tested it. Everything works great.

Which brings me to Rev.C - which I'm on the fence about. I'm about to press order now for some prototype extensions modules I described here about 2 years ago. They plug into the JR-IDE and bridge the IDE interface to a Raspberry Pi Zero. There is an FPGA that bridges the two interfaces. The RPi can emulate disk storage from SD card or USB mass storage. It can also accept any USB device supported in Raspbian like USB WiFi dongles. Which means you can a) potentially update the JR image over the air, and b) we can make a packet driver to talk to the Pi and tunnel frames over it's Ethernet stack in bridge mode. I've gone over the design several times, and believe it's sound and very straight forward to develop the needed code once the prototypes arrive.

Which circles back to a Rev.C. I have a Rev.C change that adds three more DIP switches. Like the RTC, they selectively route the three IRQs pins on the side-car bus to the IDE IRQ line. This would be important for a packet driver or NDIS driver to allow asynchronous handling of networking packets. Now there isn't a danger things will overflow. The service daemon running on the RPi could buffer as much network traffic as possible. And older boards can be easily modified to forward networking interrupts by soldering a jumper to your existing boards from the IDE header to the IRQ pin you want. I'm just not sure if this warrants an extra spin or not. Boards are cheap from my supplier atm. About $2.65 per PCB. Interested in other thoughts.

I will order the RPiZ prototypes tonight and hopefully they will be in within a couple weeks.
alanh
 
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Re: JR-IDE Rev.B & Rev.C + RPi-Zero Module

Postby Trixter » Wed Oct 19, 2016 4:25 pm

alanh wrote:I had ordered 100x Rev.B boards and 100x connector pairs but soon ran into a problem with mounting the connectors on the PCB as I switched board houses and the holes shrunk. I now believe I'm past that issue. I can now mount connectors perfectly with zero deformation anywhere.


Is there a trick to doing it that you can pass on?

Interested in other thoughts.


I certainly wouldn't turn away a jrIDE that could talk TCP over wifi, but wouldn't that be large enough as to not fit into a single sidecar?
You're all insane and trying to steal my magic bag!
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Re: JR-IDE Rev.B & Rev.C + RPi-Zero Module

Postby alanh » Wed Oct 19, 2016 6:00 pm

I sacrificed a couple connectors to use on either side of the one I'm mounting in a large vice. The martyr connector can be reused for multiple crimps.

And no, the new module is about 5 x 7 cm with the RPi Zero mounting on top of it. It all fits in a single sidecar enclosure along with a WiFi dongle and adapter (USB A/female to USB A micro/male).
alanh
 
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Re: JR-IDE Rev.B & Rev.C + RPi-Zero Module

Postby James » Thu Oct 20, 2016 5:51 am

As far as the cash situation, I would be willing to put a deposit on one. If some of the other people who have inquired about them would also be willing it might give you some working capital.

The clock with a replaceable battery is appealing and I hope both me and the PCjr are around as when we celebrate it's 50th Birthday.
-PCjr (1989)-DOS 3.3, Racore Drive II, jrIDE-128 MB DOM, jrExcellerator, Tandy Mod, Serial Card, Combo v2, Config Plus, IBM Parallel Port, Megaboard, Xircom PE3-10BT
-PCjr (2001)-DOS 3.3, jrIDE-128 MB DOM, NEC v20, Parallel Port, Comswap, Xircom PE3-10BT
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Re: JR-IDE Rev.B & Rev.C + RPi-Zero Module

Postby KenG » Thu Oct 20, 2016 8:12 am

I would also be willing t put down a deposit if doing so will get me one soon. I have wanted one since I first read about it. The Rev C. additions are interesting, but I would be fairly happy just to get a Rev A or B.
Enhanced PCjr with a jr-IDE (1GB DOM) and a parallel port side car with a compact flash reader and backpack 1.44mb floppy attached. Tandy video mod.
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Re: JR-IDE Rev.B & Rev.C + RPi-Zero Module

Postby Trixter » Thu Oct 20, 2016 9:24 am

I could also put down a deposit.
You're all insane and trying to steal my magic bag!
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Re: JR-IDE Rev.B & Rev.C + RPi-Zero Module

Postby alanh » Thu Oct 20, 2016 11:18 am

Mike had sent me a list of 15 names and I've gotten a few more inquiries beyond that. So I think I'll go ahead and do a run of 25 Rev.B boards I already have here. In order to save some cost, I'm going to order the main PLDs from eBay/China. It saves $8 per chip. So it might be a couple weeks for the slow boat to arrive. I'll order some extra PLDs so that I can do a different break-down if you don't want the entire parts kits.

The economics are what they are. The connectors are not cheap and you will still need to supply your own side-car shell and DoM.

PCB + mounted connector only = $20
PCB, mounted connector, pre-programmed CPLDs and flash = $30
PCB, mounted connector, full parts kit / unassembled = $70
PCB, mounted connector, full parts kit / assembled & tested = $100

All prices include small flat-rate box shipping to anywhere in the US. I can do international shipping on a per request basis. Full disclosure, the first two options are purely at parts cost. The full un-assembled kit includes $10 to me. The assembled kit includes $40 to me. Both full parts kit options include pre-programmed parts. I'll likely the 4th option on eBay for more than the above price.

I've used 2GB versions of this DoM in the past, however I cannot personally vouch for the 4GB or this seller:

http://www.ebay.com/itm/Industrial-Disk ... xyeglTaNlv

I'll let people know with a mass-email when everything has arrived and I'm ready to full-fill orders.
alanh
 
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Re: JR-IDE Rev.B & Rev.C + RPi-Zero Module

Postby Trixter » Thu Oct 20, 2016 11:44 am

Your dedication, skill, and transparency is refreshing. (Better than the typical kickstarter!)
You're all insane and trying to steal my magic bag!
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Re: JR-IDE Rev.B & Rev.C + RPi-Zero Module

Postby KenG » Thu Oct 20, 2016 4:09 pm

The pricing seems very fair. I was planned on using a laptop hard drive. I have a few laying around from when I used to rebuild laptop computers. What additional hardware would I need? I thought the board could supply that level of power and I might just need a 3.5 to 2.5 ide adapter.
Enhanced PCjr with a jr-IDE (1GB DOM) and a parallel port side car with a compact flash reader and backpack 1.44mb floppy attached. Tandy video mod.
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Re: JR-IDE Rev.B & Rev.C + RPi-Zero Module

Postby alanh » Thu Oct 20, 2016 5:15 pm

There is a 2 pin header where you can solder wires or matting .1" connector to provide HD power. Laptop HD should work.
alanh
 
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