After many months of preparation, JiffyDOS production ROM overlays are finally ready for distribution. The system utilizes the ROM-el FLASH-based ROM emulator, allowing the units to be fully assembled before programming. Units should be available shortly for sale in the online store. Click on the picture for a larger view.
Based on a customer request, I’ve designed a small adapter card that will allow C64 cartridges to be used in the Commodore VIC-20. The design is not finished, and suggestions are appreciated. Switches allow the IO and BLK select lines to be configured per cartridge. Barring any major changes to the design, I hope to have units available early 2010.
I tried a few, but decided this one was simple enough to meet my needs, yet flexible enough for the items I have to sell. I hope to add my full inventory over the next few weeks.
Aries was backordered on the required 24 and 28 pin headers needed to finish testing, and the order just came in this past week. Thus, I finally had a chance to solder and test the units. Testing went well, and I can program the units with my Willem programmer. Originally designed to hold a 29EE512 64kB EEPROM, I found a good price on Atmel AT49F001 128kB 5V Flash, so I made the necessary adjustments and tested with the new memory. Testing went well, so I am releasing the design to production.
I have noticed one issue that I need to address. Some CBM units have an RFI shield that doubles as a heat shield. To perform the latter function, metal “fingers are stamped out of the shield that press on the top of the ICs. I need to ensure the metal shield/heat sink does not contact any of the pins on this unit.
The PCB house shipped the first two ROM-el boards for inspection and testing. Once they are assembled and testing, I will release the design to production.
As one can see, the PCB is a merged set of 4 designs. The tabs between the designs are designed to be broken, separating the individual units after assembly.
I’ve initiated phase 1 of ROM-el production, scheduling the PCB design for production and shipment. ROM-el will be completed in 3 phases:
- PCB manufacture and shipment of 2 bare boards
- Manual assembly and testing
- Release PCB for assembly and shipment
This is typical for new designs, for the following reasons:
- Given the low cost of production boards, it’s cheaper to make a production board run instead of an initial prototype board run. In the best case, the board is operational and no prototype board costs are incurred. At worst, the board must be “spun” once more, but the total cost does not exceed a prototype + production run cost.
- Shipping 2 boards ahead of time permits verification of the design before assembly. The boards are shipped at no cost by “piggybacking” them on a previous order that is nearing completion.
Normal turnaround is 10 business days (2 calendar weeks), so I expect boards around July 12th.
To save costs in creating the SMT stencil and the boards themselves, I “merged” 4 designs into one set of files for the PCB house using Gerbmerge. I struggled to install the program in Windows, which was unsucessful. The application has some dependencies, one of which requires a C compiler. The Windows install of the dependency assumes Visual C++, which I do not own. After wasting a few hours, I installed on the local Linux server, which was trivial. The application is very straightforward, and I was able to create a minimal merged set of files in a few minutes. Thus, I will be receiving 100 units of:
- ROM-el 2364
- ROM-el 23128/23256
- 2364Adapter (simple DIP style 24-28 pin adapter
- 6540Adapter (CBM-Hackers folks asked for this design, which has not been tested)
The remainder of the 64NIC+ boards have shipped to CCCC for sales and distribution. The 1.0a board sillkscreen looks very professional and calls out not only the Cincinnatti club but also Eric Pratt and Till Harbaum, whose designs I utilized in creating 64NIC+.
The first 20 boards have belatedly arrived from the assembly house. Scheduled to arrive for the C4 EXPO, they were delayed and then sent to my work address instead of the EXPO location.
I am busy making the required minor modification to the 1.0 PCB layout to address issues found during initial testing. These 20 initial boards (+ the 2 prototypes) will be special editions, as the remainder (80) of the units will sport the 1.0a PCB design, which corrects the minor issue with the board. It will be easy to spot a 1.0 board, as much of the silkscreen artwork is missing (an error on my part in creating the files for the PCB house). Still, both the 1.0 and 1.0a boards will function the same.
23128 and 23256 ROMs are not as hard to deal with, as 27XXX JEDEC standard EPROMs share the same pinout. However, some of the benefits of the 2364 ROM-el still remain, such as:
- Use of 5V programmable FLASH/EEPROM
- Can be pre-assembled and field programmed
If used in a switched ROM scenario (one where the upper address bits are toggled on or off via a switch), this design can save a lot of time (most 27256/27512 switched ROM replacement options I’ve seen manually bend the additional address pins over the top of the EPROM and hand solder a resistor to Vcc.)
Thus, I’m considering this unit as well for production. It offers some additional configuration options over the 2364 ROM-el, but retains the ease of assembly and programming of the 2364 ROM-el.
Another project of mine requires a way to replace the 2364 ROMs on Commodore computers, so I started looking for a 2764 to 2364 adapter. After designing one, I determined that DIP EPROMs are starting to get very expensive, so I set about designing a Flash version. My tentative name is ROM-el. Since Flash is considered ROM as well, the name is a bit off, but I liked it, and only the pedantic will probably care.