64NIC+ Initial Boards Arrive

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.

23256 ROM-el

23256 ROM-el PCB
23256 ROM-el PCB

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.

ROM-el ROM Eliminator

ROM-el ROM Eliminator
ROM-el ROM Eliminator

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.

64NIC+ Out for Production

64NIC+ top view
64NIC+ top view

2 64NIC+ boards arrived on April 20, and I assembled one in the evening. Initial testing with Devia’s NIC-Test was unsuccessful, so I gave up for the night. After work on the 21st, I pored over the schematics and determined I had miscopied a resistor layout from Eric Pratt’s 64NIC design. The resistor must be tied to ground, not Vcc. Dubious that such a small change would make the board work, I nonetheless made the change and …. it did nothing.

I decided I’d ruined one board, so I assembled the second board, taking care to make the resistor mod before plugging it in. Devia’s NIC-Test worked immediately. Later, I tried the apparently ruined board and it also worked, so it appears I did not completely ruin the board.

Given the success, I immediately released the board to production that evening.