Interface 1 Replacement ULA

The vLA1 is a pin-for-pin functional replacement for the Sinclair ZX Interface 1 ULA using a modern programmable logic array. The vLA1 provides full support for the Microdrive, RS-232 and Sinclair Network as in the original ULA.

The vLA1 comes in a 40 pin DIL package suitable for soldering into the Interface 1 PCB. A word of caution, however, due to a lack of room within the Interface 1 case, the original ULA will need to be desoldered and the vLA1 installed in its place. There is simply not enough room for a socket. Have a look through the install guide (see the external documentation link elsewhere on this page) and you should get a good idea of what's involved.

The image gallery shows the vLA1 in place on the Interface 1 PCB. Note that the Interface 1 is not included in this offer.

Why did Charlie make it?

The original ULA has an unfortunate history of being prone to spectacularly overheat and fail without warning, leaving an unsightly crater in the Interface 1 plastic case. Because of this, and due to the original ULA now becoming hard to find, the vLA1 project was born.

What makes it special?

The original ULA functionality has been reverse engineered and is replicated in full.