Onboard SPx peripherals

The SPLat expansion framework is designed to handle not only off-board peripherals such as Touch of SPice boards and SPx peripherals, but also onboard peripherals. An onboard peripheral is a peripheral function that is part of the main SPLat board, but programmed as if it were an SPx board. This gives a neat path for advancing from of-the-shelf solutions to full custom designs.

Take the case of a hypothetical external add-on board, a Time of Day Clock (TDC), that uses the SPx bus. This device has a number of registers, and actions commands that are sent to it via the SPx bus. It also has a particular address.

Suppose now that a SPLat customer needs that TDC functionality in a custom controller. He has developed his product using a standard SPLat board, including the standard TDC. What we will do is to build the TDC circuitry onto his custom board, without its own processor, and let the main SPLat processor look after it. For us it is a minimal amount of work to "port" the driver Firmware from a peripheral processor to the main SPLat processor, while for the customer his existing SPLatWare investment is protected and he sees a significant cost saving. The onboard implementation of an SPx peripheral will look exactly the same to the SPLatWare programmer, with the exception of changing from an offboard to an onboard address.

A special case of an onboard SPx peripheral is the LCD port that will be a standard feature of many future standard SPLat board, starting with the MMi99. This port supports an industry standard LCD character display, with size ranges from 2 lines by 16 characters up to 4x20. Although physically located on the board, and having no processor of its own, it uses the same programming as if it were located on a separate board with its own processor.