In [part one of this series] I outlined the functionality of the Omni 128HQ Desktop from [retro-radionics], In this post I’m going to discuss how to configure the Omni via DIP switches.
The DIP (Dual Inline Package, should you care) switches are located on the right hand side of the Omni. The defaults that came with my Omni are shown below.
The switches are divided into sections by function. The following diagram shows the default switch configuration that my Omni shipped with.
Switches are either on (up position) or off (down position), in the preceding example all switches are on except switch 5.
There are three banks of switches:
- 1, 2, 3: Hardware settings (purple area)
- 4, 5: divMMC configuration (cyan area)
- 6, 7, 8: Rom Selection (green area)
Not all switches in all combinations necessarily have meaning.
The switches themselves are very small and you will need to use a tool to set them. The perfect tool for the job is the humble cocktail stick. Don’t use sharp objects as they may damage the switches.
The official FAQ for the Omni is available on the [ZX omni Facebook page] (You’ll have to apply for membership, I don’t think it’ll be refused!)
The DIP Switch settings outlined there formed the basis of this text, but I found that the implementation of the Omni differs from the description posted there.
The first switch bank (purple) has three switches (1, 2, 3) that control the hardware configuration.
|1||On enables divMMC system support, off disables it.|
|2||On allows the divMMC firmware to be flashed, off means read-only|
|3||On enables Kempston joystick support|
Several of the ROMs that are supported require divMMC support to be disabled as they conflict.
The second (cyan) bank of switches specify the of firmware supported by divMMC. There are two switches and so 4 options.
|00 - Enable UnoDOS 3 support|
|01 - Enable UnoDOS 3 support|
|10 - Enable esxDOS 0.8.6 support. This is one area where my switches a flat out different to the ones mentioned in the FAQ, the FAQ has the two divMMC switch settings the wrong way round for my setup..|
| 11 - Enable esxDOS 0.8.5 support see above
I expect the meanings of these switches to change over time as different versions of firmware are released.
## ROM selection switches
The final bank of three switches (green) configure what ROM is being used for the emulation. Three switches give us 8 combinations, all of which are used.