DMI50 Cards and RiscOS 4

Some DMI card users have found that their DMI card will not work once they have installed RiscOS 4 into their machine.

This appears to be a problem with the timing of the RiscOS ROMs interfering with the startup procedures on the DMI ROM. The result is that the computer will not boot up with the DMI card and RiscOS 4 fitted.

When we have tested the problem in our workshop we have not been able to re-create the problem and so it has been difficult to find a solution.

However, thanks to the cooperation of a number of customers we believe we now have a way of geting the DMI card back into action. We cannot guarentee that this will work in every situation but we are optimistic that it will get most systems working again.

The solution involves turning off the process of loading the ROM modules from the DMI ROM as it would appear that it is this process that is causing the problem. RiscOS calls this 'unplugging' the ROM modules.

The problem with doing this is that the normal method is to issue a command to 'unplug' the modules one by one with the DMI card in the machine. However, as the machine is crashing with the card in place this cannot bo done. Instead the modules have to be unplugged using an OS call without the DMI card in place. A simple BASIC program to do this can be downloaded here.
NOTE THAT CARE NEEDS TO BE TAKEN IN DOING THIS AS UNPLUGGING ROM MODULES FOR OTHER EXPANSION CARDS BY MISTAKE COULD CAUSE THE OTHER CARDS TO STOP FUNCTIONING

Once this has been done the DMI card can be fitted into the slot that you specified when running our 'Unplug' program (above). Your computer should now start up OK with the DMI card installed.

For the DMI to function it now needs to have the Modules used by the DMI card loaded in software rather than using the ROM versions as before. The ESP DMI Extend pack does this using the ESP MIDI Support System and will be required to be purchased if you do not already have it.

ESP, 21 Beech Lane, West Hallam, Ilkeston, Derbyshire, DE7 6GP, UK Tel 0115 944 4140 Fax 0115 944 4150 Home email: sales@ESPMusic.co.uk