I have done some more investigation into the possibility of port ELKS to run
on the Psion.
I have had the following successes:
1). Compiling and running code built on Linux to control the IN and OUT
instructions without causing a Memory Protection Faults.
2). Using Psion Serial Cable ('soap on a rope') to transmit from Psion at
9600 baud, there's a problem with reception as I'm not attempting to use the
interrupts and 'received' flag isn't working - I'm working on it. This gives
us enough to see what's happen when we try and load the kernel.
3). The Page Select Registers read at 0x06, 0x07, 0xF8, 0xF9 respectively. I
now think that they are selecting full 64k pages and are configured like
this in a user task to give the maximum 'flat' memory size. I think they
might change when the system is accessing the RAM disk.
Things to do next:
1). Write to the LCD screen memory. Does anyone know whether this has a
'character' port as well as the 'bitmap' one?
2). Read the Keyboard.
3). Confirm uses of SSD's via ASIC4.
4). Probe Page Selects further to find out if there is any overlap and how
we might control them. This might make memory mapping awkward.
I have posted more information (plus example code) on my website:
http://www.mungewell.ndirect.co.uk
Simon Wood
Hardware Engineer
Pace Micro Technology plc
Victoria Road, Saltaire, Shipley
West Yorkshire, BD18 3LF
Tel : +44(0)1274 532000 Fax: +44(0)1274 532029
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