janbredenbeek wrote:
The Miracle hard disk used the ROM port too and did (of course) work in conjunction with the Trump card
Thank you Jan. I can't understand all the technical details, but you gave me hope
Anyway, if this can help to focus, I'm sure the ROM port (minor?) issue was due only to the achievement of 896K RAM limit.
janbredenbeek wrote:The Miracle hard disk used the ROM port too and did (of course) work in conjunction with the Trump card (it even had a through-connector for extension ROMs).
I haven't understand (yet), how the Miracle HD uses in- and output in an output ROM plug...?
janbredenbeek wrote:The Miracle hard disk used the ROM port too and did (of course) work in conjunction with the Trump card (it even had a through-connector for extension ROMs).
I haven't understand (yet), how the Miracle HD uses in- and output in an output ROM plug...?
In a nutshell, reading specific addresses writes bytes to the peripheral.
QL-SD, for example, reserves an address range of 256 bytes in the upper part of the ROM address range to be able to write bytes to peripherals behind the port. If you read byte address 0 of this range, you transfer a 0, if you read byte address 255, you actually write 255 to the card.