Anonymous

ZXI standard: Difference between revisions

From Sinclair Wiki
add printer fix
No edit summary
(add printer fix)
Line 7: Line 7:


During the development of the ULAplus replacement ULA, a comprehensive search was carried out to determine a 16-bit port range that clashed with the least devices. An 8-bit port was located that clashed with a single device, the ZX Printer, and a hardware fix created to prevent the ZX Printer using that address.
During the development of the ULAplus replacement ULA, a comprehensive search was carried out to determine a 16-bit port range that clashed with the least devices. An 8-bit port was located that clashed with a single device, the ZX Printer, and a hardware fix created to prevent the ZX Printer using that address.
The following modification to the ZX Printer circuit prevents it being triggered by access to port xx3B.
[[File:Zxprinterfix.png|400px]]


Meanwhile, during the development of the Spectranet ethernet card, a solution was devised to enable multiple devices to page in their own ROMs using 'ripple priority'. The ZXI standard combines these two approaches into a single standard. Legacy devices that do not use ROM paging may also be certified as ZXI compliant on a case by case basis.
Meanwhile, during the development of the Spectranet ethernet card, a solution was devised to enable multiple devices to page in their own ROMs using 'ripple priority'. The ZXI standard combines these two approaches into a single standard. Legacy devices that do not use ROM paging may also be certified as ZXI compliant on a case by case basis.