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138 bytes added ,  17:08, 9 January 2014
add printer fix
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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.
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The following modification to the ZX Printer circuit prevents it being triggered by access to port xx3B.
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[[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.

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