ULA Control Port

From SpecNext official Wiki
Revision as of 15:53, 29 August 2017 by wiki>Hyphz
Jump to: navigation, search
Number $xxFE
Decimal
Short desc. Controls border color and base Spectrum audio settings.
Bit Mask %---- ---- ---- ---0
Readable No
Writable Yes
Subsystem

When written to, adjusts the border color and audio devices as follows:

Bit Function
0-2 Border color
3 Enable MIC output
4 Enable EAR output
5-7 Unused

Reading the port with certain particular high bytes will read the keyboard (see Keyboard ($**FE / 254). Bit 6 of the ULA byte is always the EAR input.