ULA Control Port: Difference between revisions

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When written to, adjusts the border color and audio devices as follows:
When written to, adjusts the border color and audio devices as follows (soft reset = 0):


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Revision as of 00:34, 16 April 2020

Port Number $xxFE
Decimal
Short desc. Controls border color and base Spectrum audio settings.
Bit Mask
Readable No
Writable Yes
Subsystem

When written to, adjusts the border color and audio devices as follows (soft reset = 0):

Bit Function
0-2 Border color
3 MIC output (saving via audio jack)
4 EAR output (connected to internal speaker)
5-7 Unused

Reading the port with certain particular high bytes will read the keyboard - see NextPort:$**FE. Bit 6 of the ULA byte is always the EAR input (signal from tape audio jack - also input from Pi digital audio is now mixed in, since 3.0 cores).