Difference between revisions of "ULA Control Port"

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{{Port
 
{{Port
 
|Number=$xxFE
 
|Number=$xxFE
 +
|NumberDec=254
 
|ShortDesc=Controls border color and base Spectrum audio settings.
 
|ShortDesc=Controls border color and base Spectrum audio settings.
|PortMask=%---- ---- ---- ---0
 
 
|Readable=No
 
|Readable=No
 
|Writable=Yes
 
|Writable=Yes
 
}}
 
}}
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):
  
 
{| class="wikitable"
 
{| class="wikitable"
Line 13: Line 13:
 
| 0-2 || Border color
 
| 0-2 || Border color
 
|-
 
|-
| 3 || Enable MIC output
+
| 3 || MIC output (saving via audio jack)
 
|-
 
|-
| 4 || Enable EAR output
+
| 4 || EAR output (connected to internal speaker)
 
|-
 
|-
 
| 5-7 || Unused
 
| 5-7 || Unused
 
|}
 
|}
  
Reading the port with certain particular high bytes will read the keyboard (see {{PortRef:$**FE}}. Bit 6 of the ULA byte is always the EAR input.
+
---------
 +
 
 +
Reading the port with certain particular high bytes will read the keyboard - see {{PortNo|$**FE}}. Bit 6 of the ULA byte is always the EAR input (signal from tape audio jack - also input from [https://wiki.specnext.dev/Pi:index Pi] digital audio is now mixed in, since 3.0 cores).

Latest revision as of 11:50, 4 May 2020

Number $xxFE
Decimal 254
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 Keyboard ($**FE / 254). 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).