View source for Internal Port Decoding b16-23 Register

{{NextRegister
|Number=$84
|Readable=Yes
|Writable=Yes
|ShortDesc=Enabling internal ports decoding
}}
{|class="wikitable"
! Bit !! Description
|-
| 7 || (bit 23) Enabling {{PortNo|$xxDF}} (DAC mono Specdrum)
|-
| 6 || (bit 22) Enabling {{PortNo|$xxB3}} (DAC mono GS Covox)
|-
| 5 || (bit 21) Enabling {{PortNo|$xxFB}} (DAC mono Pentagon/ATM (sd mode 2 off))
|-
| 4 || (bit 20) Enabling {{PortNo|$xx0F}} and {{PortNo|$xx4F}} (DAC stereo Covox)
|-
| 3 || (bit 19) Enabling {{PortNo|$xx3F}} and {{PortNo|$xx5F}} (DAC stereo profi Covox)
|-
| 2 || (bit 18) Enabling {{PortNo|$xxF1}}, {{PortNo|$xxF3}}, {{PortNo|$xxF9}} and {{PortNo|$xxFB}} (DAC soundrive mode 2)
|-
| 1 || (bit 17) Enabling {{PortNo|$xx0F}}, {{PortNo|$xx1F}}, {{PortNo|$xx4F}} and {{PortNo|$xx5F}} (DAC soundrive mode 1)
|-
| 0 || (bit 16) Enabling {{PortNo|$FFFD}} and {{PortNo|$BFFD}}
|}

All bits are set to 1 upon soft reset.

(note: Next registers with number higher than $7F are inaccessible from Copper code)