Slot number/$0200 Index	$0420 address (%000000SX)	$0400 address/bit position
$00 / $000	$0420	$0400 / %------SX
$01 / $004	$0421	$0400 / %----SX--
$02 / $008	$0422	$0400 / %--SX----
$03 / $00C	$0423	$0400 / %SX------
$04 / $010	$0424	$0401 / %------SX
$05 / $014	$0425	$0401 / %----SX--
$06 / $018	$0426	$0401 / %--SX----
$07 / $01C	$0427	$0401 / %SX------
$08 / $020	$0428	$0402 / %------SX
...	...	...
$7F / $1FC	$049F	$041F / %SX------