Peripheral 4 Setting Register

Number	TBRegisterNumber::$09
Readable	TBRegisterReadable::Yes
Writable	TBRegisterWritable::Yes
Short Description	ShortDesc::Sets scanlines, AY mono output, Sprite-id lockstep, reset DivMMC mapram and disable HDMI audio.

Bit	Function
7	Enables AY2 "mono" output (A+B+C is sent to both R and L channels, makes it a bit louder than stereo mode).
6	Enables AY1 "mono" output (1 = mono, 0 default)
5	Enables AY0 "mono" output (0 after Hard-reset)
4	Sprite id lockstep (1 = {{#ask: TBRegisterNumber::$34 }} ($34) and {{#ask: PortNumber::$303B }} ($303B{{#ask: PortNumber::$303B |mainlabel=- |headers=hide |intro= /  |?NumberDec#- }}) are in lockstep, 0 default)
3	1 to reset mapram bit in DivMMC (was "Disables Kempston mouse port ($DF)" in core 2.0)
2	1 to silence HDMI audio (hard reset = 0) (since core 3.0.5) (was "Disables divMMC ports ($E3, $E7, $EB) if set" in core 2.0)
1-0	scanlines weight (0 after Hard-reset): (since core3.1.1) %00 = scanlines off, %01 = scanlines 50%, %10 = scanlines 25%, %11 = scanlines 12.5% (before: %00 = scanlines off, %01 = scanlines 75%, %10 = scanlines 50%, %11 = scanlines 25%)