signal

Documentation

Overview

Package signal exposes the interface between the VCS and the television implementation.

Index

• Constants
• type ColorSignal
• type SignalAttributes
  • func (a SignalAttributes) String() string
• type StateAdj
• type StateReq
• type TelevisionSprite
• type TelevisionTIA

Constants

const (
	AudioChannel0Shift = 5
	AudioChannel1Shift = 13
	ColorShift         = 21
	ScanlineShift      = 29
	ClockShift         = 38
)

List of shift amounts to be used to access the corresponding bits in a SignalAttributes value.

const NoSignal = Scanline | Clock

NoSignal is the null value of the SignalAttributes type. It is assumed that a TV scanline/clock value of 511x255 is impossible and so can never be confused with a real signal

In an array of SignalAttributes a NoSignal indicates the end of the array - processing should stop.

Types

type ColorSignal

type ColorSignal uint8

ColorSignal represents the signal that is sent from the VCS to the television.

const VideoBlack ColorSignal = 0xff

VideoBlack is the ColorSignal value that indicates no pixel is being output.

type SignalAttributes

type SignalAttributes uint64

SignalAttributes represents the data sent to the television.

const (
	VSync         SignalAttributes = 0b0000000000000000000000000000000000000000000001
	VBlank        SignalAttributes = 0b0000000000000000000000000000000000000000000010
	CBurst        SignalAttributes = 0b0000000000000000000000000000000000000000000100
	HSync         SignalAttributes = 0b0000000000000000000000000000000000000000001000
	AudioUpdate   SignalAttributes = 0b0000000000000000000000000000000000000000010000
	AudioChannel0 SignalAttributes = 0b0000000000000000000000000000000001111111100000 // 8 bits
	AudioChannel1 SignalAttributes = 0b0000000000000000000000000111111110000000000000 // 8 bits
	Color         SignalAttributes = 0b0000000000000000011111111000000000000000000000 // 8 bits
	Scanline      SignalAttributes = 0b0000000011111111100000000000000000000000000000 // 9 bits
	Clock         SignalAttributes = 0b1111111100000000000000000000000000000000000000 // 8 bits (signed)
)

List of bit masks to be used to with the SignalAttribute type.

func (SignalAttributes) String

func (a SignalAttributes) String() string

type StateAdj

type StateAdj int

StateAdj is used to specify adjustment scale for the ReqAdjust() function.

const (
	AdjFramenum StateAdj = iota
	AdjScanline
	AdjInstruction
	AdjCPUCycle
	AdjClock
)

List of valid adjustment scales.

type StateReq

type StateReq int

StateReq is used to identify which television attribute is being asked with the GetState() function.

const (
	ReqFramenum StateReq = iota
	ReqScanline
	ReqClock
)

List of valid state requests.

type TelevisionSprite

type TelevisionSprite interface {
	GetState(StateReq) int
}

TelevisionSprite exposes only the functions required by the video sprites.

type TelevisionTIA

type TelevisionTIA interface {
	Signal(SignalAttributes) error
	GetState(StateReq) int
}

TelevisionTIA exposes only the functions required by the TIA.