Documentation
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Overview ¶
Package savekey implements the SaveKey external memory card. It contains 32KB of non-volatile memory. Suitable for saving high scores, game settings, etc.
The SaveKey type implements the ports.Peripheral interface and can be inserted into a VCS port like any other peripheral.
SaveKey information taken from "AtariVox Programmer's Guide" (16/11/04) by Alex Herbert
allocation list at https://atariage.com/atarivox/atarivox_mem_list.html (13/09/2020).
Index ¶
Constants ¶
const ( EEPROMsize = 0x8000 EEPROMpageSize = 0x40 EEPROMnumPages = EEPROMsize / EEPROMpageSize )
Variables ¶
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Functions ¶
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Types ¶
type Context ¶
type Context interface {
logger.Permission
}
type DataDirection ¶
type DataDirection int
DataDirection indicates the direction of data flow between the console and the SaveKey.
const ( Reading DataDirection = iota Writing )
Valid DataDirection values.
type EEPROM ¶
type EEPROM struct {
// the next address an i2c read/write operation will access
Address uint16
// current data
Data []uint8
// the data as it is on disk. data is mutable and we need a way of
// comparing what's on disk with what's in memory.
Disk []uint8
// contains filtered or unexported fields
}
EEPROM represents the non-volatile memory in the SaveKey peripheral.
type SaveKey ¶
type SaveKey struct {
// only two bits of the SWCHA value is of interest to the i2c protocol.
// from the perspective of the second player (in which port the SaveKey is
// usually inserted) pin 2 is the data signal (SDA) and pin 3 is the
// clock signal (SCL)
SDA i2c.Trace
SCL i2c.Trace
// incoming data is interpreted depending on the state of the i2c protocol.
// we also need to know the direction of data flow at any given time and
// whether the next bit should be acknowledged
State SaveKeyState
Dir DataDirection
Ack bool
// data is sent by the console one bit at a time. see recvBit(), sendBit() and resetBits()
Bits uint8
BitsCt int
// the core of the SaveKey is an EEPROM.
EEPROM *EEPROM
// contains filtered or unexported fields
}
SaveKey represents the SaveKey peripheral. It implements the Peripheral interface.
func NewSaveKey ¶
func NewSaveKey(ctx Context, r peripherals.RIOT, t peripherals.TIA, portRight bool) *SaveKey
NewSaveKey is the preferred method of initialisation for the SaveKey type.
func (*SaveKey) IsAnalogue ¶
func (*SaveKey) IsController ¶
type SaveKeyState ¶
type SaveKeyState int
SaveKeyState records how incoming signals to the SaveKey will be interpreted.
const ( SaveKeyStopped SaveKeyState = iota SaveKeyStarting SaveKeyAddressHi SaveKeyAddressLo SaveKeyData )
List of valid SaveKeyState values.
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