Class: Amaterasu::GameBoy::Serial

Inherits:
Object
  • Object
show all
Defined in:
lib/amaterasu/game_boy/serial.rb

Overview

Models the Serial Port present in the Game Boy.

  • Very useful for performing community accuracy tests, they use the serial to output results.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(interrupts, trace_serial: false) ⇒ Serial

Creates a serial port instance.

  • Needs to hold an instance of interrupts to request a :serial interrupt.

  • Holds the state of the Transfer Data and Control registers.



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# File 'lib/amaterasu/game_boy/serial.rb', line 19

def initialize(interrupts, trace_serial: false)
  @interrupts = interrupts
  @trace_serial = trace_serial

  @sb = 0x00
  @sc = 0xFF

  @message_buffer = Array.new
end

Instance Attribute Details

#message_buffer ⇒ Object (readonly)

Returns an Array with all the bytes from the serial transfer.



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# File 'lib/amaterasu/game_boy/serial.rb', line 13

def message_buffer
  @message_buffer
end

#sb ⇒ Object

Returns the 8-bit value stored in the SB (Serial Transfer Data) register.



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# File 'lib/amaterasu/game_boy/serial.rb', line 10

def sb
  @sb
end

Instance Method Details

#sc ⇒ Object

Returns the 8-bit value stored in the SC (Serial Transfer Control) register.

  • In the actual hardware only Bit 7 and Bit 0 are wired.

  • Bits 6-1 always return 1 when read.



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# File 'lib/amaterasu/game_boy/serial.rb', line 33

def sc
  @sc | 0b01111110
end

#sc=(value) ⇒ Object

Sets a 8-bit value into the SC register.

  • Bits 6-1 are ignored since they are not wired to anything.

  • If bit 7 goes from 0 -> 1, a transfer is started.



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# File 'lib/amaterasu/game_boy/serial.rb', line 46

def sc=(value)
  @sc = value & 0b10000001

  start_transfer if transfer_enabled?
end