8052 Specs

Kenwood

Port 0

Bit 0 = NOT Power-On-Reset (ARM)
Bit 1 = NOT Wakeup (ARM)
Bit 2 = NOT Reset (ARM)
Bit 3 = NOT Main Power (ARM)
Bit 4 = Cartridge Present
Bit 5 = Testing (???)
Bit 6 = NOT Boot Successful (ARM)
Bit 7 = ???

Port 1

Bit 0 = Write data from the PhatBox to the radio (Radio)
Bit 1 = Always 1 (???)
Bit 2 = Write interrupt (Radio)
Bit 3 = Read data from the radio to the PhatBox (Radio)
Bit 4 = ???
Bit 5 = PhatBox ready (Radio)
Bit 6 = Mute (Radio)
Bit 7 = ???

Port 2

Bit 0 = Data (DAC)
Bit 1 = Clock (DAC)
Bit 2 = Latch (DAC)
Bit 3 = NOT Write Protect (EEPROM)
Bit 4 = Clock (EEPROM)
Bit 5 = Data (EEPROM)
Bit 6 = Always 1 (???)
Bit 7 = ???

Port 3

Bit 0 = ???
Bit 1 = ???
Bit 2 = Read interrupt (Radio)
Bit 3 = Mode interrupt (Radio)
Bit 4 = ???
Bit 5 = Clock (Radio)
Bit 6 = NOT Voltage Regulator Error
Bit 7 = ???