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Intel8255 Class Reference

Intel 8255 base emulation class. More...

#include <8255.h>

Inheritance diagram for Intel8255:
PC98_Mouse_8255 PC98_System_8255

List of all members.

Public Types

enum  { PortA = 0, PortB = 1, PortC = 2 }

Public Member Functions

 Intel8255 ()
 Constructor.
virtual ~Intel8255 ()
 Destructor.
void reset (void)
 Reset state (as if activating reset signal)
void ackPortA (void)
 External acknowledgement of port A.
void ackPortB (void)
 External acknowledgement of port B.
virtual void strobePortA (void)
 Strobed Input (latch to port A)
virtual void strobePortB (void)
 Strobed Input (latch to port B)
uint8_t readPortA (void)
 Called when CPU reads port A.
uint8_t readPortB (void)
 Called when CPU reads port B.
uint8_t readPortC (void)
 Called when CPU reads port C.
uint8_t readControl (void)
 Called when CPU reads control port.
uint8_t readByPort (const uint8_t p03)
 Called when CPU reads from the chip.
void writePortA (const uint8_t data, uint8_t mask=0xFFU)
 Called when CPU writes port A.
void writePortB (const uint8_t data, uint8_t mask=0xFFU)
 Called when CPU writes port B.
void writePortC (const uint8_t data, uint8_t mask=0xFFU)
 Called when CPU writes port C.
void writeControl (const uint8_t data)
 Called when CPU writes control port.
void writeByPort (const uint8_t p03, const uint8_t data)
 Called when CPU writes to the chip.
virtual uint8_t inPortA (void) const
 Called by 8255 emulation to latch from port A pins.
virtual uint8_t inPortB (void) const
 Called by 8255 emulation to latch from port B pins.
virtual uint8_t inPortC (void) const
 Called by 8255 emulation to latch from port C pins.
virtual void outPortA (const uint8_t mask)
 Called by 8255 emulation when latching to port A pins.
virtual void outPortB (const uint8_t mask)
 Called by 8255 emulation when latching to port B pins.
virtual void outPortC (const uint8_t mask)
 Called by 8255 emulation when latching to port C pins.
void updateINTR_A (void)
 Internal 8255 emulation code to update INTR A signal.
void updateINTR_B (void)
 Internal 8255 emulation code to update INTR B signal.
void checkINTR_A (void)
 Internal 8255 emulation code to check INTR A change and dispatch signal.
void checkINTR_B (void)
 Internal 8255 emulation code to check INTR B change and dispatch signal.
virtual void sigINTR_A (void)
 Called by 8255 emulation when INTR A signal changes to dispatch signal.
virtual void sigINTR_B (void)
 Called by 8255 emulation when INTR B signal changes to dispatch signal.
const char * getName (void) const
 Retrieve the name of this chip (for debug/UI purposes)
const char * pinName (const unsigned int port, const unsigned int i) const
 Retrieve the name of a pin on the chip related to port A, B, or C (what it's connected to) (for debug/UI purposes)
const char * portName (const unsigned int port) const
 Retrieve the name of a port (A, B, or C) (for debug/UI purposes)

Public Attributes

uint8_t portAWriteMask
 Port A write mask. Controls which bits are writeable.
uint8_t portBWriteMask
 Port B write mask. Controls which bits are writeable.
uint8_t portCWriteMask
 Port C write mask. Controls which bits are writeable.
const char * ppiName
 PPI chip name (for debug/UI purposes)
const char * pinNames [3][8]
 Pin names (for debug/UI purposes)
const char * portNames [3]
 Port names (for debug/UI purposes)
uint8_t latchOutPortA
 Port A output latch.
uint8_t latchOutPortB
 Port B output latch.
uint8_t latchOutPortC
 Port C output latch.
uint8_t mode
 PPI mode byte.
bool IBF_A
 Input Buffer Full, port A contains information (port A, Mode 1)
bool IBF_B
 Input Buffer Full, port B contains information (port B, Mode 1)
bool OBF_A
 Output Buffer Full, port A contains information for the external device (port A, Mode 1)
bool OBF_B
 Output Buffer Full, port B contains information for the external device (port B, Mode 1)
bool INTR_A
 Interrupt Request A (to the microprocessor)
bool INTR_B
 Interrupt Request B (to the microprocessor)
bool pINTR_A
 Previous Interrupt Request A state (for change detection)
bool pINTR_B
 Previous Interrupt Request B state (for change detection)
bool INTE_1
 Interrupt 1 enable (mode 2)
bool INTE_2
 Interrupt 2 enable (mode 2)
bool INTE_A
 Interrupt A enable.
bool INTE_B
 Interrupt B enable.

Static Protected Member Functions

static const char * nil_if_null (const char *str)
 Return string "str", or "" (empty string) if str == NULL.

Detailed Description

Intel 8255 base emulation class.

Intel 8255 Programmable Peripheral Interface emulation class. The base class handles the functions and register I/O to emulate the 8255, while the subclass implements behavior of hardware attached to the 8255.

All emulation is written to follow Intel's datasheet as closely as possible.

Intel 8255A datasheet

NOTE: Mode 2 emulation has NOT been tested yet!

Definition at line 18 of file 8255.h.


Member Enumeration Documentation

anonymous enum

Port enumeration (A, B, and C)

Enumerator:
PortA 

Port A (input or output)

PortB 

Port B (input or output)

PortC 

Port C (input, output, or half input half output)

Definition at line 23 of file 8255.h.


The documentation for this class was generated from the following files: