Pia Class Reference
[PIA/VIA]

#include <PiaVia.h>

Inherits PiaVia.

Inherited by RB8506_Pia, and RB8506_Sifu.

List of all members.

Detailed Description

This is the driver for the Parallel Interface module with the Motorola MC6821 Peripheral Interface Adapter (PIA).

A PIA has the following registers:

   Registers       Offset  Rd/Wr   Description
   ------------------------------------------------------------------------------
   PRDA            0       rd/wr   port A peripheral data register (CRA bit 2 = 1)
   DDRA            0       rd/wr   port A data direction register  (CRA bit 2 = 0)
   CRA             1       rd/wr   port A control register
   PRDB            2       rd/wr   port B peripheral data register (CRB bit 2 = 1)
   DDRB            2       rd/wr   port B data direction register  (CRB bit 2 = 0)
   CRB             3       rd/wr   port B control register

Each of the peripheral data lines (PA0..PA7, PB0..PB7) can be programmed to act as an input or as an output. This is accomplished by setting a "1" in the corresponding Data Direction Register bit for those lines which are to be outputs. A "0" in a bit of the Data Direction Register causes the corresponding peripheral data line to act as an input.

Peripheral Data Register: 

   76543210 : data bits 0..7, 0 for low, 1 for high output.

Data Direction Register: 

   76543210 : data direction bits, 0 for input, 1 for output.

Control Register (CRA): 

   76543210

   7        : IRQA1 interrupt flag
              Goes high on active transition of CA1.
              Automatically cleared by MPU read of output register A.
              May also be cleared by hardware reset.

    6       : IRQA2 interrupt flag
              When CA2 is an input, IRQA2 goes high on active transition of CA2.
              Automatically cleared by MPU read of output register A.
              May also be cleared by hardware reset.

     543    : CA2 control
              543 : CA2 input
              5   : 0 : CA2 input
               4  : CA2 active transition for setting IRQA2 flag
                    0 : IRQA2 set by high-to-low transition on CA2
                    1 : IRQA2 set by low-to-high transition on CA2
                3 : CA2 interrupt request enable
                    0 : disable IRQA2 interrupt on active transition of CA2
                    1 : enable  IRQA2 interrupt on active transition of CA2

              543 : CA2 output
              5   : 1 : CA2 output
               43 : CA2 output control
                    0x: strobed CA2 output (operation of CB2 is not identical)
                    1x: programmed CA2 output with level of bit 3
                    00: CA2 Read Strobe with CA1 restore
                    01: CA2 Read Strobe with E   restore
                   (00: CB2 Read Strobe with CB1 restore)
                   (01: CB2 Read Strobe with E   restore)
                    10: CA2 low
                    11: CA2 high

        2   : data direction register access
              0 : Data Direction Register selected
              1 : Peripheral Data Register selected

         1  : CA1 active transition for setting IRQA1
              0 : IRQA1 set by high-to-low transition on CA1
              1 : IRQA1 set by low-to-high transition on CA1

          0 : CA1 interrupt enable
              0 : CA1 interrupt disabled
              1 : CA1 interrupt enabled


Public Member Functions

Construction
 Pia (NameCref aName, Addr aAddr=DEF_ADDR, Rack aRack=DEF_RACK)
 constructor; may throw RulbusOpenError

virtual ~Pia ()
 destructor (no-op)

Accessors -- port A
int getIrqCA1 ()
 CA1 input: test for interrupt request pending.

char getEdgeCA1 ()
 CA1 input: get active edge ['p','n'].

int getIntrCA1 ()
 CA1 input: get interrupt enable state.

char getDirCA2 ()
 CA2 i/o: get data direction ['i','o'].

int getLevelCA2 ()
 CA2 i/o: get level [0,1].

Accessors -- port B
int getIrqCB1 ()
 CB1 input: test for interrupt request pending.

char getEdgeCB1 ()
 CB1 input: get active edge ['p','n'].

int getIntrCB1 ()
 CB1 input: get interrupt enable state.

char getDirCB2 ()
 CB2 i/o: get data direction ['i','o'].

int getLevelCB2 ()
 CB2 i/o: get level [0,1].

Mutators -- port A
void setEdgeCA1 (char edge)
 CA1 input: set active edge ['p','n']; may throw RulbusRangeError.

int setIntrCA1 (int enable)
 CA1 input: enable/disable interrupt.

void setDirCA2 (char dir)
 CA2 i/o: set data direction ['i','o']; may throw RulbusRangeError.

void setLevelCA2 (int lvl)
 CA2 i/o: set level [0,!0]; may throw RulbusContextError.

Mutators -- port B
void setEdgeCB1 (char edge)
 CB1 input: set active edge ['p','n']; may throw RulbusRangeError.

int setIntrCB1 (int enable)
 CB1 input: enable/disable interrupt.

void setDirCB2 (char dir)
 CB2 i/o: set data direction ['i','o']; may throw RulbusRangeError.

void setLevelCB2 (int lvl)
 CB2 i/o: set level [0,!0]; may throw RulbusContextError.


Static Public Attributes

Defaults
const int DEF_ADDR = 0x90
 default rulbus address

const int DEF_RACK = 0
 default rack


Protected Member Functions

Accessors -- port A, B
int getDDRA ()
 Port A: get data direction register.

int getPDRA ()
 Port A: get peripheral data register.

int getDDRB ()
 Port B: get data direction register.

int getPDRB ()
 Port B: get peripheral data register.

Mutators -- port A, B
void setDDRA (int dir)
 Port A: set data direction register.

void setPDRA (int dat)
 Port A: set peripheral data register.

void setDDRB (int dir)
 Port B: set data direction register.

void setPDRB (int dat)
 Port B: set peripheral data register.


Private Member Functions

Register selectors -- port A, B
void select_ddra ()
 Port A: provide access to data direction register.

void select_pdra ()
 Port A: provide access to peripheral data register.

void select_ddrb ()
 Port B: provide access to data direction register.

void select_pdrb ()
 Port B: provide access to peripheral data register.

Control ports A/B, C1 (input only)
int getIrqC1 (int offset)
 C[AB]1: test for interrupt request pending.

char getEdgeC1 (int offset)
 C[AB]1: get active edge ['p','n'].

void setEdgeC1 (int offset, char edge, char port)
 C[AB]1: set active edge ['p','n']; may throw RulbusRangeError.

int getIntrC1 (int offset)
 C[AB]1: get interrupt enable state.

int setIntrC1 (int offset, int enable)
 C[AB]1: enable/disable interrupt.

Control port A/B, C2 (input and output)
char getDirC2 (int offset)
 C[AB]2: get data direction.

void setDirC2 (int offset, char dir, char port)
 C[AB]2: set data direction; may throw RulbusRangeError.

int getLevelC2 (int offset)
 C[AB]2: get line level.

void setLevelC2 (int offset, int lvl, char port)
 C[AB]2: set line level; may throw RulbusContextError.


Static Private Attributes

Register offsets
const int OFF_DDRA = 0
 data direction register A

const int OFF_PDRA = 0
 peripheral data register A

const int OFF_CRA = 1
 control register A

const int OFF_DDRB = 2
 data direction register B

const int OFF_PDRB = 2
 peripheral data register B

const int OFF_CRB = 3
 control register B

const int ADR_WIDTH = OFF_CRB + 1
 address with

Bit masks for CA1/CB1
const int MSK_EIC1 = 0x01
 enable interrupt on active transition of CA1/CB1

const int MSK_ATC1 = 0x02
 active transition of CA1/CB1 if ...

const int MSK_SPDR = 0x04
 select peripheral data register A/B

Bit masks for CA2/CB2: NOTE: Read/Write strobe not supported
const int MSK_DIRC2 = 0x20
 CA2/CB2 direction (0:in, 1:out).

CA2/CB2 input:
const int MSK_ATC2 = 0x10
 active transition of CA2/CB2 if ...

const int MSK_EIC2 = 0x08
 enable interrupt on active transition of CA2/CB2

CA2/CB2 output:
const int MSK_POC2 = 0x10
 CA2/CB2 programmed output.

const int MSK_OLC2 = 0x08
 CA2/CB2 output level.

CA1/CB1, CA2/CB2 interrupt request
const int MSK_IRQ1 = 0x80
 interrupt request for CA1/CB1

const int MSK_IRQ2 = 0x40
 interrupt request for CA2/CB2

The documentation for this class was generated from the following files:
Generated on Tue Oct 12 14:12:04 2004 for Rulbus Device Class Library for Microsoft Windows by doxygen 1.3.4