PiaVia Class Reference
[PIA/VIA]

#include <PiaVia.h>

Inherits RulbusDevice.

Inherited by Pia, and Via.

List of all members.

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Detailed Description

Pia and Via have roughly the same capabilities with respect to their inputs and outputs. Interface class PiaVia expresses this simlarity and it captures the properties common to Pia and Via.

PIA and VIA offer the following interface pins.

    port       pin   direction  description
       A  PA0..PA7      i/o     level inputs and outputs
       A       CA1     input    active edge transition sets interrupt flag
       A       CA2      i/o     complex operation
       B  PB0..PB7      i/o     level inputs and outputs
       B       CB1     input    active edge transition sets interrupt flag
       B       CB2      i/o     complex operation
   

See Pia and Via for a more detailed description of the IC's capabilities.

Methods

The PiaVia interface contains the following groups of peripheral i/o methods:

• unified port-related methods, like getPortData():
  port names are "CA", "CB", "PA" and "PB"
• unified line-related methods, like setLineDir():
  line names are "CA1", "CA2" "PA0".."PA7" and "CB1", "CB2" "PB0".."PB7"
• specific-port methods, like setDirPA()
• specific-line methods, like getLevelCA2()

The port-related functions allow you to read or write a complete port at one time, or to get or set its data direction.

However, if you want to act on a single line, the line-related functions are more convenient to use.

The following tables show the port names and the bit-positions for the various peripheral lines as used in the unified port-related functions and the line names and data-direction specifications for the unified line- related functions.

           bit                                    direction   active edge
    port   7  6  5  4  3  2  1  0          line   in    out    neg   pos
    -------------------------------        -------------------------------
    "PA"  PA7 .  .  .  .  .  .  PA0        "PAn"  'i'   'o'
    "CA"                    CA2 CA1        "CA1"               'n'   'p'
                                           "CA2"  'i'   'o'
    "PB"  PB7 .  .  .  .  .  .  PB0        "PBn"  'i'   'o'
    "CB"                    CB2 CB1        "CB1"               'n'   'p'
                                           "CB2"  'i'   'o'

     peripheral lines bit-positions        peripheral lines data-direction
         for port-related functions        for line-related functions
           (i/o and data-direction)        (n: 0..7)
   

When setting data direction, a 0 in the bitmask makes a line input, whereas a 1 makes it an output. For CA1 and CB1, a 0 makes the input act on the negative edge, a 1 makes it sensitive to the positive, upgoing edge.

When setting output, a 0 in the bitmask makes the line level low, whereas a 1 makes it high.

When reading data-direction from port CA or CB, the CA1 and CA2 (CB1 and CB2) data-direction settings are combined as follows:

 int dir = ( getDirCA2() != 'i' ) << 1 ) | getEdgeCA1() != 'n';

When reading port CA, or CB the CA1 and CA2 (CB1 and CB2) lines are combined as follows:

 int data = ( getLevelCA2() << 1 ) | getIrqCA1();

So to set PB0..PB1 and CB2 to output and to set PB2..PB3 to input, you may write (pia already created):

   pia.setPortDir( "PB", 0x03 );
   pia.setPortDir( "CB", 0x02 );

Note that this ignores the previous data-direction setting: it also sets PB4..PB7 to input.

The following code also sets PB0..PB1 and CB2 to output and PB2..PB3 to input, but leaves the other lines unaffected.

   pia.setLineDir( "PB0", 'o' );
   pia.setLineDir( "PB1", 'o' );
   pia.setLineDir( "CB2", 'o' );
   pia.setLineDir( "PB2", 'i' );
   pia.setLineDir( "PB3", 'i' );

To do the equivalent with the port-related functions you could write:

   int32 dir = pia.getPortDir( "PB" ); pia.setPortDir( "PB", (dir & ~0x0F ) | 0x03 );
         dir = pia.getPortDir( "CB" ); pia.setPortDir( "CB",  dir |  0x02 );

With dir & ~0x0F we first clear the bits for lines we want to define, PB0..PB3 (0x0F is 00001111 binary).

Note that for CB2 we just as well could write pia.setPortDir( "CB", 0x02 ) as before, since it is the only output-capable line of port CB (setting CB1's data-direction is silently ignored).

Bitmasks

To address specific pins in port data, you need to use a bitmask. For example, a bitmask of 0x21 specifies pin 0 and pin 5. The mask can also be made with:

 1 << 5 | 1 << 0 

Having read direction or data, you use the bitmask to select the pin(s) you are interested in, for example:

 char dir_pin5 = ( direction_read & (1 << 5) ) ? 'o' : 'i'; 

See par.cpp for an example program. It contains several bit-manipulation functions.

Examples:

pport.cpp.

Public Member Functions
Construction
	PiaVia (NameCref aName, Addr aAddr, Addr aWidth, Rack aRack)
virtual	~PiaVia ()
	destructor (empty)
Accessors -- generic ports
virtual int	getPortDir (CharCptr prt)
	get port data direction; may throw RulbusRangeError.
virtual int	getPortData (CharCptr ptr)
	get port data; may throw RulbusRangeError.
virtual char	getLineDir (CharCptr lin)
	get line direction; may throw RulbusRangeError.
virtual int	getLineLevel (CharCptr lin)
	get linelevel; may throw RulbusRangeError.
Accessors -- port A
virtual int	getDirPA ()
	Port A: get data direction.
virtual int	getDataPA ()
	Port A: get peripheral data.
virtual char	getLineDirPA (int pin)
	Port A: get peripheral line direction; may throw RulbusRangeError.
virtual int	getLineLevelPA (int pin)
	Port A: get peripheral line; may throw RulbusRangeError.
Accessors -- port B
virtual int	getDirPB ()
	Port B: get data direction.
virtual int	getDataPB ()
	Port B: get peripheral data.
virtual char	getLineDirPB (int pin)
	Port B: get peripheral line direction; may throw RulbusRangeError.
virtual int	getLineLevelPB (int pin)
	Port B: get peripheral line; may throw RulbusRangeError.
Accessors -- port CA
virtual int	getIrqCA1 ()=0
	CA1 input: interrupt request pending.
virtual char	getEdgeCA1 ()=0
	CA1 input: get active edge ['p','n'].
virtual int	getIntrCA1 ()=0
	CA1 input: get interrupt enable state.
virtual char	getDirCA2 ()=0
	CA2 i/o: get data direction ['i','o'].
virtual int	getLevelCA2 ()=0
	CA2 i/o: get level [0,1].
Accessors -- port CB
virtual int	getIrqCB1 ()=0
	CB1 input: interrupt request pending.
virtual char	getEdgeCB1 ()=0
	CB1 input: get active edge ['p','n'].
virtual int	getIntrCB1 ()=0
	CB1 input: get interrupt enable state.
virtual char	getDirCB2 ()=0
	CB2 i/o: get data direction ['i','o'].
virtual int	getLevelCB2 ()=0
	CB2 i/o: get level [0,1].
Mutators -- generic ports
virtual void	setPortDir (CharCptr prt, int msk)
	set port data direction; may throw RulbusRangeError.
virtual void	setPortData (CharCptr prt, int dat)
	set port data; may throw RulbusContextError (CA2, CB2), RulbusRangeError.
virtual void	setLineDir (CharCptr lin, char dir)
	set line direction; may throw RulbusRangeError.
virtual void	setLineLevel (CharCptr lin, int lvl)
	set specified ouput linelevel; may throw RulbusContextError, RulbusRangeError.
Mutators -- port A
virtual void	setDirPA (int msk)
	Port A: set data direction; may throw RulbusRangeError.
virtual void	setDataPA (int dat)
	Port A: set peripheral data; may throw RulbusRangeError.
virtual void	setLineDirPA (int pin, char dir)
	Port A: set peripheral line direction; may throw RulbusRangeError.
virtual void	setLineLevelPA (int pin, int lvl)
	Port A: set peripheral line; may throw RulbusContextError, RulbusRangeError.
Mutators -- port B
virtual void	setDirPB (int msk)
	Port B: set data direction; may throw RulbusRangeError.
virtual void	setDataPB (int dat)
	Port B: set peripheral data; may throw RulbusRangeError.
virtual void	setLineDirPB (int pin, char dir)
	Port B: set peripheral line direction; may throw RulbusRangeError.
virtual void	setLineLevelPB (int pin, int lvl)
	Port B: set peripheral line; may throw RulbusContextError, RulbusRangeError.
Mutators -- port CA
virtual void	setEdgeCA1 (char edge)=0
	CA1 input: set active edge ['p','n'].
virtual int	setIntrCA1 (int enable)=0
	CA1 input: enable/disable interrupt.
virtual void	setDirCA2 (char dir)=0
	CA2 i/o: set data direction ['i','o']; may throw RulbusRangeError.
virtual void	setLevelCA2 (int lvl)=0
	CA2 i/o: set level [0,!0]; may throw RulbusContextError.
Mutators -- port CB
virtual void	setEdgeCB1 (char edge)=0
	CB1 input: set active edge ['p','n']; may throw RulbusRangeError.
virtual int	setIntrCB1 (int enable)=0
	CB1 input: enable/disable interrupt.
virtual void	setDirCB2 (char dir)=0
	CB2 i/o: set data direction ['i','o']; may throw RulbusRangeError.
virtual void	setLevelCB2 (int lvl)=0
	CB2 i/o: set level [0,!0]; may throw RulbusContextError.
Protected Member Functions
Checkers
void	checkPin (int pin)
	check for valid pin ([0-7]; may throw RulbusRangeError
void	checkDir (char dir)
	check for valid dir ([iIoO]; may throw RulbusRangeError
void	checkData (int dat)
	check for valid data ([0-0xFF]; may throw RulbusRangeError
void	checkMask (int msk)
	check for valid mask ([0-0xFF]; may throw RulbusRangeError
Accessors -- port A, B
virtual int	getDDRA ()=0
	Port A: get data direction register.
virtual int	getPDRA ()=0
	Port A: get peripheral data register.
virtual int	getDDRB ()=0
	Port B: get data direction register.
virtual int	getPDRB ()=0
	Port B: get peripheral data register.
Mutators -- port A, B
virtual void	setDDRA (int dir)=0
	Port A: set data directionregister.
virtual void	setPDRA (int dat)=0
	Port A: set peripheral data register.
virtual void	setDDRB (int dir)=0
	Port B: set data direction register.
virtual void	setPDRB (int dat)=0
	Port B: set peripheral data register.

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

• PiaVia.h
• PiaVia.cpp

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