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CVMEModule

Name

CVMEModule  -- Provide a base set of services for a VME module driver class.

Synopsis


#include <VmeModule.h>
         
 class CVmeModule {

  CVmeModule(CVmeModule::Space space, UInt_t base, UInt_t length, int nCrate = 0);
  CVmeModule(const CVmeModule& aCVmeModule);

  CVmeModule& operator=(const CVmeModule& aCVmeModule);
  int operator==(const CVmeModule& aCVmeModule);
  UChar_t peekb(UInt_t offset = 0);
  UShort_t peekw(UInt_t offset = 0);
  ULong_t peekl(UInt_t offset = 0);
  void pokeb((Char_t byte, UInt_t nOffset);
  void pokew(UShort_t word, UInt_t nOffset);
  void pokel(ULong_t lword, UInt_t nOffset);
  UInt_t readl(void* pBuffer, UInt_t nOffset, size_t longs);
  UInt_t readw(void* pBuffer, UInt_t nOffset, size_t words);
  UInt_t readb(void* pBuffer, UInt_t nOffset, size_t bytes);
}

Description

This class provides base methods and facilities on which you can build a class to drive a specific hardware module. This can be done either by extension (public inheritance), by layering (protected/private inheritance), or composition as you choose.

Public member functions

CVmeModule(CVmeModule::Space space, UInt_t base, UInt_t length, int nCrate = 0);

Base class constructor. The base class encapsulates a CVME object. This constructor provides the information requried to build that. space, base and length describe the addresss window and address modifier that will access the module. nCrate selects in which of the VME crates the module is located.

CVmeModule(const CVmeModule& aCVmeModule);

Provides copy construction of this base class. It is not necessary, and sometimes not possible for subclasses to provide a copy constructor. In that case, the recommended procedure is for the subclass to declare a private copy constructor but never implement it.

CVmeModule& operator=(const CVmeModule& aCVmeModule);

Provides for assignment of the base class. It may not be possible for the subclass to provide that function. In that case, see the remarks for the copy constructor for the recommended procedure.

int operator==(const CVmeModule& aCVmeModule);

Provides base class support for an equality comparison. If this cannot be provided in a derived class see the notes for the copy constructor.

UChar_t peekb(UInt_t offset = 0);

Fetches a byte from the address window defined in the constructor. offset is the byte offset from the base of that address window to the byte fetched.

UShort_t peekw(UInt_t offset = 0);

Same as peekb however a 16 bit word is returned and offset is a word offset.

ULong_t peekl(UInt_t offset = 0);

Same as peekb however a 32 bit longword is returned, and offset is a longword offset.

void pokeb((Char_t byte, UInt_t nOffset);

Writes an 8 bit byte to the address window created by the constructor. byte is written to nOffset bytes from the base of the base address of the window.

void pokew(UShort_t word, UInt_t nOffset);

Same as pokeb however a 16 bit word is written to nOffset words from the base address of the address window.

void pokel(ULong_t lword, UInt_t nOffset);

Same as pokeb however a 32 bit lword is written to nOffset longwords fromt he base address of the address window.

UInt_t readl(void* pBuffer, UInt_t nOffset, size_t longs);

Reads a block from the VME bus address window defined by this module. The block read starts at nOffset longwords from the start of the window and is longs longwords long. The block is transferred into the buffer pointed to by pBuffer. On success, the function returns the number of longwords read.

Where possible, this function performs each read at a longword width.

UInt_t readw(void* pBuffer, UInt_t nOffset, size_t words);

Same as readl however, nOffset is a word (16 bit) offset and words counts the number of 16 bit words to read. All transfers are done in 16 bit width if possible.

UInt_t readb(void* pBuffer, UInt_t nOffset, size_t bytes);

Same as readl however nOffset is an 8 bit offset and bytes is a byte count. All transfers are done 8 bit wide if possible).

Types and public data

In parallel with the address space selectors in CVME, this module defines the type CVmeModule::Space which is an enumerated type with the following values defined:

a16d16

Selects Short I/O space note that the data width is not actually restricted to 16 bits.

a24d16 and a24d32

Selects A24 addressing with no actual data width restriction.

a32d32

Selects A32 addresssing.

geo

Selects geographical addressing for backplanes that include the CERN P3 connector.

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