[Cyan]<CedarChest6.0>GPIB>GPIB.mesa!4

GPIB.mesa

Last edited by Neil Gunther, November 8, 1985 1:57:25 pm PST

Tim Diebert: March 25, 1986 10:44:41 am PST

Last Edited by: Gasbarro March 4, 1986 10:25:28 am PST

This interface defines the IEEE 488 General Purpose Interface Bus (GPIB) standard for asynchronous byte serial bit parallel interfacing to instrumentation. It contains all the standard commands, both universal and selected, and data transfer PROC's. To keep machine-dependent applications organized, this PUBLIC interface is EXPORTED by the appropriate driver-level implementation which must be bound into the client's configuration.

IEEE 488 Technical Parameters:

o Maximum transmission length = 20 meters/bus; 2m/device; Star or Linear network.
o Maximum number of devices/bus = 15; 1 talker/14 listeners.
o Maximum data rate = 1Mbps for short paths; ~300 Kbps typical; device limited.
o Signals: 8 data/8 control simultaneously active.
o Data Transfer: byte serial bit parallel, asynchronous, with 3-wire handshake.
o Only one controller may be active at once. The sytem controller is the master.

For the formal bus specification see: IEEE Standard Digital Interface for Programmable Instrumentation, ANSI/IEEE Std 488-1978 and ANSI/IEEE Std 728-1982.

DIRECTORY Rope;

GPIB: DEFINITIONS = BEGIN

Types and Constants

Bus Status

StatusFlag: TYPE = {
DAV, -- Data Valid
NRFD, -- Not Ready For Data
NDAC, -- NOT Data Accepted
IFC, -- Interface Cleared
SRQ, -- Service Request
REN, -- Remote Enable
EOI, -- End or Identify
ATN -- Attention [switch Command/Data modes]
};

maxWriteBuffer: NAT = 512+5;

maxReadBuffer: NAT = 512+5;

StatusVec: TYPE = ARRAY StatusFlag OF BOOL;

SRQLabels: TYPE = ARRAY StatusFlag OF Rope.ROPE;

Command Group

goToLocal: CHAR = 001C; -- GTL

selectedDeviceClear: CHAR = 004C; -- SDC

parallelPollConfigure: CHAR = 005C; -- PPC

groupExecuteTrigger: CHAR = 010C; -- GET

takeControl: CHAR = 011C; -- TCT

localLockout: CHAR = 021C; -- LLO

devicesClear: CHAR = 024C; -- DCL

parallelPollUnconfigure: CHAR = 025C; -- PPU

serialPollEnable: CHAR = 030C; -- SPE

serialPollDisable: CHAR = 031C; -- SPD

parallelPollEnable: SecondaryCommand = 140C; -- PPE

parallelPollDisable: SecondaryCommand = 160C; -- PPD

Listen/Talk Address Groups

ListenAddress: TYPE = CHAR [040C..077C];

UnListen: ListenAddress = 077C;

TalkAddress: TYPE = CHAR [100C..137C];

UnTalk: TalkAddress = 137C;

SecondaryCommand: TYPE = CHAR [100C..177C];

FORMAT: TYPE = {F0, F1, F2, F3, F4, F5};

PrimaryAddress: TYPE = CHAR [040C..137C];

DeviceAddr: TYPE = NAT [0..31);

Terminator: TYPE = {CR, LF, EOI};

Procedures

Universal commands (all devices whether addressed or not)

Command: PROC [sendMsg: Rope.ROPE];

DevicesClear: PROC;

GoToLocal: PROC;

GroupExecuteTrigger: PROC;

InterfaceClear: PROC;

LocalLockout: PROC;

RemoteEnable: PROC;

Selected Device Commands (only those devices addressed)

SelectedDeviceClear: PROC [device: DeviceAddr];

SelectedGoToLocal: PROC [device: DeviceAddr];

SelectedGroupEnableTrigger: PROC [device: DeviceAddr];

SelectedRemoteEnable: PROC [device: DeviceAddr];

Explicit Polling Routines

ParallelPollConfigure: PROC [device: DeviceAddr];

ParallelPollUnconfigure: PROC;

SelectedParallelPollConfigure: PROC [device: DeviceAddr];

SelectedParallelPollUnconfigure: PROC [device: DeviceAddr];

Read Specific Devices

PollDevice: PROC [device: DeviceAddr, labels: SRQLabels];

ReadDevice: PROC [device: DeviceAddr, terminator: Terminator ← EOI]
RETURNS [recvMsg: Rope.ROPE];

ReadOnInterrupt: PROC [device: DeviceAddr, recvMsg: Rope.ROPE, labels: SRQLabels];

SelectedReadSerialPoll: PROC [device: DeviceAddr] RETURNS [statusByte: CHAR];

ReadStatusByte: PROC [device: DeviceAddr] RETURNS [char: CHAR];

Write Specific Devices

WriteDevice: PROC [device: DeviceAddr, sendMsg: Rope.ROPE];

WriteDeviceBuffered: PROC [device: DeviceAddr, sendMsg: Rope.ROPE, hold: BOOL];

Uses a double buffer scheme to make RPC go faster. Set hold: TRUE on last packet of buffer to ensure syncronization with next command.

Convenience Functions

InitializeController: PROC RETURNS [open: BOOL];

FinalizeController: PROC;

SRQAsserted: PROC RETURNS [asserted: BOOL];

Printer Functions (see Tim Diebert)

WriteDeviceInitial: PROC [device: DeviceAddr, sendMsg: Rope.ROPE];

-- Sends the string without asserting EOI.

WriteDeviceContinued: PROC [device: DeviceAddr, sendMsg: Rope.ROPE, last: BOOL];

-- Sends the string without the initial stuff.

WriteDeviceBlock: UNSAFE PROC [device: DeviceAddr,
lp: LONG POINTER TO WORD, -- For Lupine --
quadWordCnt: CARDINAL, last: BOOL];

-- Sends the bytes pointed to by lp, the total bytes count must be a multiple of 8.

WriteDMABlock: UNSAFE PROC [device: DeviceAddr,
multiBusAddress: LONG POINTER TO WORD, -- For Lupine --
byteCnt: CARDINAL, last: BOOL];

-- Sends the bytes pointed to by multiBusAddress from the MultiBus Memory card in the busmaster.

CheckDMADone: PROC RETURNS [BOOL];

Indicates that the DMA transfer is complete and the controller is willing to start another.

END.