Register Descriptions
Chapter 4
GPIB-1014 User Manual
4-56
© National Instruments Corporation
Channel Control Register
VMEbus Address:
Base A 07 (hex)
Attributes:
Read/Write, Internal to DMAC
7
6
5
4
3
2
1
0
STR
CNT
HLT
SAB
EINT
0
0
0
R/W
This register is used to control the operation of the channel. By writing to this register, a channel
operation can be started and set to be continued, halted, and aborted. Also, the channel can be
enabled to issue interrupts when an operation is terminated (normal or error termination). Setting
the STR bit causes immediate activation of the channel; the channel will be ready to accept
requests immediately. The STR and CNT bits of the register cannot be reset by a write to the
register. The software abort bit (SAB) can be used to terminate the operation. Setting the SAB
resets the STR and CNT. Setting the HLT bit halts the channel and resetting the HLT bit
resumes the operation.
Bit
Mnemonic
Description
7r/w
STR
Start Bit
The Start bit is used to start the operation of the channel.
0
=
No operation is pending
1
=
Start operation
6r/w
CNT
Continue Bit
The Continue bit is used to select the continue option. This bit must be
set when the channel is active or at the same time you set the STR bit.
Generally, this is not used for GPIB-1014 GPIB transfers.
0
=
No continuation is pending
1
=
Continue operation
5r/w
HLT
Halt Bit
The Halt bit is used to temporarily halt channel operation.
0
=
Operation not halted
1
=
Operation halted
4r/w
SAB
Software Abort Bit
The Software Abort bit is used to abort channel operation.
