Chapter 3 Programming Your Universal Counter for Remote Operation
Status Reporting
3-22 Programming Guide
Table 3-4. Status Byte Register
BIT WEIGH
T
SYMBOL DESCRIPTION
0 Not used
1 Not used
2 Not used
3 8 QSB
Questionable Data/Signal Status Register
Summary Bit
4 16 MAV Message Available Summary Bit
5 32 ESB Standard Event Status Register Summary Bit
6 64 RQS/MSS Request Service/Master Status Summary Bit
7 128 OSB Operation Status Register Summary Bit
A detailed description of each bit in the Status Byte Register follows:
• Bits 0–2 are not used.
• Bit 3 (QSB) summarizes the Questionable Data/Signal Status Event
Register.
This bit indicates whether or not one or more of the enabled Questionable
Data/Signal events have occurred since the last reading or clearing of the
Questionable Data/Signal Status Event Register.
This bit is set TRUE (one) when an enabled event in the Questionable
Data/Signal Status Event Register is set TRUE. Conversely, this bit is set
FALSE (zero) when no enabled events are set TRUE.
• Bit 4 (MAV) summarizes the Output Queue.
This bit indicates whether or not the Output Queue is empty.
This bit is set TRUE (one) when the Counter is ready to accept a request
by the external computer to output data bytes; that is, the Output Queue is
not empty. This bit is set FALSE (zero) when the Output Queue is empty.