The Status Model; Status Registers; Figure 3 The Registers And Filters For A Node - Agilent Technologies 8163A Programming Manual

The Status Model

Agilent 8163A/B, 8164A/B & 8166A/B Mainframes, Fifth Edition

The Status Model

Status Registers

Each node of the status circuitry has three registers:
• A condition register (CONDition), which contains the current status.
This register is updated continuously. It is not changed by having its
contents read.
• The event register (EVENt), which contains details of any positive
transitions in the corresponding condition register, that is, when a bit
changes from 0 → 1. The contents of this register are cleared when it is
read. The contents of any higher-level registers are affected with regard
to the appropriate bit.
• The enable register (ENABle), which enables changes in the event
register to affect the next stage of registers.
The event register is the only kind of register that can affect the next stage
N O T E
of registers.
The structures of the Operational and Questionable Status Systems are
similar. Figure 4 describe how the Questionable Status Bit (QSB) and the
Operational Status Bit (OSB) of the Status Byte Register are determined.

Figure 3 The Registers and Filters for a Node

Enable Registers
OR
Event Registers
A positive transition in the condition
register, when a bit changes from 0 → 1,
1 1 1 1 1
causes the corresponding bit of the
corresponding event register
to change from 0 → 1.
Condition Registers
Introduction to Programming
To the
Condition Register
of the Next Node
33