Information Technology Reference
In-Depth Information
•
The bus arbitrator broadcasting a question frame for the required parameter, in a time that
is used not used for periodic traffic. Next the producer of the parameter responds with
the parameter and sets an aperiodic request bit in the control field of the response frame
(RQ). Aperiodic transfers have the two priority levels of urgent or normal.
•
The bus arbitrator sending an identification request frame (ID_RQ) to ask the producer of
the required parameter to transmit its request. The producer of the parameter responds
with an RP_RQ frame. This frame contains a list of identifiers (between 1 and 64
identifier).
20.4 Exercises
20.4.1
In WorldFIP, Manchester coding is used as a line code. How does this code the
bits:
(a)
0 is a positive voltage, 1 is a negative voltage
(b)
0 is a negative voltage, 1 is a positive voltage
(c)
0 is a transition from low to high, 1 is a transition from high to low
(d)
0 is a zero voltage, 1 is a positive voltage
20.4.2
In WorldFIP, what is defined as a bit volition over a single bit period:
(a)
A constant low or a constant high voltage level:
(b)
A change from low to high voltage
(c)
A change from high to low voltage
(d)
A transition which is the same as the previous transition
20.4.3
How is the start and end of a frame determined in WorldFIP:
(a)
They are a constant voltage level
(b)
They contain violations
(c)
They contain no violations
(d)
They contain no transitions
20.4.4
What is the purpose of the preamble in WorldFIP:
(a)
It reduces power dissipation
(b)
It allows all the connected devices to synchronise their receiving clocks
(c)
It increases the bit rate
(d)
It contain information
20.4.5
Discuss how parameters on a WorldFIP network can be assigned a unique ID.
What is the maximum number of IDs that can be allocated. Also, what is the
maximum number of devices that can be connected to a WorldFIP network.
20.4.6
Outline the main method that WorldFIP uses to request and broadcast data on the
network.
