M1AFS250-FGG256I Actel Corporation, M1AFS250-FGG256I Datasheet - Page 168

• Manufacturer Part Number: M1AFS250-FGG256I
• Description: Actel Fusion Family Of Mixed Signal Fpgas
• Manufacturer: Actel Corporation

Device Architecture
Figure 2-108 • Example of Implementation of Skew Circuits in Bidirectional Transmission Systems Using
Figure 2-109 • Timing Diagram (bypasses skew circuit)
2- 15 2
Skew or
Bypass
Skew
Transmitter 1: OFF
Transmitter 2: ON
ENABLE(t1)
Transmitter 1: Fusion I/O
At the system level, the skew circuit can be used in applications where transmission activities on
bidirectional data lines need to be coordinated. This circuit, when selected, provides a timing margin that
can prevent bus contention and subsequent data loss or transmitter overstress due to transmitter-to-
transmitter current shorts.
bidirectional communication system.
110 on page 2-153
Fusion Devices
ENABLE (t2)
ENABLE (r1)
ENABLE (t1)
EN(r1)
EN (b1)
EN (b2)
Delay (t1)
Routing
shows how it can be avoided with the skew circuit.
EN(b1)
Contention
Figure 2-108
Bus
Transmitter 1: ON
Bidirectional Data Bus
Transmitter
ENABLE/
DISABLE
Figure 2-109
presents an example of the skew circuit implementation in a
Transmitter 2: OFF
R e visio n 1
shows how bus contention is created, and
EN(b2)
Transmitter 2: Generic I/O
Transmitter 1: OFF
Delay (t2)
Routing
ENABLE(t2)
Figure 2-