afs600 Actel Corporation, afs600 Datasheet - Page 150

• Manufacturer Part Number: afs600
• Description: Actel Fusion Programmable System Chips Mixed-signal Family With Optional Arm Support
• Manufacturer: Actel Corporation

Figure 2-104 • Timing Diagram (with skew circuit selected)
Weak Pull-Up and Weak Pull-Down
Resistors
Fusion devices support optional weak pull-up and pull-
down resistors for each I/O pin. When the I/O is pulled
up, it is connected to the V
bank. When it is pulled down, it is connected to GND.
Refer to
Slew Rate Control and Drive Strength
Fusion devices support output slew rate control: high
and low. The high slew rate option is recommended to
minimize the propagation delay. This high-speed option
may introduce noise into the system if appropriate signal
integrity measures are not adopted. Selecting a low slew
rate reduces this kind of noise but adds some delays in
the system. Low slew rate is recommended when bus
transients are expected. Drive strength should also be
selected according to the design requirements and noise
immunity of the system.
2 -1 3 6
Actel Fusion Programmable System Chips
Table 2-94 on page 2-157
Transmitter 1: OFF
Transmitter 2: ON
ENABLE (t2)
ENABLE (t1)
EN (b1)
EN (b2)
CCI
of its corresponding I/O
for more information.
Result: No Bus Contention
A d v a n c e d v 1 . 4
Transmitter 1: ON
Transmitter 2: OFF
The output slew rate and multiple drive strength
controls are available in LVTTL/LVCMOS 3.3 V, LVCMOS
2.5 V, LVCMOS 2.5 V / 5.0 V input, LVCMOS 1.8 V, and
LVCMOS 1.5 V. All other I/O standards have a high output
slew rate by default.
For Fusion slew rate and drive strength specifications,
refer to the appropriate I/O bank table:
Table 2-79 on page 2-139
above selectable I/O attributes as well as those that are
preset for each I/O standard.
Refer to
page 2-137
on page 2-138
on page 2-139
standards.
• Fusion Standard I/O
• Fusion Advanced I/O
• Fusion Pro I/O
Table
for SLEW and OUT_DRIVE settings.
lists the I/O default attributes.
lists the voltages for the supported I/O
2-75,
(Table 2-77 on page
Transmitter 1: OFF
Table
lists the default values for the
(Table 2-75 on page
(Table 2-76 on page
2-76, and
2-137)
Table 2-77 on
Table 2-78
Table 2-79
2-137)
2-137)