I/O Structures in IGLOO and Pro ASIC3 Devices
v1.1
7 - 3
Advanced I/Os—IGLOO, ProASIC3L, and ProASIC3
Table 7-2 and
Table 7-3 show the voltages and compatible I/O standards for IGLOO, ProASIC3L, and
ProASIC3 families.
I/Os provide programmable slew rates (except 30 k gate devices), drive strengths, and weak pull-up
All I/Os are in a known state during power-up, and any power-up sequence is allowed without
current impact. Refer to the "I/O Power-Up and Supply Voltage Thresholds for Power-On Reset
(Commercial and Industrial)" section in the datasheet for more information. During power-up,
before reaching activation levels, the I/O input and output buffers are disabled while the weak
pull-up is enabled. Activation levels are described in the datasheet.
I/O Banks and I/O Standards Compatibility
I/Os are grouped into I/O voltage banks.
Each I/O voltage bank has dedicated I/O supply and ground voltages (VMV/GNDQ for input buffers
and VCCI/GND for output buffers). This isolation is necessary to minimize simultaneous switching
noise from the input and output (SSI and SSO). The switching noise (ground bounce and power
bounce) is generated by the output buffers and transferred into input buffer circuits, and vice
versa. Because of these dedicated supplies, only I/Os with compatible standards can be assigned to
the same I/O voltage bank.
Table 7-3 shows the required voltage compatibility values for each of
these voltages.
There are four I/O banks on the 250 k gate through 1 M gate devices.
There are two I/O banks on the 30 k, 60 k, and 125 k gate devices.
I/O standards are compatible if their VCCI and VMV values are identical. VMV and GNDQ are
"quiet" input power supply pins and are not used on 30 k gate devices (
Table 7-3).
Table 7-2
Supported I/O Standards
IGLOO
AGL030 AGL060 AGL125 AGL250
AGL600
AGL1000
ProASIC3
A3P030 A3P060 A3P125
A3P250/
A3P250L A3P400
A3P600/
A3P600L
A3P1000/
A3P1000L
Single-Ended
LVTTL/LVCMOS 3.3 V,
LVCMOS 2.5 V / 1.8 V / 1.5 V,
LVCMOS 2.5/5.0 V
3.3 V PCI/PCI-X
–
Differential
LVPECL, LVDS, BLVDS,
M-LVDS
–––
Table 7-3
VCCI Voltages and Compatible IGLOO and ProASIC3 Standards
VCCI and VMV (typical)
Compatible Standards
3.3 V
LVTTL/LVCMOS 3.3, PCI 3.3, PCI-X 3.3 LVPECL
2.5 V
LVCMOS 2.5, LVCMOS 2.5/5.0, LVDS, BLVDS, M-LVDS
1.8 V
LVCMOS 1.8
1.5 V
LVCMOS 1.5