I/O Structures in IGLOOe and ProASIC3E Devices

30

v1.4

I/O Software Support

In Actel's Libero IDE software, default settings have been defined for the various I/O standards

supported. Changes can be made to the default settings via the use of attributes; however, not all

I/O attributes are applicable for all I/O standards. Table 16 lists the valid I/O attributes that can be

manipulated by the user for each I/O standard.

Single-ended I/O standards in low-power flash devices support up to five different drive

strengths.

Table 17 on page 31 lists the default values for the above selectable I/O attributes as well as those

that are preset for each I/O standard.

Refer to Table 16 for SLEW and OUT_DRIVE settings. Table 18 on page 32 lists the voltages for the

supported I/O standards.

Table 16 • IGLOOe and ProASIC3E I/O Attributes vs. I/O Standard Applications

I/O Standard

LVTTL/LVCMOS 3.3 V

✓✓

✓✓✓

✓✓

✓✓✓

LVCMOS 2.5 V

✓✓

✓✓✓

✓✓

✓✓✓

LVCMOS 2.5/5.0 V

✓✓

✓✓✓

✓✓

✓✓✓

LVCMOS 1.8 V

✓✓

✓✓✓

✓✓

✓✓✓

LVCMOS 1.5 V

✓✓

✓✓✓

✓✓

✓✓✓

PCI (3.3 V)

✓✓

✓

✓

✓

PCI-X (3.3 V)

✓

✓

✓✓

✓✓

GTL+ (3.3 V)

✓✓

✓

✓

✓✓

GTL+ (2.5 V)

✓✓

✓

✓

✓✓

GTL (3.3 V)

✓✓

✓

✓

✓✓

GTL (2.5 V)

✓✓

✓

✓

✓✓

HSTL Class I

✓✓

✓

✓

✓✓

HSTL Class II

✓✓

✓

✓

✓✓

SSTL2 Class I and II

✓✓

✓

✓

✓✓

SSTL3 Class I and II

✓✓

✓

✓

✓✓

LVDS, B-LVDS, M-LVDS

✓✓

✓

✓

✓

LVPECL

✓✓

✓

✓