13–10
Altera Corporation
Stratix II GX Device Handbook, Volume 2
October 2007
Configuration Features
VCCPD Pins
Stratix II and Stratix II GX devices also offer a new power supply, VCCPD,
which must be connected to 3.3-V in order to power the 3.3-V/2.5-V
buffer available on the configuration input pins and JTAG pins. VCCPD
applies to all the JTAG input pins (TCK, TMS, TDI, and TRST) and the
configuration pins when VCCSEL is connected to ground. Refer to
Table 13–5 for information on the pins affected by VCCSEL.
1
VCCPD must ramp-up from 0-V to 3.3-V within 100 ms. If VCCPD
is not ramped up within this specified time, your Stratix II or
Stratix II GX device will not configure successfully. If your
system does not allow for a VCCPD ramp-up time of 100 ms or
less, you must hold nCONFIG low until all power supplies are
stable.
VCCSEL Pin
The VCCSEL pin selects the type of input buffer used on configuration
input pins and it selects the POR trip point voltage level for VCCIO bank 3
powered by VCCIO3 pins.
1
The configuration input pins and the PLL_ENA pin (
Table 13–5) have a
dual buffer design. These pins have a 3.3-V/2.5-V input buffer and a
1.8-V/1.5-V input buffer. The VCCSEL input pin selects which input
buffer is used during configuration. The 3.3-V/2.5-V input buffer is
powered by VCCPD, while the 1.8-V/1.5-V input buffer is powered by
VCCIO. After configuration, the dual-purpose configuration pins are
powered by the VCCIO pins of the bank in which they reside. Table 13–5 shows the pins affected by VCCSEL.