EP2C20F256C8N Datasheet, PDF (83/470 Pages) Altera Corporation – Cyclone II Device Handbook, Volume 1

Cyclone II Architecture
I/O Banks
The I/O pins on Cyclone II devices are grouped together into I/O banks
and each bank has a separate power bus. EP2C5 and EP2C8 devices have
four I/O banks (see Figure 2–28), while EP2C15, EP2C20, EP2C35,
EP2C50, and EP2C70 devices have eight I/O banks (see Figure 2–29).
Each device I/O pin is associated with one I/O bank. To accommodate
voltage-referenced I/O standards, each Cyclone II I/O bank has a VREF
bus. Each bank in EP2C5, EP2C8, EP2C15, EP2C20, EP2C35, and EP2C50
devices supports two VREF pins and each bank of EP2C70 supports four
VREF pins. When using the VREF pins, each VREF pin must be properly
connected to the appropriate voltage level. In the event these pins are not
used as VREF pins, they may be used as regular I/O pins.
The top and bottom I/O banks (banks 2 and 4 in EP2C5 and EP2C8
devices and banks 3, 4, 7, and 8 in EP2C15, EP2C20, EP2C35, EP2C50, and
EP2C70 devices) support all I/O standards listed in Table 2–17, except the
PCI/PCI-X I/O standards. The left and right side I/O banks (banks 1 and
3 in EP2C5 and EP2C8 devices and banks 1, 2, 5, and 6 in EP2C15, EP2C20,
EP2C35, EP2C50, and EP2C70 devices) support I/O standards listed in
Table 2–17, except SSTL-18 class II, HSTL-18 class II, and HSTL-15 class II
I/O standards. See Table 2–17 for a complete list of supported I/O
standards.
The top and bottom I/O banks (banks 2 and 4 in EP2C5 and EP2C8
devices and banks 3, 4, 7, and 8 in EP2C15, EP2C20, EP2C35, EP2C50, and
EP2C70 devices) support DDR2 memory up to 167 MHz/333 Mbps and
QDR memory up to 167 MHz/668 Mbps. The left and right side I/O
banks (1 and 3 of EP2C5 and EP2C8 devices and 1, 2, 5, and 6 of EP2C15,
EP2C20, EP2C35, EP2C50, and EP2C70 devices) only support SDR and
DDR SDRAM interfaces. All the I/O banks of the Cyclone II devices
support SDR memory up to 167 MHz/167 Mbps and DDR memory up to
167 MHz/333 Mbps.
1 DDR2 and QDRII interfaces may be implemented in Cyclone II
side banks if the use of class I I/O standard is acceptable.
Altera Corporation
February 2007
2–57
Cyclone II Device Handbook, Volume 1