EP4CE55F23C7 Altera, EP4CE55F23C7 Datasheet - Page 112

• Manufacturer Part Number: EP4CE55F23C7
• Description: IC CYCLONE IV FPGA 55K 484FBGA
• Manufacturer: Altera
• Series: CYCLONE® IV Er

Specifications of EP4CE55F23C7

• Number Of Logic Elements/cells: 55856
• Number Of Labs/clbs: 3491
• Total Ram Bits: 2340000
• Number Of I /o: 324
• Voltage - Supply: 1.15 V ~ 1.25 V
• Mounting Type: Surface Mount
• Operating Temperature: 0°C ~ 85°C
• Package / Case: 484-FBGA
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Number Of Gates: -

6–4
Bus Hold
Programmable Pull-Up Resistor
Programmable Delay
Cyclone IV Device Handbook, Volume 1
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Each Cyclone IV device user I/O pin provides an optional bus-hold feature. The
bus-hold circuitry holds the signal on an I/O pin at its last-driven state. Because the
bus-hold feature holds the last-driven state of the pin until the next input signal is
present, an external pull-up or pull-down resistor is not necessary to hold a signal
level when the bus is tri-stated.
The bus-hold circuitry also pulls undriven pins away from the input threshold
voltage in which noise can cause unintended high-frequency switching. You can select
this feature individually for each I/O pin. The bus-hold output drives no higher than
V
If you enable the bus-hold feature, the device cannot use the programmable pull-up
option. Disable the bus-hold feature when the I/O pin is configured for differential
signals. Bus-hold circuitry is not available on dedicated clock pins.
Bus-hold circuitry is only active after configuration. When going into user mode, the
bus-hold circuit captures the value on the pin present at the end of configuration.
For the specific sustaining current for each V
resistor and for the overdrive current used to identify the next driven input level, refer
to the
Each Cyclone IV device I/O pin provides an optional programmable pull-up resistor
while in user mode. If you enable this feature for an I/O pin, the pull-up resistor
holds the output to the V
If you enable the programmable pull-up resistor, the device cannot use the bus-hold
feature. Programmable pull-up resistors are not supported on the dedicated
configuration, JTAG, and dedicated clock pins.
When the optional DEV_OE signal drives low, all I/O pins remains tri-stated even
with the programmable pull-up option enabled.
The Cyclone IV IOE includes programmable delays to ensure zero hold times,
minimize setup times, increase clock-to-output times, and delay the clock input
signal.
A path in which a pin directly drives a register may require a programmable delay to
ensure zero hold time, whereas a path in which a pin drives a register through
combinational logic may not require the delay. Programmable delays minimize setup
time. The Quartus II Compiler can program these delays to automatically minimize
setup time while providing a zero hold time. Programmable delays can increase the
register-to-pin delays for output registers. Each dual-purpose clock input pin
provides a programmable delay to the global clock networks.
CCIO
to prevent overdriving signals.
Cyclone IV Device Datasheet
CCIO
level of the output pin’s bank.
chapter.
CCIO
voltage level driven through the
Chapter 6: I/O Features in Cyclone IV Devices
© December 2010 Altera Corporation
I/O Element Features