Power-On Reset Circuitry
For Cyclone II devices, wake-up time consists of power-up, POR,
configuration, and initialization. The device must properly go through all
four stages to configure correctly and begin operation. You can calculate
wake-up time using the following equation:
Wake-Up Time = V Ramp Time + POR Time + Configuration Time + Initialization Time
CC
Figure 4–3 illustrates the components of wake up time.
Figure 4–3. Cyclone II Wake-Up Time
Voltage
V
Minimum
CC
Time
V
Ramp
CC
Time
POR Time
Configuration Time
Initialization
Time
User
Mode
Note to Figure 4–3:
(1) VCC ramp must be monotonic.
The VCC ramp time and POR time will depend on the device
characteristics and the power supply used in your system. The fast-on
devices require a maximum VCC ramp time of 2 ms and have a maximum
POR time of 12 ms.
Configuration time will depend on the configuration mode chosen and
the configuration file size. You can calculate configuration time by
multiplying the number of bits in the configuration file with the period of
the configuration clock. For fast configuration times, you should use
Passive Serial (PS) configuration mode with maximum DCLK frequency
of 100 MHz. In addition, you can use compression to reduce the
configuration file size and speed up the configuration time. The tCD2UM
or tCD2UMC parameters will determine the initialization time.
1
For more information on the tCD2UM or tCD2UMC parameters, refer
to the Configuring Cyclone II Devices chapter in the Cyclone II
Device Handbook.
4–6
Cyclone II Device Handbook, Volume 1
Altera Corporation
February 2007
ALTERA [ ALTERA CORPORATION ]
