8–6
Chapter 8: Configuration and Remote System Upgrades in Cyclone IV Devices
Configuration
May 2013
Altera Corporation
Configuration Process
This section describes Cyclone IV device configuration requirements and includes the
following topics:
■
■
■
■
“Configuration Error” on page 8–7
■
■
f
For more information about the Altera
®
FPGA configuration cycle state machine, refer
Configuration Handbook
.
Power Up
If the device is powered up from the power-down state, V
CCINT
, V
CCA
, and V
CCIO
(for
the I/O banks in which the configuration and JTAG pins reside) must be powered up
to the appropriate level for the device to exit from POR.
Reset
After power up, Cyclone IV devices go through POR. POR delay depends on the
MSEL
pin settings, which correspond to your configuration scheme. During POR, the device
resets, holds
nSTATUS
and
CONF_DONE
low, and tri-states all user I/O pins (for PS and
FPP configuration schemes only).
1
To tri-state the configuration bus for AS and AP configuration schemes, you must tie
nCE
high and
nCONFIG
low.
The user I/O pins and dual-purpose I/O pins have weak pull-up resistors, which are
always enabled (after POR) before and during configuration. When the device exits
POR, all user I/O pins continue to tri-state. While
nCONFIG
is low, the device is in
reset. When
nCONFIG
goes high, the device exits reset and releases the open-drain
nSTATUS
pin, which is then pulled high by an external 10-k
pull-up resistor. After
nSTATUS
is released, the device is ready to receive configuration data and the
configuration stage starts.
f
For more information about the value of the weak pull-up resistors on the I/O pins
that are on before and during configuration, refer to the
chapter.
Configuration
Configuration data is latched into the Cyclone IV device at each
DCLK
cycle. However,
the width of the data bus and the configuration time taken for each scheme are
different. After the device receives all the configuration data, the device releases the
open-drain
CONF_DONE
pin, which is pulled high by an external 10-k
pull-up resistor.
A low-to-high transition on the
CONF_DONE
pin indicates that the configuration is
complete and initialization of the device can begin.
Summary of Contents for Cyclone IV
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Page 14: ...I 2 Section I Device Core Cyclone IV Device Handbook March 2016 Altera Corporation Volume 1...
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Page 440: ...iv Contents Cyclone IV Device Handbook December 2016 Altera Corporation Volume 3...
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