![Altera Cyclone IV Device Handbook Download Page 199](http://html1.mh-extra.com/html/altera/cyclone-iv/cyclone-iv_device-handbook_2910785199.webp)
Chapter 8: Configuration and Remote System Upgrades in Cyclone IV Devices
8–35
Configuration
May 2013
Altera Corporation
After the first device completes configuration in a multi-device configuration chain,
its
nCEO
pin drives low to activate the
nCE
pin of the second device, which prompts the
second device to begin configuration. The second device in the chain begins
configuration in one clock cycle. Therefore, the transfer of data destinations is
transparent to the external host device.
nCONFIG
,
nSTATUS
,
DCLK
,
DATA[0]
, and
CONF_DONE
configuration pins are connected to every device in the chain. To ensure
signal integrity and prevent clock skew problems, configuration signals may require
buffering. Ensure that
DCLK
and
DATA
lines are buffered. All devices initialize and enter
user mode at the same time because all
CONF_DONE
pins are tied together.
If any device detects an error, configuration stops for the entire chain and you must
reconfigure the entire chain because all
nSTATUS
and
CONF_DONE
pins are tied together.
For example, if the first device flags an error on
nSTATUS
, it resets the chain by pulling
its
nSTATUS
pin low. This behavior is similar to a single device detecting an error.
You can have multiple devices that contain the same configuration data in your
system. To support this configuration scheme, all device
nCE
inputs are tied to GND,
while the
nCEO
pins are left floating.
nCONFIG
,
nSTATUS
,
DCLK
,
DATA[0]
, and
CONF_DONE
configuration pins are connected to every device in the chain. To ensure signal
integrity and prevent clock skew problems, configuration signals may require
buffering. Ensure that the
DCLK
and
DATA
lines are buffered. Devices must be of the
same density and package. All devices start and complete configuration at the same
time.
shows a multi-device PS configuration when both Cyclone IV devices are
receiving the same configuration data.
Figure 8–15. Multi-Device PS Configuration When Both Devices Receive the Same Data
Notes to
(1) You must connect the pull-up resistor to a supply that provides an acceptable input signal for all devices in the chain.
V
CC
must be high enough to meet the V
IH
specification of the I/O on the device and the external host.
(2) The
nCEO
pins of both devices are left unconnected or used as user I/O pins when configuring the same configuration
data into multiple devices.
(3) The
MSEL
pin settings vary for different configuration voltage standards and POR time. To connect the
MSEL
pins,
, and
. Connect the
MSEL
pins directly
to V
CCA
or GND.
(4) All I/O inputs must maintain a maximum AC voltage of 4.1 V.
DATA[0]
and
DCLK
must fit the maximum overshoot
outlined in
External Host
(MAX II Device or
Microprocessor)
Memory
ADDR
Cyclone IV Master Device
nSTATUS
CONF_DONE
nCE
nCEO
DATA[0]
GND
MSEL[ ]
DATA[0]
(4)
nCONFIG
DCLK
(4)
nSTATUS
CONF_DONE
nCE
nCEO
N.C. (2)
DATA[0]
(4)
nCONFIG
DCLK
(4)
Cyclone IV Slave Device
N.C. (2)
GND
(3)
MSEL[ ]
(3)
Buffers (4)
10 k
V
CCIO
(1)
V
CCIO
(1)
10 k
Summary of Contents for Cyclone IV
Page 10: ...x Chapter Revision Dates Cyclone IV Device Handbook March 2016 Altera Corporation Volume 1...
Page 14: ...I 2 Section I Device Core Cyclone IV Device Handbook March 2016 Altera Corporation Volume 1...
Page 274: ...vi Contents Cyclone IV Device Handbook February 2015 Altera Corporation Volume 2...
Page 440: ...iv Contents Cyclone IV Device Handbook December 2016 Altera Corporation Volume 3...
Page 442: ...vi Chapter Revision Dates Cyclone IV Device Handbook December 2016 Altera Corporation Volume 3...
Page 446: ......