Figure 7-7: Multiple Device AS Configuration When Both Devices in the Chain Receive Different Sets of
Configuration Data
DATA
DCLK
nCS
ASDI
EPCS or EPCQ Device
FPGA Device Master
FPGA Device Slave
GND
nCE
nCEO
nSTATUS
CONF_DONE
DATA0
DCLK
nCEO
nSTATUS
CONF_DONE
10 kΩ
nCONFIG
nCONFIG
nCE
Buffers
MSEL [4..0]
AS_DATA1
DCLK
nCSO
ASDO
V
CCPGM
MSEL[4..0]
CLKUSR
V
CCPGM
V
CCPGM
10 kΩ
10 kΩ
Connect the pull-up resistors to
V
CCPGM
at a 3.0- or 3.3-V power
supply.
Connect the repeater buffers between the
FPGA master and slave device for AS_DATA1
or DATA0 and DCLK for every fourth device.
You can leave the nCEO pin
unconnected or use it as a user I/O
pin when it does not feed another
device’s nCE pin.
For the appropriate MSEL settings
based on POR delay settings, set the
slave device MSEL setting to the PS
scheme.
For more information, refer to the
MSEL pin settings.
Use the CLKUSR pin to supply the
external clock source to drive DCLK
during configuration.
10 kΩ
V
CCPGM
When a device completes configuration, its
nCEO
pin is released low to activate the
nCE
pin of the next device
in the chain. Configuration automatically begins for the second device in one clock cycle.
Estimating the Active Serial Configuration Time
The AS configuration time is mostly the time it takes to transfer the configuration data from an EPCS or
EPCQ device to the Cyclone V device.
Use the following equations to estimate the configuration time:
• AS x1 mode
.rbf Size x (minimum
DCLK
period / 1 bit per
DCLK
cycle) = estimated minimum configuration time.
• AS x4 mode
.rbf Size x (minimum
DCLK
period / 4 bits per
DCLK
cycle) = estimated minimum configuration time.
Compressing the configuration data reduces the configuration time. The amount of reduction varies depending
on your design.
Using EPCS and EPCQ Devices
EPCS devices support AS x1 mode and EPCQ devices support AS x1 and AS x4 modes.
Altera Corporation
Configuration, Design Security, and Remote System Upgrades in Cyclone V Devices
7-15
Estimating the Active Serial Configuration Time
CV-52007
2014.01.10