EP4CE30F29C7N Datasheet, PDF (249/488 Pages) Altera Corporation – Cyclone IV Device Handbook, Volume 1

Chapter 9: SEU Mitigation in Cyclone IV Devices
9–3
Automated SEU Detection
In user mode, Cyclone IV devices support the CHANGE_EDREG JTAG instruction, that
allows you to write to the 32-bit storage register. You can use Jam^™ STAPL files (.jam)
to automate the testing and verification process. You can only execute this instruction
when the device is in user mode, and it is a powerful design feature that enables you
to dynamically verify the CRC functionality in-system without having to reconfigure
the device. You can then use the CRC circuit to check for real errors induced by an
SEU.
Table 9–1 describes the CHANGE_EDREG JTAG instructions.
Table 9–1. CHANGE_EDREG JTAG Instruction
JTAG Instruction
CHANGE_EDREG
Instruction Code
Description
00 0001 0101
This instruction connects the 32-bit CRC storage register between TDI and TDO.
Any precomputed CRC is loaded into the CRC storage register to test the operation
of the error detection CRC circuitry at the CRC_ERROR pin.
1 After the test completes, Altera recommends that you power cycle the device.
Automated SEU Detection
Cyclone IV devices offer on-chip circuitry for automated checking of SEU detection.
Applications that require the device to operate error-free at high elevations or in close
proximity to earth’s north or south pole require periodic checks to ensure continued
data integrity. The error detection cyclic redundancy code feature controlled by the
Device and Pin Options dialog box in the Quartus II software uses a 32-bit CRC
circuit to ensure data reliability and is one of the best options for mitigating SEU.
You can implement the error detection CRC feature with existing circuitry in
Cyclone IV devices, eliminating the need for external logic. The CRC is computed by
the device during configuration and checked against an automatically computed CRC
during normal operation. The CRC_ERROR pin reports a soft error when configuration
CRAM data is corrupted. You must decide whether to reconfigure the FPGA by
strobing the nCONFIG pin low or ignore the error.
CRC_ERROR Pin
A specific CRC_ERROR error detection pin is required to monitor the results of the error
detection circuitry during user mode. Table 9–2 describes the CRC_ERROR pin.
Table 9–2. Cyclone IV Device CRC_ERROR Pin Description
CRC_ERROR Pin Type
Description
I/O, Output (open-drain)
Active high signal indicates that the error detection circuit has detected errors in the
configuration SRAM bits. This pin is optional and is used when the CRC error detection
circuit is enabled in the Quartus II software from the Error Detection CRC tab of the Device
and Pin Options dialog box.
When using this pin, connect it to an external 10-kΩ pull-up resistor to an acceptable
voltage that satisfies the input voltage of the receiving device.
f The CRC_ERROR pin information for Cyclone IV devices is reported in the Cyclone IV
Devices Pin-Outs on the Altera^® website.
May 2013 Altera Corporation
Cyclone IV Device Handbook,
Volume 1