Configuration & Testing
For Stratix, the CRC is computed by the Quartus II software and
downloaded into the device as a part of the configuration bit stream. The
CRC_ERRORpin reports a soft error when configuration SRAM data is
corrupted, triggering device reconfiguration.
Custom-Built Circuitry
Dedicated circuitry is built in the Stratix devices to perform error
detection automatically. You can use the built-in dedicated circuitry for
error detection using CRC feature in Stratix devices, eliminating the need
for external logic. This circuitry will perform error detection
automatically when enabled. This error detection circuitry in Stratix
devices constantly checks for errors in the configuration SRAM cells
while the device is in user mode. You can monitor one external pin for the
error and use it to trigger a re-configuration cycle. Select the desired time
between checks by adjusting a built-in clock divider.
Software Interface
In the Quartus II software version 4.1 and later, you can turn on the
automated error detection CRC feature in the Device & Pin Options
dialog box. This dialog box allows you to enable the feature and set the
internal frequency of the CRC between 400 kHz to 100 MHz. This controls
the rate that the CRC circuitry verifies the internal configuration SRAM
bits in the FPGA device.
For more information on CRC, see AN 357: Error Detection Using CRC in
Altera FPGA Devices.
Stratix devices include a diode-connected transistor for use as a
temperature sensor in power management. This diode is used with an
external digital thermometer device such as a MAX1617A or MAX1619
from MAXIM Integrated Products. These devices steer bias current
through the Stratix diode, measuring forward voltage and converting this
reading to temperature in the form of an 8-bit signed number (7 bits plus
sign). The external device’s output represents the junction temperature of
the Stratix device and can be used for intelligent power management.
Temperature
Sensing Diode
The diode requires two pins (tempdiodepand tempdioden) on the
Stratix device to connect to the external temperature-sensing device, as
shown in Figure 3–5. The temperature sensing diode is a passive element
and therefore can be used before the Stratix device is powered.
Altera Corporation
July 2005
3–13
Stratix Device Handbook, Volume 1
ALTERA [ ALTERA CORPORATION ]
