EPF8452ATC100-4N Datasheet, PDF (53/62 Pages) Altera Corporation – Programmable Logic Device Family

FLEX 8000 Programmable Logic Device Family Data Sheet
Operating Modes
The FLEX 8000 architecture uses SRAM elements that require
configuration data to be loaded whenever the device powers up and
begins operation. The process of physically loading the SRAM
programming data into the device is called configuration. During
initialization, which occurs immediately after configuration, the device
resets registers, enables I/O pins, and begins to operate as a logic device.
The I/O pins are tri-stated during power-up, and before and during
configuration. The configuration and initialization processes together are
called command mode; normal device operation is called user mode.
SRAM elements allow FLEX 8000 devices to be reconfigured in-circuit
with new programming data that is loaded into the device. Real-time
reconfiguration is performed by forcing the device into command mode
with a device pin, loading different programming data, reinitializing the
device, and resuming user-mode operation. The entire reconfiguration
process requires less than 100 ms and can be used to dynamically
reconfigure an entire system. In-field upgrades can be performed by
distributing new configuration files.
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Configuration Schemes
The configuration data for a FLEX 8000 device can be loaded with one of
six configuration schemes, chosen on the basis of the target application.
Both active and passive schemes are available. In the active configuration
schemes, the FLEX 8000 device functions as the controller, directing the
loading operation, controlling external configuration devices, and
completing the loading process. The clock source for all active
configuration schemes is an oscillator on the FLEX 8000 device that
operates between 2 MHz and 6 MHz. In the passive configuration
schemes, an external controller guides the FLEX 8000 device. Table 51
shows the data source for each of the six configuration schemes.
Table 51. Data Source for Configuration
Configuration Scheme
Active serial
Active parallel up
Active parallel down
Passive serial
Passive parallel synchronous
Passive parallel asynchronous
Acronym
Data Source
AS
Altera configuration device
APU Parallel configuration device
APD Parallel configuration device
PS
Serial data path
PPS Intelligent host
PPA Intelligent host
Altera Corporation
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