HC4GX15 Datasheet, PDF (458/668 Pages) Altera Corporation – HardCopy IV Device Handbook

1–194
Chapter 1: HardCopy IV GX Transceiver Architecture
Document Revision History
You must connect a separate 2 kΩ (tolerance max ± 1%) external resistor on each RREF
pin in the HardCopy IV GX device to ground. To ensure proper operation of the
calibration block, the RREF resistor connection in the board must be free from external
noise.
Input Signals to the Calibration Block
Figure 1–164 shows the required inputs to the calibration block. The ALTGX
MegaWizard Plug-In Manager provides the cal_blk_clk and
cal_blk_powerdown ports to control the calibration block.
Figure 1–164. Input Signals to the Calibration Blocks
RREF pin
cal_blk_clk
cal_blk_powerdown
Calibration Block
Internal
Reference
Voltage
Generator
Reference
Signal
OCT Calibration
Control
OCT Calibration
Circuit
Analog Block
Calibration Circuit
Analog Block
Calibration Control
■ cal_blk_clk—you must use the cal_blk_clk port to provide input clock to
the calibration clock. The frequency of cal_blk_clk must be within 10 MHz to
125 MHz (this range is preliminary. Final values will be available upon
characterization). You can use dedicated clock routes such as the global or regional
clock. If you do not have suitable input reference clock or dedicated clock routing
resources available, use divide-down logic from the core fabric to generate a slow
clock and use local clocking routing. Drive the cal_blk_clk port of all ALTGX
instances that are associated with the same calibration block from the same input
pin or logic.
■ cal_blk_powerdown—you can perform calibration multiple times by using the
cal_blk_powerdown port available through the ALTGX MegaWizard Plug-In
Manager. Assert this signal for approximately 500 ns (this is preliminary. Final
values will be available upon characterization). Following de-assertion of
cal_blk_powerdown, the calibration block restarts the calibration process. Drive
the cal_blk_powerdown port of all ALTGX instances that are associated with
the same calibration block from the same input pin or logic.
Document Revision History
Table 1–55 shows the revision history for this chapter.
Table 1–55. Document Revision History
Date and Document Version
June 2009, v1.0
Initial release.
Changes Made
Summary of Changes
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HardCopy IV Device Handbook Volume 3
© June 2009 Altera Corporation