HC4GX15 Datasheet, PDF (139/668 Pages) Altera Corporation – HardCopy IV Device Handbook

9. Hot Socketing and Power-On Reset in
HardCopy IV Devices
HIV51009-1.0
This chapter contains information about hot-socketing specifications, power-on reset
(POR) requirements, and their implementation in HardCopy^® IV devices.
HardCopy IV devices offer hot socketing, which is also known as hot plug-in or hot
swap, and power sequencing support without the use of any external devices. You
can insert or remove a HardCopy IV device or a board in a system during system
operation without causing undesirable effects to the running system bus or the board
that was inserted into the system.
The hot-socketing feature also removes some of the difficulty when you use
HardCopy IV devices or PCBs that contain a mixture of 3.0-, 2.5-, 1.8-, 1.5-, and 1.2-V
devices. With the HardCopy IV hot-socketing feature, you no longer need to ensure a
proper power-up sequence for each device on the board.
The HardCopy IV hot-socketing feature provides:
■ Board or device insertion and removal without external components or board
manipulation
■ Support for any power-up sequence
■ Non-intrusive I/O buffers to system buses during hot insertion
This chapter also discusses hot-socketing specification, its implementation, and the
POR circuitry in HardCopy IV devices. The POR circuitry keeps the devices in the
reset state until the power supplies are within operating range.
HardCopy IV Hot-Socketing Specifications
HardCopy IV devices are hot-socketing compliant without the need for any external
components or special design requirements. Hot-socketing support in HardCopy IV
devices has the following advantages:
■ You can drive the device before power-up without damaging it.
■ I/O pins remain tri-stated during power-up. The device does not drive out before
or during power-up and does not affect other buses in operation.
■ You can insert or remove a HardCopy IV device from a powered-up system board
without damaging or interfering with normal system and board operation.
Devices Can Be Driven Before Power-Up
You can drive signals into I/O pins, dedicated input pins, and dedicated clock pins of
HardCopy IV devices before or during power-up or power-down without damaging
the device. HardCopy IV devices support power-up or power-down of all power
supplies in any sequence to simplify system level design.
© December 2008 Altera Corporation
HardCopy IV Device Handbook, Volume 1