Transcript Hot Swap Support

Hytec HotSwap
Darrell Nineham
Hytec Electronics Ltd
Provisional Hytec Electronic Ltd
www.hytec-electronics.co.uk
Hotswap Hardware Support
• There is a common
misconception that
the Hotswap
hardware support is
limited to the opto
switch in the
extractor/insertion
handles.
Provisional Hytec Electronic Ltd
www.hytec-electronics.co.uk
Other Hotswap Hardware
• Pre-Charge Voltage (VPC).
• Pre-leading Pins (PLP) on the VME64x
connectors.
• Electro-Static Discharge.
Provisional Hytec Electronic Ltd
www.hytec-electronics.co.uk
Pre-Charge Voltage (VPC) and
Pre-leading Pins (PLP)
• These PLPs are longer than the other pins on
the VME64x connector, allowing them to connect
earlier during insertion.
• This early voltage supply, specifically known as
the Pre-Charge Voltage(VPC), is used as a
power up the carrier card’s Hot Swap Voltage
Controller (SUMMIT IC) and VME Bus buffer IC
(Tri-states).
• The bus is tri-stated actually before its
connected, safe guarding the other IOC cards.
Provisional Hytec Electronic Ltd
www.hytec-electronics.co.uk
Electro-Static Discharge
•
•
•
The carrier cards have a bottom PCB edge is
exposed metal (known as a ‘printed wiring
strip’).
The carrier card front panel has guide pins
both top and bottom to provide additional
discharge sources through the guide pin
sockets in the IOC.
The carrier cards are fitted with 2.2 MegOhms
discharge resistors to provide safe discharge
paths via any of the above drain sources. This
safely discharges the carrier card during any
hot swap.
Provisional Hytec Electronic Ltd
www.hytec-electronics.co.uk
Software Support
• Hytec (particularly Walter Scott, Dave
Brownless and Steve Hunt) choose NOT
to implement hotswap as specified by
Andrew Johnson.
• They have instead modified his drvpac
adding a function ipmCarrierIsPresent().
Provisional Hytec Electronic Ltd
www.hytec-electronics.co.uk