CP390
Hotswap
ID 19976, Rev. 0200
Page 4 - 5
®
PEP Modular Computers GmbH
4.2.4
ENUM# Interrupt
The onboard logic generates a low active interrupt signal to indicate that the board is
about to be extracted from the system or inserted into the system.
4.2.5
Hotswap Control and Status Register / Statemachine
All hotswap peripheral boards provide a HotSwap Control And Status Register which
provides information on the current state of the board. The defined bits in this register
set are named:
Due to the fact that no 64-bit transparent PCI-to-PCI bridge currently exists, which
would provide built-in hotswap status registers, another way of implementing these bits
had to be found.
The solution, therefore, is to put this information into the onboard logic.
Since on-chip registers handle read and write accesses in the same way, it is necessary
to exercise care when configuring the PCI-to-PCI GPIOs (general purpose IOs).
Table 4-1: Hotswap Control and Status Register / Statemachine
Bit Name
Function
EXT
Indication of extraction process
INS
Indication of insertion process
LOO
Led on
EIM
ENUM mask bit
Table 4-2: Hotswap Register Bits
Bit Name
Signal on 21150
EXT
GPIO[2]
INS
GPIO[3]
LOO
GPIO[0]
EIM
GPIO[1]
!
Attention!
GPIO[2:3] have to be configured as inputs. A different configura-
tion may damage your bridge device.
