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DS3134
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Signal Name:
PSTOP*
Signal Description:
PCI Stop
Signal Type:
Input / Output (tri-state capable)
This active low signal is created by the target to signal to the initiator that it requests the initiator stop the
current bus transaction. When the device is a target, this signal is an output and is updated on the rising
edge of PCLK. When the device is an initiator, this signal is input and is sampled on the rising edge of
PCLK. When the device is not involved in a bus transaction, PSTOP* is tri-stated.
Signal Name:
PIDSEL
Signal Description:
PCI Initialization Device Select
Signal Type:
Input
This input signal is used as a chip select during configuration read and writes transactions. This signal is
disabled when the Local Bus is set in the Configuration Mode (LMS = 1). When PIDSEL is set high
during the address phase of a bus transaction and the Bus Command signals (PCBE0 to PCBE3) indicate
a register read or write, then the device allows access to the PCI configuration registers and the
PDEVSEL* signal is asserted during the PCLK cycle. PIDSEL is sampled on the rising edge of PCLK.
Signal Name:
PDEVSEL*
Signal Description:
PCI Device Select
Signal Type:
Input / Output (tri-state capable)
This active low signal is created by the target when it has decoded the address sent to it by the initiator, as
it's own to indicate that that the address is valid. If the device is an initiator and does not see the signal
asserted within six PCLK cycles, then the bus transaction is aborted and the PCI Host is alerted. When the
device is a target, this signal is an output and is updated on the rising edge of PCLK. When the device is
an initiator, this signal is input and is sampled on the rising edge of PCLK. When the device is not
involved in a bus transaction, PDEVSEL* is tri-stated.
Signal Name:
PREQ*
Signal Description:
PCI Bus Request
Signal Type:
Output (tri-state capable)
This active low signal is asserted by the initiator to request that the PCI bus arbiter allow it access to the
bus. PREQ* is updated on the rising edge of PCLK.
Signal Name:
PGNT*
Signal Description:
PCI Bus Grant
Signal Type:
Input
This active low signal is asserted by the PCI bus arbiter to indicate to the PCI requesting agent that access
to the PCI bus has been granted. The device samples PGNT* on the rising edge of PCLK and if detected,
will initiate a bus transaction when it has sensed that the PFRAME* signal has been deasserted.
Signal Name:
PPERR*
Signal Description:
PCI Parity Error
Signal Type:
Input / Output (tri-state capable)
This active low signal reports parity errors that occur. PPERR* can be enabled and disabled via the PCI
Configuration Registers. This signal is updated on the rising edge of PCLK.