2. PCI Interface
51
PowerSpan II User Manual
80A1010_MA001_09
Integrated Device Technology
www.idt.com
The PowerSpan II PCI Master generates a Memory Read command selection according to the rules in
The read amount presented to the PCI Master determines the command used. A Memory Read Line
command uses the burst length programmed into the CLINE[7:0] field in the
. It is programmable to 16-, 32-, 64-, or 128 bytes.
2.3.3.3
Parity Monitoring and Generation
PowerSpan II monitors Px_PAR#/Px_PAR64# when it accepts data as a PCI master during a read, and
drives Px_PAR#/Px_PAR64# when it provides data as a PCI master during a write. PowerSpan II also
drives Px_PAR#/Px_PAR64# during the address phase of a transaction when it is a PCI master. In both
address and data phases, the Px_PAR#/Px_PAR64# signal provides even parity for Px_C/BE#[3:0] and
Px_AD[31:0]. Even parity is enabled Px_C/BE#[7:4] and Px_AD[63:32] for PCI-1 in 64-bit mode.
PowerSpan II parity response is enabled through the Parity Error Response (PERESP) bit in the
Control and Status Register.” on page 251
. Data parity errors are reported through the assertion of
Px_PERR# when the PERESP bit is set. The Detected Parity Error (D_PE) bit in the
and Status Register.” on page 251
is set when PowerSpan II encounters a parity error as a PCI master
on any transaction. PowerSpan II records an error condition in the event of a parity error (see
).
The Master Data Parity Detected (MDP_D) bit in the
“PCI-1 Control and Status Register.” on page 251
is set if the PERESP bit is enabled and either PowerSpan II is the master of the transaction where it
asserts PERR#, or the addressed target asserts PERR#. If the transfer originated from the Processor
Interface, then PowerSpan II sets the MDP_D bit and the Px_PB_ERR_EN bit in the
. PowerSpan II then asserts an interrupt (see
).
Table 9: PowerSpan II PCI Master Read Commands
Internal Request of Transaction
Length
PCI Memory Read Command
<= 8 bytes
Memory Read
<= CLINE[7:0] in Px_MISC0
Memory Read Line
> CLINE[7:0] in Px_MISC0
Memory Read Multiple
If the PCI Master does not complete the burst read transaction before a target termination, it
completes the read with subsequent PCI read transactions at the appropriate address.
PowerSpan II continues with the transaction independent of any parity errors reported during
the transaction.