IBM 25CPC710 - Manual (Page 2)

Page 2 of 8 Version 1.0 11/08/01
Processor Interface:
v Voltage Level and Bus Speed Differences
Ø The CPC710 DD3.x revision supports 60x bus operation at speeds of up to 133MHz, at
an I/O voltage of 2.5V. This interface voltage level is supported on the PPC750L, 750CX,
and 750CXe processors.
This is a change from the previous revision.
v I/O Signal New Functionality
Ø Set bit 18 of 60x Bus Arbiter register (system register CPC0_ABCNTL) to 1 to allow the
signal level of SYS_TA_ to be confirmed and held at a high logic level (after precharging)
as soon as the CPC710 DD3.x exits the RESET state. This is to allow for proper
operation in systems with high loads on the CPU bus.
v I/O Signal Additional Functionality for 4-way Processor Support
Ø
Coming out of reset, the 60x bus arbitration logic of the CPC710 DD3.x defaults to the
same dual processor mode used in the CPC710 DD2. To enable 4-way arbitration, the
Master CPU should set chip control register CPC0_ABCNTL [17] to a “1”. Then the
SYS_HRESET2_, SYS_HRESET3_, SYS_SRESET2_ and SYS_SRESET3_ signals will
go inactive, allowing CPUs 2 and 3 to exit the reset state.
Ø The two Reset registers CPC0_RSTR and CPC0_SRST have been modified to include
bits to support program control operation of hard and soft reset signals for the additional
processors.
§ Connectivity Reset Register bits CPC0_RSTR [4:5] controls signals SYS_HRESET2_
and SYS_HRESET3_ respectively. CPU Soft Reset Register bits CPC0_SRST [4:5]
controls signals SYS_SRESET2_ and SYS_SRESET3_ respectively
§ The CPC0_PIDR Register has been modified to allow identification of each of the 4
processors; if CPC0_PIDR [24:31] is read as 'h00’ it indicates the Processor
corresponding to BR0_/BG0_ is active. Valid values for these bits are:
•
= 0x00==> Processor corresponding to BR0_/BG0_
•
= 0x01 ==> Processor corresponding to BR1_/BG1_
•
= 0x02 ==> Processor corresponding to BR2_/BG2_
•
= 0x03 ==> Processor corresponding to BR3_/BG3_
v I/O Signals for 4-way Processor Support
Ø
The signals SYS_MCP0: 3 are used to indicate to the CPUs that the CPC710 has
detected an error condition and a machine check is required. To help reduce pin count,
output signals SYS_MCP2_ and SYS_MCP0_ are generated from one internal signal
source. SYS_MCP3_ and SYS_MCP1_ also share a common internal signal source.
Ø
The System Error Status Register has not been modified and only errors that occur with
Processor 0 or 1 can be detected and reported.