Specifications

9 March 1999 – Subject To Change Functional Description 4–3
21174 Core Logic Chip
4.2 21174 Core Logic Chip
The 21174 core logic chip provides a cost-competitive solution for designers using the
21164 microprocessor to develop uniprocessor systems. The chip provides a 128-bit
memory interface and a PCI I/O interface, and includes the 21174-CA chip packaged
in a 474-pin plastic ball grid array (PBGA).
Figure 4–2 shows the AlphaPC 164LX implementation of the 21174 core logic chip.
Figure 4–2 Main Memory Interface
21164
pc164lx.2
* addr_bus_req
adr_cmd_par
cack
cmd<3:0>
dack
fill
fill_error
fill_id
idle_bc
int4_valid<3:0>
sys_res<1:0>
tag_ctl_par
tag_dirty
victim_pending
21174
memadr_<13:0>
memwe_l
memcas_l<7:0>
memrasb_l<7:0>
memrasa_l<7:0>
miscellaneous
pc164lx.7
Buffers
pc164lx.14-16
bnmemadr<13:0>
bnmemwe_l
addr_h<39:4>
System Control *
data_h<127:0>
data_check_h<15:0>
Quick
Switches
(X16)
pc164lx.9-11
be_<0:2>
pc164lx.12-13
DIMM 3
DIMM 2
DIMM 1
DIMM 0
mem_dat<128:0>
mem_check_h<15:0>
64-Bit PCI
I/O Bus
FM-05946.AI4
bnmemcas_l<7:0>
bnmemrasb_l<7:0>
bnmemrasa_l<7:0>
bnmiscellaneous