21285-AB Sdram And Rom Operation - Intel Corporation

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21285-AB

Manufacturer Part Number
21285-AB
Description
Microprocessor, 21285 Core Logic For SA-110 Microprocessor
Manufacturer
Intel Corporation
Datasheet

Specifications of 21285-AB

Case
BGA
Dc
99+/00+

SDRAM and ROM Operation

This chapter describes the operation of the SDRAM and ROM.
4.1
SDRAM Control
The SDRAM controller on the 21285 controls from one to four arrays of synchronous DRAMs
(SDRAMs). SDRAM supported parts include: 8Mb, 16Mb, and 64Mb.
All SDRAMs share command and address bits, but have separate clock and chip select bits (see
Figure
4-1).
Figure 4-1. SDRAM Configuration
D[31:0]
SA-110
Note:
When SA-110 reads or writes SDRAM,
the data does not pass through 21285.
SDRAM operations performed by the 21285 are refresh, read, write, and mode register set. Reads
and writes are generated by either the SA-110, PCI bus masters (including I
channels.
21285 Core Logic for SA-110 Datasheet
SDRAM
A
Optional
Transceiver
OE
B
21285
4
sdclk [3:0]
cs_l [3:0]
cmd [2:0]
ma [12:0]
ba [1:0]
d_wren_l
FM-05938.AI4
O accesses), or DMA
2
4-1

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