EECS 150 Spring 2007

Checkpoint 0 - SDRAM

2/23/2007

Jeff Kalvass(Adapted From Greg Gibeling)

Welcome to Checkpoint 0 Agenda

Why Checkpoint 0 is Important Checkpoint 0 Specs Theory of SDRAM SDRAM Init, Read, Write (timing

diagrams) Designing the SDRAM controller

Motivation Learn to configure

external SDRAM Write and read from

external SDRAM To use FIFOs as buffers Design a memory

controller You will need this for the

project

SDRAM(Checkpoint #0)

MultiportArbitration

What is Checkpoint 0? (1) Initialize and configure SDRAM We provide 32-bit data generator The black box we provide will

handle all read and write requests We will provide addressing scheme

What is Checkpoint 0 (2) We provide data checker to

compare what is read from SDRAM from what should have been written

Count the errors and display on LEDs

What is Checkpoint 0? (3)

Theory of SDRAM (1) SDRAM: Synchronous Dynamic

RAM Upside

Huge amounts of storage Down side

Slow May need refreshing every once in a

while

Theory of SDRAM (2) So to speed things up…

SDRAM handles bursts to read data as a group

Control requires precise timing Issue sequences of commands Timing must be matched with Data Sheet

(more on this later)

Theory of SDRAM (3) DRAM is BIG so we time mux

address Row Address Column Address

Steps to Read/Write Send Row Address Send Column Address Send/Get Data

Read the Data sheet for details

Theory of SDRAM (4) SDRAM is a large FSM

Send it a command Get a response

SDRAM Controller’s Job: Send the right command signals Ensure command sequences are

timed correctly

SDRAM Specifications See Spec at

http://www-inst.eecs.berkeley.edu/~cs150/sp07/Documents.php#Datasheets

Read the MT48LC16M16 Datasheet Provides overview of commands and

timing You will need to become very familiar

with initialization, reads, and writes

SDRAM Initialization (p 40)

Read Operation (p 46)

Write Operation (p 53)

Write Timing

• Memory chips are the -7E Models, and the clock is running at 27MHz

SDRAM Controller (1) One Time

Initialization Repeating

Read with auto-precharge Write with auto-precharge Auto-Refresh (only if idle for a long

time)

SDRAM Controller (2) Goal

Abstracts away the details of SDRAM Accepts commands, produces responses Deals with sending address in parts (row

and then column) Design Options

One large FSM, one small FSM with a counter, man small interacting FSMs, etc.

SDRAM Controller (3) Design for the future! You will

need it for your project Tristate data line when reading!

FIFOs

Buffer to match two data rates

Great for data path clock domain crossings (we’ll talk about it later this semester)

The Checkpoint (1) You have one week to complete this

CP Design Reviews next week at the

beginning of your lab section (remember Lab 5 checkoff) Bubble-and-arc diagram(s) required Block Diagram highly recommended Timing diagram required

Example: read and write

The Checkpoint (2) Construction

Demo circuit on board for check-off Remember you will be designing for CP1

concurrently Groups of two – your lab #4/#5

partner You must get checked off in the same

lab section for the rest of the semester Start designing today!

Any Questions? Your friendly neighborhood lab TA

is here We want high completion for CP0,

get help if you need it! Sign-up sheet for partner/grading