M58WR032EB datasheet(27/81 Pages) STMICROELECTRONICS

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M58WR032ET, M58WR032EB

(no wrap). The Wrap Burst bit is used to select be-

tween wrap and no wrap. When the Wrap Burst bit

is set to ‘0’ the burst read wraps; when it is set to

‘1’ the burst read does not wrap.

Burst length Bits (CR2-CR0)

The Burst Length bits set the number of Words to

be output during a Synchronous Burst Read oper-

ation as result of a single address latch cycle.

They can be set for 4 words, 8 words or continu-

ous burst, where all the words are read sequential-

ly.

In continuous burst mode the burst sequence can

cross bank boundaries.

In continuous burst mode or in 4, 8 words no-wrap,

depending on the starting address, the device as-

serts the WAIT output to indicate that a delay is

necessary before the data is output.

If the starting address is aligned to a 4 word

boundary no wait states are needed and the WAIT

output is not asserted.

If the starting address is shifted by 1,2 or 3 posi-

tions from the four word boundary, WAIT will be

asserted for 1, 2 or 3 clock cycles when the burst

sequence crosses the first 64 word boundary, to

indicate that the device needs an internal delay to

read the successive words in the array. WAIT will

be asserted only once during a continuous burst

access. See also Table 10., Burst Type Definition.

CR14, CR5 and CR4 are reserved for future use.

Table 9. Configuration Register

Bit

Description

Value

Description

CR15

Read Select

Synchronous Read

Asynchronous Read (Default at power-on)

CR14

Reserved

CR13-CR11

X-Latency

010

2 clock latency

011

3 clock latency

100

4 clock latency

101

5 clock latency

111

Reserved (default)

Other configurations reserved

CR10

Wait Polarity

WAIT is active Low

WAIT is active high (default)

CR9

Data Output

Configuration

Data held for one clock cycle

Data held for two clock cycles (default)

CR8

Wait Configuration

WAIT is active during wait state

WAIT is active one data cycle before wait state (default)

CR7

Burst Type

Interleaved

Sequential (default)

CR6

Valid Clock Edge

Falling Clock edge

Rising Clock edge (default)

CR5-CR4

Reserved

CR3

Wrap Burst

0Wrap

No Wrap (default)

CR2-CR0

Burst Length

001

4 words

010

8 words

111

Continuous (CR7 must be set to ‘1’) (default)

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