SE97BTP datasheet(20/53 Pages) NXP

20 / 53 page

SE97B_1

Product data sheet

Rev. 01 — 27 January 2010

20 of 53

NXP Semiconductors

SE97B

DDR memory module temp sensor with integrated SPD

7.10.3 Read operations

7.10.3.1

Current address read

In Standby mode, the SE97B internal address counter points to the data byte immediately

following the last byte accessed by a previous operation. If the ‘previous’ byte was the last

byte in memory, then the address counter will point to the first memory byte, and so on. If

the SE97B decodes a slave address with a ‘1’ in the R/W bit position (Figure 15), it will

issue an Acknowledge in the ninth clock cycle and will then transmit the data byte being

pointed at by the address counter. The master can then stop further transmission by

issuing a No Acknowledge on the ninth bit then followed by a STOP condition.

7.10.3.2

Selective read

The read operation can also be started at an address different from the one stored in the

address counter. The address counter can be ‘initialized’ by performing a ‘dummy’ write

operation (Figure 16). The START condition is followed by the slave address (with the

R/W bit set to ‘0’) and the desired byte address. Instead of following-up with data, the

master then issues a second START, followed by the ‘Current Address Read’ sequence,

as described in Section 7.10.3.1.

Fig 15. Current address read timing

A2 A1 A0

slave address (memory)

START condition

R/W acknowledge

from slave

data from memory

SDA

002aab251

STOP condition

no acknowledge

from master

Fig 16. Selective read timing

A2 A1 A0

slave address (memory)

START condition

R/W acknowledge

from slave

acknowledge

from slave

word address

SDA

002aac901

STOP condition

data from memory

no acknowledge

from master

A2 A1 A0

slave address (memory)

START condition

R/W acknowledge

from slave

SE97BTP Datasheet(PDF) 20 Page - NXP Semiconductors

SE97BTP Datasheet(HTML) 20 Page - NXP Semiconductors

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53

Datasheet Download

Link URL