SRI2K datasheet(16/45 Pages) STMICROELECTRONICS

16 / 45 page

Memory mapping

SRI2K

16/45

Doc ID 15779 Rev 3

4.2

32-bit binary counters

The two 32-bit binary counters located at block addresses 5 and 6, respectively, are used to

count down from 232 (4096 million) to 0. The SRI2K uses dedicated logic that only allows

the update of a counter if the new value is lower than the previous one. This feature allows

the application to count down by steps of 1 or more. The initial value in Counter 5 is

FFFF FFFEh and is FFFF FFFFh in Counter 6. When the value displayed is 0000 0000h,

the counter is empty and cannot be reloaded. The counter is updated by issuing the

Write_block command to block address 5 or 6, depending on which counter is to be

updated. The Write_block command writes the new 32-bit value to the counter block

address. Figure 16 shows examples of how the counters operate.

The counter programming cycles are protected by automated antitearing logic. This function

allows the counter value to be protected in case of power down within the programming

cycle. In case of power down, the counter value is not updated and the previous value

continues to be stored.

Figure 15.

Binary counter (addresses 5 to 6)

Figure 16.

Countdown example (binary format)

The counter with block address 6 controls the Reload command used to reset the resettable

OTP area (addresses 0 to 4). Bits b31 to b21 act as an 11-bit Reload counter; whenever one

of these 11 bits is updated, the SRI2K detects the change and adds an Erase cycle to the

Write_block command for locations 0 to 4 (see the “Resettable OTP area” paragraph). The

Erase cycle remains active until a Power-off or a Select command is issued. The SRI2K’s

resettable OTP area can be reloaded up to 2 047 times (211-1).

Block

Address

MSb

b31

32-bit block

b16 b15

b24 b23

b8 b7

LSb

Description

Count down

Counter

32-bit binary counter

ai07660b

ai07661

...1111111111111

...111111111111

...

11111111111

Initial data

1-unit decrement

b31

...

11111111111

...

111111111

0100

...111111111

1000

1-unit decrement

8-unit decrement

Increment not allowed

SRI2K 数据表(PDF) 16 Page - STMicroelectronics

SRI2K 数据表(HTML) 16 Page - STMicroelectronics

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

数据表下载