STPM01 datasheet(39/56 Pages) STMICROELECTRONICS

39 / 56 page

STPM01

Theory of operation

39/56

t1 →t2: Latching Phase. Interval value>2/fCLK

t2 →t3: Data latched, SPI idle. Interval value > 30ns

t3 →t4: Enable SPI for read operation. Interval value > 30ns

t4 →t5: Serial clock counter is reset. Interval value > 30ns

t5 →t6: SPI reset and enabled for read operation. Interval value > 30ns

t7: Internal data transferred to SDATD

t8: SDATD data is stable and can be read

The system that reads the data record from the STPM01 should check the integrity of each

data record. If the check fails, the reading should be repeated, but this time only the shifting

should be applied otherwise a new data would be latched into transmission latches and

incorrectly read one would be lost.

Normally, each byte is read out as most significant bit (msb) first. But this can be changed by

setting the MSBF configuration bit in the STPM01 CFL data record. If this is done, each byte

is read out as least significant bit (lsb) first.

8.23

Writing procedure

Each writable bit (Configuration and Mode bits) has its own 6-bit absolute address. For the

configuration bits, the 6-bit address value corresponds to its decimal value, while for the

mode bits the addresses are the ones indicated in the Mode Signal paragraph.

In order to change the state of some latch one must send to STPM01 a byte of data which is

normal way to send data via SPI. This byte consists of 1-bit data to be latched (msb),

followed by 6-bit address of destination latch, followed by 1-bit don’t care data (lsb) which

makes total 8 bits of command byte.

For example, if we would like to set the configuration bit 47 (part of the secondary current

channel calibrator) to 0, we must convert the decimal 47 to its 6-bit binary value: 101111.

The byte command will be then composed like this:

Figure 25.

Timing for data records reading

4 t5

7 t8

1stbyte

stbitof3

yte

f(re

1stbyte

stbitof3

yte

f(re

STPM01 数据表(PDF) 39 Page - STMicroelectronics

STPM01 数据表(HTML) 39 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 46 47 48 49 50 51 52 53 54 55 56

数据表下载