Datasheet

STPM10 Theory of operation
Doc ID 17728 Rev 4 33/53
7.18 Mode signals
The STPM10 includes 8 mode signals located in the DFP data record. 3 of these are used
only for internal testing purposes while 5 are useful to change some of the operations of the
STPM10. The mode signals are not retained when the STPM10 supply is not available and
they are cleared when a POR occurs, but they are not cleared when a remote reset
command (RRR) is sent through SPI.
The mode signals bit can be written using the normal writing procedure of the SPI interface
(see Section 7.19).
– CSEL: In normal operation, if the anti-tamper module is not activated (see PST
configuration bits) the STPM10 selects channel 1 as the source of current
information. For debug or calibration purposes it is possible to select channel 2 as the
source of the current channel signal when the tamper module is disabled. This is
done by setting the CSEL mode bit.
– Precharge: This command swaps the sequence of data records read, allowing the
reading of the last four data records first, and the first four second. The reading
sequence is 5, 6, 7, 8, 1, 2, 3, 4. Unlike the other mode signals, the precharge
command is not retained inside the STPM10, but should be sent each time before the
reading of the data records.
– BANK: it is used to activate RC oscillator (see Section 7.11.1).
–
–
–
–
–
Table 12. Mode signal description
Bit #
Signal
name
Bit
value
Status
Binary
command
Hex
command
0 BANK
0
Used for RC startup procedure
0111000x 70 or 71
1 1111000x F0 or F1
1 Reserved
2 Reserved
3 Reserved
4 CSEL
0 Current channel 1 selected when tamper is disabled 0111 100x 78 or 79
1 Current channel 2 selected when tamper is disabled 1111 100x F8 or F9
5 Reserved
6 Reserved
7 Precharge 1
Swap the 32-bit data record readings. From
1,2,3,4,5,6,7,8, to 5,6,7,8,1,2,3,4 and vice-versa
1111111x FF