RM0312 datasheet(256/275 Pages) STMICROELECTRONICS

256 / 275 page

ProxSense™ (PXS)

RM0312

256/275

DocID022352 Rev 3

22.7

Low power modes

22.7.1

Behavior in low power modes

22.7.2

Reducing power consumption

As for other peripherals, the consumption can be reduced when the peripheral is not used

by disabling the ProxSense and switching its clock in the CLK_PCKENiR register.

LOW_POWER bit

Setting the LOW_POWER bit in PXS_CR1 powers on the analog part of the ProxSense only

while a conversion is active. This introduces a stabilization time just after the START bit is

set, so in case of successive conversions with time constraints, it is recommended to clear

the LOW_POWER bit just before setting the START bit to avoid this stabilization between

the acquisitions.

Stabilization time

The ProxSense peripheral manages its stabilization automatically. In other words, if

software or the SYNC feature requests that a conversion is launched before it is stabilized,

the conversion is deferred and started automatically as soon as stabilization is complete.

The length of time required for the analog circuits to stabilize after powering on the

ProxSense is inversely related to the amount of current sunk by the ProxSense circuitry

during a conversion.

Examples include:

•

An extra 420 μs of stabilization time might be required if only a single channel is active,

with a charge-transfer frequency of 4 MHz, with BIAS = ‘10’, and with 10 pF on the Tx

line.

•

An extra 120 μs of stabilization time is required if several configured channels are

active.

The duration of the stabilization time can be reduced using the STAB[1:0] bits in register

PXS_CR3. This can reduce the overall current consumption of the application. By default, a

period of 1.7 ms is selected.

Table 55. Behavior in low power modes

Mode

Description

Wait

PXS interface is active.

Interrupt events cause the device to exit from Wait and Active-halt.

Active-halt

Halt

PXS interface is not active.

RM0312 датащи(PDF) 256 Page - STMicroelectronics

RM0312 датащи(HTML) 256 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 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL