RM0312 datasheet(260/275 Pages) STMICROELECTRONICS

260 / 275 page

ProxSense™ (PXS)

RM0312

260/275

DocID022352 Rev 3

22.9.3

ProxSense Control Register 3 (PXS_CR3)

Address offset: 0x02

Reset value: 0x04

Bit 1SYNCEN: Enable synchronization (SYNC) feature

0: Disable the SYNC feature

1: Enable the SYNC feature

This feature cannot be used with Active-halt mode: transitions on the PXS_TRIG input are not

recognized during Active-halt mode.

Bit 0SYNCEDGE: Synchronization edge selection

0: Launch conversion on the falling edge of the PXS_TRIG input (when SYNCEN = 1)

1: Launch conversion on the rising edge of the PXS_TRIG input (when SYNCEN = 1)

76543210

STAB[1:0]

BIAS[1:0]

VTHR[3:0]

Bits 7:6 STAB[1:0]: Selection for stabilization time after ProxSense power-on

00: 1.7 ms, can be used for all configurations.

01: 500 µs, can be used when at least one channel with moderate consumption (>170 µA) is

activated.

10: 120 µs, can be used when several channels are activated in Projected mode

11: Reserved, do not use this selection

This stabilization time is applied at the beginning of the first conversion after each time the ProxSense

is powered on (on every conversion when LOW_POWER = 1).

Bits 5:4 BIAS[1:0]: Sample and hold strength selection

00: 2.5 µA

01: 5 µA

10: 7.5 µA

11: 10 µA

This is the nominal bias current for the OpAmps which maintain the PXS_RXn pins at the final

(discharged) voltage while the transmit lines are transitioning (back) low. This function is valid only for

projected capacitance measurements. A higher bias is needed when the projected capacitance (the

capacitance between each Rx line and each Tx line) is high.

Note: This register can be modified only when PXSEN = 0.

Bits 3:0 VTHR[3:0]: Threshold voltage (VTHR) selection

0000: 0.5 x VREG

...

0100: 0.61 x VREG (default after reset)

...

1111: 0.9 x VREG

The threshold voltage can be set to values between 0.5 * VREG and 0.9 * VREG using VTHR[3:0]:

VREG = 0.02667 x VTHR x VREG + VREG/2

When the voltage on a given sampling capacitor (CS) reaches VTHR, the conversion for the

corresponding receive channel is completed.

Note: This register can be modified only when PXSEN = 0.

RM0312 датащи(PDF) 260 Page - STMicroelectronics

RM0312 датащи(HTML) 260 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