FS91M68

R2F Conversion Module

Address

Name

Content

bit7

bit6

bit5

bit4

bit3

bit2

bit1

bit0

00EH

PT1MR

BPE2

BPE1

CH_S

RF_EN

-

-

-

-

018H

CKCON

LCD_S

PMPEN

PCK_S

BP_S

TMRST

GT_S[2：0]

019H

TMCNTH

TMCNT[15：8]

01AH

TMCNTL

TMCNT[7：0]

01BH

RSCNTH

RSCNT[15：8]

01CH

RSCNTL

RSCNT[7：0]

01DH

LowBatDct

lbEN

lowPwr

-

-

-

-

BiasSEL1 BiasSEL0

RF_EN enables R/F (Resistor to Frequency) switch module.

CH_S=0 selects reference resistor (RF part) oscillator, CH_S=1 selects sensor resistor (RS part) oscillator.

LCD_S：LCD clock setup.

PMPEN：Clock enable in step-up circuit.

PCK_S：Clock setup in step-up circuit.

BP_S：Buzzer clock setup.

TMCNT is the Timer for Gate time; RSCNT is The Counter for RF module.

GT_S is for Gate time setting of RF module, please refer to the table below.

TMRST：”0” clears all counter and stops counting;” 0 1 ” starts to count until Gate time interrupt occurs.

When TMCNT re-counts, TMRST must be set as 0 first, so TMCNT and RSCNT will be cleared

as 0. When TMRST is set as 1, TMCNT and RSCNT start counting until TMCNT[N]1

0. Then

TMCNT and RSCNT stop counting and store the value at the same time.

Rs

2200pF

Vref

Inside FS91M68

Rf

Rs

Rf

SC

Analog Switch

TMCNT [7:0]

Fsys

TMCNT [15:8]

GT_S [2:0]

Interrupt Signal

TMRST

RSCNT [15:0]

CPU

EN

Figure 10-4 R2F Conversion Module

Rev. 1.3

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