HT45R37 datasheet(64/100 Pages) HOLTEK

64 / 100 page

HT45R37

Rev. 1.10

January 29, 2010

gether with fSYS/4, it is used as a clock source for certain

internal functions such as the Watchdog Timer, Buzzer,

RTC Interrupt and Time Base Interrupt. The internal

clock fS, is simply a choice of either fSUB or fSYS/4, using a

configuration option.

Operating Modes

After the correct clock source configuration selections

are made, overall operation of the chosen clock is

achieved using the CLKMOD register. A combination of

the HLCLK and IDLEN bits in the CLKMOD register and

use of the HALT instruction determine in which mode the

device will be run. The devices can operate in the follow-

ing Modes.

· Normal mode

fM on, fSLOW on, fSYS=fM, CPU on, fS on, fWDT on/off de-

pending upon the WDT configuration option and WDT

control register.

· Slow mode0

fM off, fSLOW=32K_INT oscillator or the 32768Hz oscil-

lator, fSYS=fSLOW, CPU on, fS on, fWDT on/off depending

upon the WDT configuration option and WDT control

· Slow mode1

fM on, fSLOW=fM/2~fM/64, fSYS=fSLOW, CPU on, fS on, fWDT

on/off depending upon the WDT configuration option

and WDT control register.

· Idle mode

fM,fSLOW,fSYS off, CPU off; fSUB on, fS on/off by selecting

fSUB or fSYS/4, fWDT on/off depending upon the WDT

configuration option and WDT control register.

· Sleep mode

fM,fSLOW,fSYS,fS, CPU off; fSUB,fWDT on/off depending

upon the WDT configuration option and WDT control

Switching Between Modes

The device switches between the different operating

modes using a combination of the HALT instruction and

the IDLEN bit in the CLKMOD register. Switching to one

of the lower power modes enables the normal operating

current to be reduced to a lower operating level or to a

very low standby current level, a feature which is very

important in low power battery applications.

C L K M O D R e g i s t e r

f S Y S s e l e c t

1 : f M

0 : f S L O W

I d l e m o d e

1 : e n a b l e

0 : d i s a b l e

H i g h o s c i l l a t o r r e a d y f l a g

1 : t i m e - o u t

0 : n o n - t i m e - o u t

L o w o s c i l l a t o r r e a d y f l a g

1 : t i m e - o u t

0 : n o n - t i m e - o u t

S P I / I C c o n t i n u e s r u n n i n g i n I d l e m o d e

1 : e n a b l e

0 : d i s a b l e

f S L O W s e l e c t i o n

b 0

I D L E N

H L C L K

H T O

L T O

b 7

S L O W C 0

S L O W C 1

S L O W C 2

f S L O W

f S L

f M / 6 4

f M / 3 2

f M / 1 6

f M / 8

f M / 4

f M / 2

S L O W W C 2

S L O W W C 1

S L O W W C 0

S I M I D L E

Clock Control Register

- CLKMOD

HT45R37 Datasheet(PDF) 64 Page - Holtek Semiconductor Inc

HT45R37 Datasheet(HTML) 64 Page - Holtek Semiconductor Inc

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

Datasheet Download

Link URL