HT45F23 datasheet(66/152 Pages) HOLTEK

66 / 152 page

For the PFD output to function, it is essential that the corresponding bit of the Port A control register

PAC bit 5 is setup as an output. If setup as an input the PFD output will not function, however, the pin

can still be used as a normal input pin. The PFD output will only be activated if bit PA5 is set to

²1².

This output data bit is used as the on/off control bit for the PFD output. Note that the PFD output will

be low if the PA5 output data bit is cleared to

²0².

Using this method of frequency generation, and if a crystal oscillator is used for the system clock, very

precise values of frequency can be generated.

Prescaler

Bits T0PSC0~T0PSC2 of the TMR0C register can be used to define the pre-scaling stages of the

internal clock sources of the Timer/Event Counter 0. The Timer/Event Counter overflow signal can be

used to generate signals for the PFD and Timer Interrupt.

TMR0C Register

Bit

76543210

Name

T0M1

T0M0

T0ON

T0E

T0PSC2

T0PSC1

T0PSC0

R/W

POR

01000

Bit 7,6

T0M1, T0M0: Timer 0 operation mode selection

00: event counter mode, the input signal is from Comparator 1 output

01: event counter mode, the input signal is from TC0 pin.

10: timer mode

11: pulse width capture mode

Bit 5

unimplemented, read as

²0²

Bit 4

T0ON: Timer/Event Counter counting enable

0: disable

1: enable

Bit 3

T0E:

Event counter active edge selection

0: count on raising edge

1: count on falling edge

Pulse Width Capture active edge selection

0: start counting on falling edge, stop on rasing edge

1: start counting on raising edge, stop on falling edge

Bit 2~0

T0PSC2, T0PSC1, T0PSC0: Timer prescaler rate selection

Timer internal clock=

000: fSYS

001: fSYS/2

010: fSYS/4

011: fSYS/8

100: fSYS/16

101: fSYS/32

110: fSYS/64

111: fSYS/128

Rev. 1.20

September 15, 2011

HT45F23/HT45F43

8-Bit Flash MCU with Op Amps & Comparators

T i m e r O v e r f l o w

P F D C l o c k

P A 5 D a t a

P F D O u t p u t a t P A 5

PFD Output Control

HT45F23 Datasheet(PDF) 66 Page - Holtek Semiconductor Inc

HT45F23 Datasheet(HTML) 66 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 ...More

Datasheet Download

Link URL