PIC18F44J10-ESLASHP datasheet(42/358 Pages) MICROCHIP

42 / 358 page

PIC18F45J10 FAMILY

DS39682C-page 40

Preliminary

4.5

Power-up Timer (PWRT)

PIC18F45J10 family devices incorporate an on-chip

Power-up Timer (PWRT) to help regulate the Power-on

Reset process. The PWRT is always enabled. The

main function is to ensure that the device voltage is

stable before code is executed.

The Power-up Timer (PWRT) of the PIC18F45J10

family devices is an 11-bit counter which uses the

INTRC source as the clock input. This yields an

approximate time interval of 2048 x 32

μs= 65.6 ms.

While the PWRT is counting, the device is held in

Reset.

The power-up time delay depends on the INTRC clock

and will vary from chip to chip due to temperature and

process variation. See DC parameter 33 for details.

4.5.1

TIME-OUT SEQUENCE

If enabled, the PWRT time-out is invoked after the POR

pulse has cleared. The total time-out will vary based on

the status of the PWRT. Figure 4-3, Figure 4-4,

Figure 4-5

and

Figure 4-6

all

depict

time-out

sequences on power-up with the Power-up Timer

enabled.

Since the time-outs occur from the POR pulse, if MCLR

is kept low long enough, the PWRT will expire. Bringing

MCLR

high

will

begin

execution

immediately

(Figure 4-5). This is useful for testing purposes, or to

synchronize more than one PIC18F device operating in

parallel.

FIGURE 4-3:

TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD, VDD RISE < TPWRT)

FIGURE 4-4:

TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1

TPWRT

VDD

MCLR

INTERNAL POR

PWRT TIME-OUT

INTERNAL RESET

TPWRT

VDD

MCLR

INTERNAL POR

PWRT TIME-OUT

INTERNAL RESET

PIC18F44J10-E/P Datasheet(PDF) 42 Page - Microchip Technology

PIC18F44J10-E/P Datasheet(HTML) 42 Page - Microchip Technology

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