AT89C5132-ROTUL datasheet(50/181 Pages) ATMEL

50 / 181 page

4173D–USB–02/06

AT89C5132

Figure 12-1. Timer 0 and Timer 1 Clock Controller and Symbols

12.3

Timer 0

Timer 0 functions as either a Timer or event Counter in four modes of operation. Figure 12-2

through Figure 12-8 show the logical configuration of each mode.

Timer 0 is controlled by the four lower Bits of TMOD register (see Table 41) and Bits 0, 1, 4 and

5 of TCON register (see Table 40). TMOD register selects the method of Timer gating (GATE0),

Timer or Counter operation (C/T0#) and mode of operation (M10 and M00). TCON register pro-

vides Timer 0 control functions: overflow flag (TF0), run control bit (TR0), interrupt flag (IE0) and

interrupt type control bit (IT0).

For normal Timer operation (GATE0 = 0), setting TR0 allows TL0 to be incremented by the

selected input. Setting GATE0 and TR0 allows external pin INT0 to control Timer operation.

Timer 0 overflow (count rolls over from all 1s to all 0s) sets TF0 flag generating an interrupt

request.

It is important to stop Timer/Counter before changing mode.

12.3.1

Mode 0 (13-bit Timer)

Mode 0 configures Timer 0 as a 13-bit Timer which is set up as an 8-bit Timer (TH0 register) with

a modulo 32 prescaler implemented with the lower five Bits of TL0 register (see Figure 12-2).

The upper three Bits of TL0 register are indeterminate and should be ignored. Prescaler over-

flow increments TH0 register. Figure 12-3 gives the overflow period calculation formula.

Figure 12-2. Timer/Counter x (x = 0 or 1) in Mode 0

Figure 12-3. Mode 0 Overflow Period Formula

PER

CLOCK

TIM0

CLOCK

OSC

CLOCK

T0X2

CKCON.1

÷ 2

Timer 0 Clock

Timer 0 Clock Symbol

PER

CLOCK

TIM1

CLOCK

OSC

CLOCK

T1X2

CKCON.2

÷ 2

Timer 1 Clock

Timer 1 Clock Symbol

TIMx

CLOCK

TRx

TCON Reg

TFx

TCON Reg

GATEx

TMOD Reg

÷ 6

Overflow

Timer x

Interrupt

Request

C/Tx#

TMOD Reg

THx

(8 Bits)

TLx

(5 Bits)

INTx

⋅ (16384 – (THx, TLx))

TFx

PER=

TIMx

AT89C5132-ROTUL Folha de dados(PDF) 50 Page - ATMEL Corporation

AT89C5132-ROTUL Folha de dados(HTML) 50 Page - ATMEL Corporation

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

Folha de dados Download

Ligação URL