AT89LP2052 datasheet(30/90 Pages) ATMEL

30 / 90 page

3547F–MICRO–6/06

AT89LP2052/LP4052

17.2

Baud Rates

The baud rate in Mode 0 is fixed as shown in the following equation.

The baud rate in Mode 2 depends on the value of the SMOD1 bit in Special Function Register

PCON.7. If SMOD1 = 0 (the value on reset), the baud rate is 1/32 of the oscillator frequency. If

SMOD1 = 1, the baud rate is 1/16 of the oscillator frequency, as shown in the following equation.

17.2.1

Using Timer 1 to Generate Baud Rates

The Timer 1 overflow rate determines the baud rates in Modes 1 and 3. When Timer 1 is the

baud rate generator, the baud rates are determined by the Timer 1 overflow rate and the value

of SMOD1 according to the following equation.

The Timer 1 interrupt should be disabled in this application. The Timer itself can be configured

for either timer or counter operation in any of its 3 running modes. In the most typical applica-

tions, it is configured for timer operation in auto-reload mode (high nibble of TMOD = 0010B). In

this case, the baud rate is given by the following formula.

Programmers can achieve very low baud rates with Timer 1 by configuring the Timer to run as a

16-bit auto-reload timer (high nibble of TMOD = 0001B). In this case, the baud rate is given by

the following formula.

Mode 0 Baud Rate

Oscillator Frequency

-------------------------------------------------------

Mode 2 Baud Rate

SMOD1

--------------------

(Oscillator Frequency)

SMOD1

--------------------

(Timer 1 Overflow Rate)

Modes 1, 3

Baud Rate

SMOD1

--------------------

Oscillator Frequency

256

TH1

()

–

[]

-------------------------------------------------------

Modes 1, 3

Baud Rate

SMOD1

--------------------

Oscillator Frequency

65536

RH1,RL1

()

–

[]

---------------------------------------------------------

Modes 1, 3

Baud Rate

AT89LP2052 датащи(PDF) 30 Page - ATMEL Corporation

AT89LP2052 датащи(HTML) 30 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

датащи скачать

ссылки URL