P87LPC767 View Datasheet(PDF) - Philips Electronics

Part Name

Description

Manufacturer

P87LPC767

Low power, low price, low pin count (20 pin) microcontroller with 4-kbyte OTP and 8-bit A/D converter

Philips Electronics 

Philips Semiconductors

Low power, low price, low pin count (20 pin)

microcontroller with 4-kbyte OTP and 8-bit A/D converter

Product data

87LPC767

Baud Rates

The baud rate in Mode 0 is fixed: Mode 0 Baud Rate = CPU clock/6.

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

Special Function Register PCON. If SMOD1 = 0 (which is the value

on reset), the baud rate is 1/32 of the CPU clock frequency. If

SMOD1 = 1, the baud rate is 1/16 of the CPU clock frequency.

Mode

2

Baud

Rate

+

1

)

SMOD1

32

CPU clock frequency

Using Timer 1 to Generate Baud Rates

When Timer 1 is used as the baud rate generator, the baud rates in

Modes 1 and 3 are determined by the Timer 1 overflow rate and the

value of SMOD1. The Timer 1 interrupt should be disabled in this

application. The Timer itself can be configured for either “timer” or

“counter” operation, and in any of its 3 running modes. In the most

typical applications, it is configured for “timer” operation, in the

auto-reload mode (high nibble of TMOD = 0010b). In that case the

baud rate is given by the formula:

CPU clock frequencyń

192 (or 96 if SMOD1 + 1)

Mode 1, 3 Baud Rate +

256 * (TH1)

Tables 6 and 7 list various commonly used baud rates and how they

can be obtained using Timer 1 as the baud rate generator.

Table 9. Baud Rates, Timer Values, and CPU Clock Frequencies for SMOD1 = 0

Timer Count

2400

4800

Baud Rate

9600

19.2k

38.4k

–1

0.4608

0.9216

* 1.8432

* 3.6864

* 7.3728

–2

0.9216

1.8432

* 3.6864

* 7.3728

* 14.7456

–3

1.3824

2.7648

5.5296

* 11.0592

–

–4

* 1.8432

* 3.6864

* 7.3728

* 14.7456

–

–5

2.3040

4.6080

9.2160

* 18.4320

–

–6

2.7648

5.5296

* 11.0592

–

–

–7

3.2256

6.4512

12.9024

–

–

–8

* 3.6864

* 7.3728

* 14.7456

–

–

–9

4.1472

8.2944

16.5888

–

–

–10

4.6080

9.2160

* 18.4320

–

–

57.6k

* 11.0592

–

–

–

–

–

–

–

–

2001 Aug 07

36

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