Siemens EF 88H Series Manual de usuario descargar pdf (Pagina 67)

Semiconductor Group 6-33

On-Chip Peripheral Components

C501

6.3.3.1 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 SMOD as follows:

Modes 1,3 baud rate = 2

SMOD

/32×(timer 1 overflow rate)

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

Modes 1,3 baud rate = 2

SMOD

/32×f

OSC

/ [12×(256–TH1)]

One can achieve very low baud rates with timer 1 by leaving the timer 1 interrupt enabled, and

configuring the timer to run as a 16-bit timer (high nibble of TMOD = 0001

), and using the timer 1

interrupt to do a 16-bit software reload.

Table 6-7 lists commonly used baud rates and how they can be obtained from timer 1.

Table 6-7

Timer 1 Generated Commonly Used Baud Rates

Baud Rate

OSC

SMOD Timer 1

C/T Mode Reload

Value

Mode 0 max: 1 MHz

Mode 2 max: 375 K

Modes 1, 3: 62.5 K

19.2 K

9.6 K

4.8 K

2.4 K

1.2 K

110

12 MHz

11.059 MHz

6MHz

12 MHz

FEEB

1 2 ... 62 63 64 65 66 67 68 69 70 71 72 ... 120 121

Comentarios a estos manuales

Sin comentarios

Siemens EF 88H Series Manual de usuario Pagina 67

Comentarios a estos manuales

Relacionado con productos y manuales para Placas Siemens EF 88H Series