Siemens EF 88H Series Manual de usuario descargar pdf (Pagina 52)

Semiconductor Group 5 - 17

On-Chip Peripheral Components

5.4.2 Serial Channel 1 Baud Rate Generator

A new baud rate generator for Serial Channel 1 now offers a wider range of selectable baud rates.

Especially a baud rate of 1200 baud can be achieved now.

The baud rate generator itself is identical with the one used for Serial Channel 0. It consists of a free

running 10-bit timer with F

OSC

/2 input frequency. On overflow of this timer there is an automatic

reload from the registers S1RELL (address 9D

) and S1RELH (address BB

). The lower 8 bits of

the timer are reloaded from S1RELL, while the upper two bits are reloaded from bit 0 and 1 of

The baud rate in mode A and B can be determined by the following formula:

with S1REL = S1RELH.1 – 0, S1RELL.7 – 0

Figure 5-6 shows a block diagram of the baud rate generator for Serial Interface 1.

Figure 5-6

Baud Rate Generator for Serial Interface 1

Mode A, B baud rate =

oscillator frequency

32 x (2

– S1REL)

1 2 ... 47 48 49 50 51 52 53 54 55 56 57 ... 136 137

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Siemens EF 88H Series Manual de usuario Pagina 52