SAB80C517-M16 SIEMENS [Siemens Semiconductor Group], SAB80C517-M16 Datasheet - Page 63

• Manufacturer Part Number: SAB80C517-M16
• Description: 8-Bit CMOS Single-Chip Microcontroller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

On-Chip Peripheral Components
Figure 7-14
Baud Rate Generator for Serial Interface 1
Figure 7-15
Special Function Register S1REL (Address 9D H )
9D H
Serial interface 1 reload register
S1REL
8-bit reload register for baud rate generator of serial interface 1.
7.2.2.4 New Baud Rate Generator for Serial Channel 1
A new baud rate generator for Serial Channel 1, which is implemented in SAB 80C517 devices with
stepping code "CA" or later, 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
/2 input frequency. On overflow of this timer there is an automatic
OSC
reload from the registers S1REL (address 9D H ) and S1RELH (address BB H ). The lower 8 bits of
the timer are reloaded from S0REL, while the upper two bits are reloaded from bit 0 and 1 of register
S1RELH. The baud rate timer is reloaded by writing to S1REL.
The baud rate in Mode A and B can be determined by the following formula:
oscillator frequency
Mode A, B baud rate =
10
32 x (2
– Reload Value)
with Reload Value = S1RELH.1 – 0, S1RELL.7 – 0
Semiconductor Group
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