Siemens SAB 80515 Series User Manual page 49

The control and status bits of the serial channel in special function register SCON are illustrated in
figure 7-8. Figure 7-7 shows the special function register SBUF which is the data register for
receive and transmit. The following table summarizes the operating modes of the serial interface.
Table 7-3
Serial Interface, Mode Selection
SM0 SM1
0 0
0 1
1 0
1 1
Figure 7-8
Special Function Register SBUF (Address 99 H )
99 H
Receive and transmit buffer of serial interface. Writing to SBUF loads the transmit register and
initiates transmission. Reading out SBUF accesses a physically separate receive register.
Semiconductor Group
Mode
0
1
2
3
Serial interface buffer register
*
49
On-Chip Peripheral Components
Descriptions
Shift register
8-bit UART
9-bit UART
9-bit UART
Baud Rate
f
/12
OSC
Variable
f f
/64 or /32
OSC OSC
Variable
SBUF