Intel 8xC251TB - Manual (Page 16)

8xC251Tx Hardware Description
10
3.2.2 SBUF1
Address: 9BH
Reset Value: xxxx xxxxB
To send serial data, software writes a byte to SBUF1 and to receive serial data, software reads from SBUF1.
3.2.3 SADDR1
Address: AAH
Reset Value: 0000 0000B
Slave Individual Address Register1 (SADDR1) contains the device’s individual address for multiprocessor
communications.
3.2.4 SADEN1
Address: BAH
Reset Value: 0000 0000B
Mask Byte Register 1 (SADEN1) masks bits in the SADDR1 register to form the devices given address for
multiprocessor communications.
3.2.5 BGCON
Address: 8FH
Reset Value: 0000 xxxxB
Table 7. BGCON Special Function Register Definitions
Bit Number
Bit Mne-
monic
Function
7 SMOD1 Double Baud Rate Bit:
When set, doubles the baud rate for the second serial I/O port when timer 1
is used and mode 1, 2 or 3 is selected in the SCON1 register.
6 SMOD0 SCON1.7 Select:
When set, read/write accesses to SCON1.7 are to the FE1 bit. When
cleared, read/write accesses to SCON1.7 are to the SM0 bit.
5 RCLK1 Second Serial I/O Port Receive Clock Bit:
Selects timer 2 overflow pulses (RCLK1 = 1) or timer 1 overflow pulses
(RCLK1 = 0) as the baud rate generator for the serial port modes 1 and 3.
4 TCLK1 Second Serial I/O Port Transmit Clock Bit:
Selects timer 2 overflow pulses (TCLK = 1) or timer 1 overflow pulses
(TCLK1 = 0) as the baud rate generator for the serial port modes 1 and 3.
3 - 0 - Reserved.