DS80C320-MCG Datasheet, PDF (141/175 Pages) Dallas Semiconductor – High-Speed Microcontroller User Guide

High-Speed Microcontroller User’s Guide
SM0/FE_0 SM1_0 Mode Function Length Period
0
0
0
Sync
8 bits 4/12 t_CL
(see SM2)
0
1
1
Asynch 10 bits Timer 1 or 2
1
0
2
Asynch 11 bits 64/32 t_CLK
1
1
3
Asynch 11 bits Timer 1 or 2
Initialization:
SCON is set to 00h on a reset.
Read/Write Access:
Unrestricted.
SERIAL PORT
SCON1; C0h
CONTROL ONE
Serial Port 1 performs identically to the standard Serial Port 0 on an 80C32 with one exception. The baud
rate generation from Timer 2 is not available in Modes 1 and 3. Timer 1 is used. The port is located at
P1.3 and P1.2 for TXD1 and RXD1 respectively.
SCON1.7
SM0/FE_1 - Serial Port 1 Mode bit 0 or Framing Error Flag.
PCON.6 (SMOD0) determines whether this bit functions as SM0 or
FE. The operation of SM0 (SMOD0 = 0) is described in the table
below. When SMOD0 = 1, the serial port will set FE to indicate an
invalid stop bit. When used as FE, this bit must be cleared in
software.
SCON1.6
SM1_1 - Serial Port 1 mode select 1. The operation of SM1_1 is
described in the table below.
SCON1.5
SCON1.4
SM2_1 - Multiple MCU communication. Setting this bit to a one
enables multiprocessor communication in Modes 2 or 3. If the ninth
bit is 0, the RI_1 will not be set. In Mode 1, setting the SM2_1 bit
to a one causes the RI_1 bit not to be set if a valid stop bit is not
received. In the High-Speed Microcontroller, SM2_1 also has a
new function. In mode 0, the SM2_1 bit controls whether the serial
port clock runs at a divide by 4 or a divide by 12 of the oscillator
when not in PMM. When set to a logic 0, the serial port runs at a
divide by 12. When set to a logic one, the serial port runs at a divide
by 4. This results in much faster synchronous serial communication.
REN_1 - Receive Enable. When set to a 1, the receive shift register
will be enabled.
SCON1.3
TB8_1 - Set/clear to define the state of the ninth transmission data
bit in modes 2 and 3.
SCON1.2
RB8_1 - Indicates the state of an incoming ninth bit when in modes
2 and 3. In mode 1, when SM2 = 0, RB8 is the state of the stop bit
received. RB8 is not used in mode 0.
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