DS80C320-MCG Datasheet, PDF (39/175 Pages) Dallas Semiconductor – High-Speed Microcontroller User Guide

Serial Port Control (SCON1)
7
6
5
SFR C0h SM0/FE_1 SM1_1 SM2_1
RW-0 RW-0 RW-0
4
REN_1
RW-0
High-Speed Microcontroller User’s Guide
3
TB8_1
RW-0
2
RB8_1
RW-0
1
TI_1
RW-0
0
RI_1
RW-0
R=Unrestricted Read, W=Unrestricted Write, -n=Value after Reset
SM0-2
Bits 7-5
Serial Port 1 Mode. These bits control the mode of serial port 1 as shown
below. In addition, the SM0 and SM2 bits have secondary functions as Shown
below.
SM0
0
0
0
1
1
1
1
SM1
0
0
1
0
0
1
1
SM2
0
1
X
0
1
0
1
MODE
FUNCTION
LENGTH
PERIOD
0 Synchronous
8 bits
12t_CLK
0 Synchronous
8 bits
4t_CLK
1 Asynchronous
10 bits
Timer 1 baud rate
equation
2 Asynchronous
11 bits
2 Asynchronous w/ Multiprocessor 11 bits
communication
64t_CLK (SMOD=0)
32t_CLK (SMOD=1)
64t_CLK (SMOD=0)
32t_CLK (SMOD=1)
3 Asynchronous
11 bits
Timer 1 baud rate
equation
3 Asynchronous w/ Multiprocessor 11 bits
communication
Timer 1 baud rate
equation
SM0/FE_1
Bit 7
SM1_1
Bit 6
SM2-2
Bit 5
Framing Error Flag. When SMOD0 (PCON.6)=0, this bit (SM0) is used to
select the mode for serial port 1. When SMOD0 (PCON.6)=1, this bit (FE) will
be set upon detection of an invalid stop bit. When used as FE, this bit must be
cleared in software. Once the SMOD0 bit is set, modifications to this bit will
not affect the serial port mode settings. Although accessed from the same
register, internally the data for bits SM0 and FE are stored in different locations.
No alternate function.
Multiple CPU Communications. The function of this bit is dependent on the
serial port 1 mode.
Mode 0: Selects 12 t_CLK or 4t_CLK period for synchronous port 1 data transfers.
Mode 1: When this bit is set, reception is ignored (RI_1) is not set) if invalid
stop bit received.
Mode 2/3: when this bit is set, multiprocessor communications are enabled in
mode 2 and 3. This will prevent RI_1 from being set, and an interrupt being
asserted, if the 9^th bit received is not 1.
39 of 175