Datasheet

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SBAS323G − JUNE 2004 − REVISED OCTOBER 2007
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Serial Port 0 Control (SCON0)
7 6 5 4 3 2 1 0 Reset Value
SFR 98h SM0_0 SM1_0 SM2_0 REN_0 TB8_0 RB8_0 TI_0 RI_0 00h
SM0−2 Serial Port 0 Mode. These bits control the mode of serial Port 0. Modes 1, 2, and 3 have 1 start and 1 stop bit in
bits 7−5 addition to the 8 or 9 data bits.
MODE SM0 SM1 SM2 FUNCTION LENGTH PERIOD
0 0 0 0 Synchronous 8 bits 12 p
CLK
(1)
0 0 0 1 Synchronous 8 bits 4 p
CLK
(1)
1
(2)
0 1 0 Asynchronous 10 bits Timer 1 or 2 Baud Rate Equation
1
(2)
0 1 1 Valid Stop Required
(3)
10 bits Timer 1 Baud Rate Equation
2 1 0 0 Asynchronous 11 bits 64 p
CLK
(1)
(SMOD = 0)
32 p
CLK
(1)
(SMOD = 1)
2 1 0 1 Asynchronous with Multiprocessor Communication
(4)
11 bits 64 p
CLK
(1)
(SMOD = 0)
32 p
CLK
(1)
(SMOD = 1)
3
(2)
1 1 0 Asynchronous 11 bits Timer 1 or 2 Baud Rate Equation
3
(2)
1 1 1 Asynchronous with Multiprocessor Communication
(4)
11 bits Timer 1 or 2 Baud Rate Equation
(1)
p
CLK
will be equal to t
CLK
, except that p
CLK
will stop for Idle mode.
(2)
For modes 1 and 3, the selection of Timer 1 or 2 for baud rate is specified via the T2CON (C8h) register.
(3)
RI_0 will only be activated when a valid STOP is received.
(4)
RI_0 will not be activated if bit 9 = 0.
REN_0 Receive Enable. This bit enables/disables the serial Port 0 received shift register.
bit 4 0: Serial Port 0 reception disabled.
1: Serial Port 0 received enabled (modes 1, 2, and 3). Initiate synchronous reception (mode 0).
TB8_0 9th Transmission Bit State. This bit defines the state of the 9th transmission bit in serial Port 0 modes 2 and 3.
bit 3
RB8_0 9th Received Bit State. This bit identifies the state of the 9th reception bit of received data in serial Port 0 modes
bit 2 2 and 3. In serial port mode 1, when SM2_0 = 0, RB8_0 is the state of the stop bit. RB8_0 is not used in mode 0.
TI_0 Transmitter Interrupt Flag. This bit indicates that data in the serial Port 0 buffer has been completely shifted out. In serial
bit 1 port mode 0, TI_0 is set at the end of the 8th data bit. In all other modes, this bit is set at the end of the last data bit.
This bit must be manually cleared by software.
RI_0 Receiver Interrupt Flag. This bit indicates that a byte of data has been received in the serial Port 0 buffer. In serial
bit 0 port mode 0, RI_0 is set at the end of the 8th bit. In serial port mode 1, RI_0 is set after the last sample of the incoming
stop bit subject to the state of SM2_0. In modes 2 and 3, RI_0 is set after the last sample of RB8_0. This bit must
be manually cleared by software.
Serial Data Buffer 0 (SBUF0)
7 6 5 4 3 2 1 0 Reset Value
SFR 99h 00h
SBUF0 Serial Data Buffer 0. Data for Serial Port 0 is read from or written to this location. The serial transmit and receive
bits 7−0 buffers are separate registers, but both are addressed at this location.