Maxim Integrated High-Speed Microcontroller Users Guide: DS80C390 Supplement - Manual (Page 29)

High-Speed Microcontroller User’s Guide: DS80C390 Supplement
29 of 158
TB8_0
Bit 3 9th Transmission Bit State. This bit defines the state of the 9th transmission bit
in serial port 0 modes 2 and 3.
RB8_0
Bit 2 9th Received Bit State. This bit identifies that state of the 9th reception bit of
received data in serial port 0 modes 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
Bit 1 Transmitter Interrupt Flag. This bit indicates that data in the serial port 0
buffer has been completely shifted out. In serial 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
Bit 0 Receiver Interrupt Flag. This bit indicates that a byte of data has been received
in the serial port 0 buffer. In serial 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
SFR 99h SBUF0.7 SBUF0.6 SBUF0.5 SBUF0.4 SBUF0.3 SBUF0.2 SBUF0.1 SBUF0.0
RW-0 RW-0 RW-0 RW-0 RW-0 RW-0 RW-0 RW-0
R = Unrestricted Read, W = Unrestricted Write, -n = Value after Reset
SBUF0.7-0
Bits 7-0 Serial Data Buffer 0. Data for serial port 0 is read from or written to this
location. The serial transmit and receive buffers are separate registers, but both
are addressed at this location.
REVISION ID REGISTER (RID)
7 6 5 4 3 2 1 0
SFR 9Ah
R-* R-* R-* R-* R-* R-* R-* R-*
* = See description
RID
Bits 7-0 Revision Identification. This register indicates the revision level of the die. This
number is read-only and is fixed at the time of manufacture. The register value is
read as a two-digit hexadecimal number that corresponds to the die revision as
follows:
REGISTER
VALUE
DIE REVISION
FF All Ax and Bx revisions
C1 Revisions C1 and C2
C3 Revision C3
Cx Revision Cx (and so on)