VMX1C1016 Datasheet, PDF (36/76 Pages) List of Unclassifed Manufacturers – Versa Mix 8051 Mixed-Signal MCU

VMX51C1016
Serial UART Interfaces
The VMX51C1016 includes two serial UART
interface ports (UART0 and UART1). Each serial
port has a 10-bit timer devoted to baud rate
generation.
Both serial ports can operate in full duplex
asynchronous mode. The VMX51C1016 also
includes a double buffer, enabling the UART to
accept an incoming word before the software
has read the previous value.
UART0 Serial Interface
The operation of the UART0 on the
VMX51C1016 is similar to a standard 8051
UART.
UART0 can derive its clock source from a 10-bit
dedicated baud rate generator or from the Timer
1 overflow.
UART0 transmit and receive buffers are
accessed through a unique SFR register
(S0BUF).
UART0 S0BUF has a double buffering feature
on reception, which allows the UART to accept
an incoming word before the software has read
the previous value from the S0BUF.
TABLE 61: (S0BUF) SERIAL PORT 0, DATA BUFFER - SFR 99H
7
6
5
4
3
2
1
0
S0BUF [7:0]
UART0 Control Register
UART0 configuration is performed mostly via the
S0CON SFR register located at address 98h.
TABLE 62: (S0CON) SERIAL PORT 0, CONTROL REGISTER - SFR 98H
7
6
5
4
S0M0
S0M1
MPCE0
R0EN
3
2
1
0
T0B8
R0B8
T0I
R0I
Bit Mnemonic Function
7
S0M0
Sets Serial Port Operating Mode
6
S0M1
See Table
5
MPCE
1 = Enables the multiprocessor
communication feature.
4
R0EN
1 = Enables serial reception.
Cleared by software to disable
3
T0B8
reception.
The 9^th transmitted data bit in Modes
2 and 3. Set or cleared by the CPU,
depending on the function it
performs (parity check,
2
R0B8
multiprocessor communication etc.)
In Modes 2 and 3, it is the 9^th data bit
received. In Mode 1, if sm20 is 0,
RB80 is the stop bit. In Mode 0, this
bit is not used. Must be cleared by
software.
1
T0I
Transmit interrupt flag set by
hardware after completion of a serial
reception. Must be cleared by
software.
0
R0I
Receive interrupt flag set by
hardware after completion of a serial
reception. Must be cleared by
software.
UART0 Operating Modes
UART0 can operate in four distinct modes,
which are defined by the SM0 and SM1 bits of
the S0CON register (see the following table):
TABLE 63: SERIAL PORT 0 MODES
SM0 SM1 MODE DESCRIPTION BAUD RATE
0
0
0
Shift Register
Fosc/12
0
1
1
8-bit UART
Variable
1
0
2
9-bit UART Fclk/32 or /64
1
1
3
9-bit UART
Variable
**Note that the speed in mode 2 depends on SMOD bit in the Special
Function Register PCON when SMOD = 1 fclk/32
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