SM59R16A5/SM59R09A5/SM59R05A5
8-Bit Micro-controller
64KB/36KB/20KB with ISP Flash
& 2KB RAM embedded
Fig. 9-8: Receive mode A for Serial 1
9.2.2. Mode B
This mode is similar to Mode 1 of Serial interface 0. Pin RXD1 serves as input, and TXD1 serves as serial output. No
external shift clock is used. 10 bits are transmitted: a start bit (always 0), 8 data bits (LSB first), and a stop bit (always 1).
On receive, a start bit synchronizes the transmission, 8 data bits are available by reading S1BUF, and stop bit sets the
flag RB81 in the SFR S1CON. In mode B, internal baud rate generator is use to specify the baud rate.
Fig. 9-9: Transmit mode B for Serial 1
Fig. 9-10: Receive mode B for Serial 1
Multiprocessor communication of Serial Interface 0 and 1
9.3.
The feature of receiving 9 bits in Modes 2 and 3 of Serial Interface 0 or in Mode A of Serial Interface 1 can be used for
multiprocessor communication. In this case, the slave processors have bit SM20 in S0CON or SM21 in S1CON set to 1.
When the master processor outputs slave’s address, it sets the Bit 9 to 1, causing a serial port receive interrupt in all the
slaves. The slave processors compare the received byte with their network address. If matched, the addressed slave
will clear SM20 or SM21 and receive the rest of the message, while other slaves will leave SM20 or SM21 bit unaffected
and ignore this message. After addressing the slave, the host will output the rest of the message with the Bit 9 set to 0, so
no serial port receive interrupt will be generated in unselected slaves.
9.4.
Baud rate generator
9.4.1. Serial interface 0 modes 1 and 3
(a) When BRGS = 0 (in SFR AUX):
2SMOD × FOSC
32×12× 256 − TH1
Baud Rate =
(
)
(b) When BRGS = 1 (in SFR AUX):
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M047 46 Ver.G SM59R16A5 01/2014
SYNCMOS [ SYNCMOS TECHNOLOGIES,INC ]
