SM59R16A2 Datasheet, PDF (38/67 Pages) SyncMOS Technologies,Inc – 8-Bit Micro-controller

SM59R16A2/SM59R08A2
8-Bit Micro-controller
64KB/32KB ISP Flash & 2KB RAM embedded
Fig. 9-10: Receive mode B for Serial 1
9.3 Multiprocessor communication of Serial Interface 0 and 1
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 BRS = 0 (in SFR BRGS):
Baud
Rate
=
32
2^SMOD × F_OSC
×12 × (256 − TH1)
(b) When BRS = 1 (in SFR BRGS):
( ) ^Baud
Rate
=
64
2^SMOD × F_OSC
× 2¹⁰ − S0REL
9.4.2 Serial interface 1 modes A and B
( ) ^Baud
Rate
=
32 ×
F_OSC
2¹⁰ − S1REL
9.5 Clock source for baud rate
It is not recommended to use the internal OSC as the clock source when the serial interface functions
are used. The reason is that the baud rate in the previous section must be as accurate as possible.
The internal OSC clock frequency may be varied with +5%. So the user can choose the clock
source from external crystal or oscillator.
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M034
38
Ver.B SM59R16A2/SM59R08A2 06/2009