Fujitsu MB90460 Series, Руководство по оборудованию

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CHAPTER 17 UART
Table 17.4-2 Serial Mode Register (SMR0/SMR1)
Bit name Function
bit7,
bit6
MD1, MD0: Operation
mode selection bits
•
These bits select an operation mode.
(Note)
Operation mode 1 (multiprocessor mode) can be used only from the master
system during master-slave communication. UART cannot be used from the
slave system because it has no address/data detection function during reception.
bit5
to
bit3
CS2 to CS0:
Clock selection bits
•
These bits select the baud rate clock source. When the dedicated baud rate
generator is selected, the baud rate is determined by the value of these bits.
•
When the dedicated baud rate generator is selected, six baud rates can be
selected for asynchronous/synchronous transfer mode. With the baud rate
generated by internal and external timer, there are totally eight baud rate
selections.
•
Input clocks can be selected from external clocks (SCK0/SCK1 pin), 16-bit
reload timer 0, and the dedicated baud rate generator.
bit2
RST:
UART reset bit
•
Writing "0" to this bit has no effect.
•
Writing "1" to this bit resets the UART.
•
Always read as "0".
bit1
SCKE:
Serial clock output
enable bit
•
This bit controls the serial clock input-output ports.
•
When this bit is "0", the P42/SCK0 and P62/SCK1 pins operate as general input-
output ports (P42 and P62) or serial clock input pins. When this bit is "1", the
pins operate as serial clock output pins.
(Note)
•
When using the P42/SCK0 and P62/SCK1 pins as serial clock input (SCKE =
0) pins, set the P40 and P62 as input ports. Also, select external clocks
(SMR0/SMR1: CS2 to CS0 = 111
B
) using the clock selection bits.
•
When using the pins as serial clock output (SCKE = 1) pins, select clocks
other than external clocks (other than SMR0/SMR1: CS2 to CS0 = 111
B
).
(Reference)
When the SCK0/SCK1 pin is assigned to serial clock output (SCKE = 1), it
functions as the serial clock output pin regardless of the status of the general
input-output ports.
bit0
SOE:
Serial data output
enable bit
•
This bit enables or disables the output of serial data.
•
When this bit is "0", the P41/SOT0 and P61/SOT1 pins operate as general input-
output ports (P41 and P61). When this bit is "1", the P41/SOT0 and P61/SOT1
pins operate as serial data output pins (SOT0/SOT1).
(Reference)
When serial data is output (SOE = 1), the enabled, the P41/SOT0 and P61/SOT1
pins function as SOT0/SOT1 pins regardless of the status of general input-
output ports (P41 and P61).