Fujitsu MB90390 Series Hardware Manual page 381

Table 20.4-2 Bit Function of the Serial Mode Register (SMR2/SMR3)
Bit name
MD1 and MD0:
bit7
Operation mode
bit6
selection bits
OTO:
bit5 One-to-one external
clock selection bit
EXT:
bit4 External clock
selection bit
REST:
Restart of
bit3
transmission reload
counter bit
UPCL:
UART2, UART3
bit2
programmable clear
bit (Software reset)
SCKE:
bit1 Serial clock output
enable
SOE:
bit0 Serial data output
enable bit
These two bits set the UART2, UART3 operation mode.
This bit sets an external clock directly to the LIN-UART2, LIN-UART3's serial clock.
This function is used for operating mode 2 (synchronous) slave mode operation.
This bit executes internal or external clock source for the reload counter
If a "1" is written to this bit the reload counter is restarted. Writing "0" to it has no
effect. Reading from this bit always returns "0".
Writing a "1" to this bit resets LIN-UART2, UART3 immediately. The register settings
are preserved. Possible reception or transmission will cut off.
All flags (TDRE, RDRF, LBD, PE, ORE, FRE) are cleared and the Reception Data
Register (RDR2/RDR3) contains "00
from it always returns "0".
LIN-UART2, UART3 reset should be performed after disabling the interrupt enable bits.
• This bit controls the serial clock I/O ports.
• When this bit is "0", SCK2/SCK3 pin operate as general purpose I/O port or serial
clock input pin. When this bit is "1", the pin operates as serial clock output pin and
outputs clock in operating mode 2 (synchronous). SCKE bit is fixed to "0" for
MS=1.
Note:
When using SCK2/SCK3 pin as serial clock input (SCKE=0) pin, set the
corresponding bit of DDR as input port. Also, select external clock (EXT = 1) using
the external clock selection bit.
Reference:
When the SCK2/SCK3 pin is assigned to serial clock output (SCKE=1), it functions
as the serial clock output pin regardless of the status of the general purpose I/O
ports.
• This bit enables or disables the output of serial data.
• When this bit is "0", SOT2/SOT3 pin operates as general purpose I/O pin. When this
bit is "1", SOT2/SOT3 pin operates as serial data output pins (SOT2/SOT3).
Reference:
When the output of serial data is enabled (SOE=1), SOT2/SOT3 pin functions as
serial data output pin (SOT2/SOT3) regardless of the status of general input-output
ports.
CHAPTER 20 UART2, UART3
Function
". Writing "0" to this bit has no effect. Reading
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