Fujitsu FR81S User Manual
CHAPTER 40: MULTI-FUNCTION SERIAL INTERFACE
4. Registers
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : MULTI-FUNCTION SERIAL INTERFACE
FUJITSU SEMICONDUCTOR CONFIDENTIAL
66
Notes:
⋅
These bits can be changed only when transmission and reception are disabled (SCR:TXE=RXE="0").
⋅
In the slave mode (SCR:MS="1"), setting these bits has no effect.
⋅
Settings other than those listed above are prohibited.
[bit5] CSLVL: Serial chip select level setting bit
This bit is used to select "H" or "L" for the level when a serial chip select pin is inactive.
This bit is used for communication of a chip select pin.
CSLVL
Serial chip select level setting bit
0
Inactive level set to "L"
1
Inactive level set to "H"
Notes:
⋅
This bit can be changed only when transmission and reception are disabled (SCR:TXE=RXE="0").
⋅
Setting this bit is used under one of the following conditions:
⋅
Slave mode (SCR:MS="0")
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Data format of chip select is disabled (ESCR:CSFE="0")
⋅
Data format of chip select is enabled (ESCR:CSFE="1") and a serial chip select pin is active
[bit4 to bit1] CSEN3-0: Serial chip select enable bits
These bits are used to enable or disable each serial chip select pin.
CSEN3 bit corresponds to SCS3 pin, CSEN2 bit to SCS2 pin, CSEN1 bit to SCS1 pin, and CSEN0 bit to
SCS0 pin.
In the slave mode (SCR:MS="1"), only CSEN0 bit is used to enable or disable a serial chip pin.
CSEN
Serial chip select enable bit
0
Operation of a serial chip select pin disabled
1
Operation of a serial chip select pin enabled
Notes:
⋅
These bits can be changed only when transmission and reception are disabled (SCR:TXE=RXE="0").
⋅
In the master mode (SCR:MS="0"), if CSEN3-0 are set to "0000b", transmission/reception operation will
be performed regardless of a serial chip select pin.
⋅
In the slave mode (SCR:MS="1"), if CSEN0 is set to "0", transmission/reception operation will be
performed regardless of a serial chip select pin.
[bit0] CSOE: Serial chip select output enable bit
This bit is used to enable or disable output of serial chip select pins.
CSOE
Serial chip select output enable bit
0
Output of all serial chip select pins disabled
1
Output of all serial chip select pins enabled
Notes:
⋅
This bit can be changed only when transmission and reception are disabled (SCR:TXE=RXE="0").
⋅
In the slave mode (SCR:MS="1"), set this bit to "0".
MB91520 Series
MN705-00010-1v0-E
1379