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7.4. Operations
7.4.1. Initialization
After a reset, the ports except for the debugging function are configured as shown below.
•
Port input:
•
Port output:
•
Pull-up:
•
Pull-down:
•
Port pins:
•
Port function:
This status continues until the ports are configured via software. The debugging function ports are
configured for debug signal input/output.
Initial settings when using a port for a peripheral I/O function
When using the Pxy port for a peripheral I/O function, perform the following software initial settings:
1. Set the following PPORTPxIOEN register bits:
Set the PPORTPxIOEN.PxIENy bit to 0.
-
Set the PPORTPxIOEN.PxOENy bit to 0.
-
2. Set the PPORTPxMODSEL.PxSELy bit to 0.
3. Initialize the peripheral circuit that uses the pin.
4. Set the PPORTPxFNCSEL.PxyMUX[1:0] bits.
5. Set the PPORTPxMODSEL.PxSELy bit to 1.
For the list of the peripheral I/O functions that can be assigned to each port of this IC, refer to
"Control Register and Port Function Configuration of this IC." For the specific information on the
peripheral I/O functions, refer to the respective peripheral circuit chapter.
Initial settings when using a port as a general-purpose output port
(only for the ports with GPIO function)
When using the Pxy port pin as a general-purpose output pin, perform the following software initial
settings:
1. Set the PPORTPxIOEN.PxOENy bit to 1.
2. Set the PPORTPxMODSEL.PxSELy bit to 0.
7-4
Disabled
Disabled
Off
Off
High impedance state
Configured to GPIO
Seiko Epson Corporation
(Disable input)
(Disable output)
(Disable peripheral I/O function)
(Select peripheral I/O function)
(Enable peripheral I/O function)
(Enable output)
(Enable GPIO function)
S1C31D50 TECHNICAL MANUAL
(Rev. 1.00)
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