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7 I/O PORTS (PPORT)
If the CLGOSC.xxxxSLPC bit for the CLK_PPORT clock source is 1, the CLK_PPORT clock source is deacti-
vated during SLEEP mode and it disables the chattering filter function regardless of the PPORTPxCHATEN.Px-
CHATENy bit setting (chattering filter enabled/disabled).
7.3.3 Clock Supply During Debugging
The CLK_PPORT supply during debugging should be controlled using the PPORTCLK.DBRUN bit.
The CLK_PPORT supply to PPORT is suspended when the CPU enters debug state if the PPORTCLK.DBRUN
bit = 0. After the CPU returns to normal operation, the CLK_PPORT supply resumes. The PPORT chattering filter
stops operating when the CLK_PPORT supply is suspended. If the chattering filter is enabled in PPORT, the input
port function is also deactivated. However, the control registers can be altered. If the PPORTCLK.DBRUN bit = 1,
the CLK_PPORT supply is not suspended and the chattering filter will keep operating in a debug state.
7.4 Operations
7.4.1 Initialization
After a reset, the ports except for the debugging function are configured as shown below.
• Port input:
Disabled
• Port output:
Disabled
• Pull-up:
Off
• Pull-down:
Off
• Port pins:
High impedance state
• Port function: Configured to GPIO
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
(Disable input)
(Disable output)
(Disable peripheral I/O function)
(Select peripheral I/O function)
(Enable peripheral I/O function)
(Enable output)
(Enable GPIO function)
Seiko Epson Corporation
S1C31D50/D51 TECHNICAL MANUAL
(Rev. 2.00)
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