Epson S1C17W22 Technical Manual page 76

6 I/O PORTS (PPORT)
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 PxIOEN register bits:
- Set the PxIOEN.PxIENy bit to 0.
- Set the PxIOEN.PxOENy bit to 0.
2. Set the PxMODSEL.PxSELy bit to 0.
3. Initialize the peripheral circuit that uses the pin.
4. Set the PxFNCSEL.PxyMUX[1:0] bits. (Select peripheral I/O function)
5. Set the PxMODSEL.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 PxIOEN.PxOENy bit to 1.
2. Set the PxMODSEL.PxSELy bit to 0.
Initial settings when using a port as a general-purpose input port
(only for the ports with GPIO function)
When using the Pxy port pin as a general-purpose input pin, perform the following software initial settings:
1. Write 0 to the PxINTCTL.PxIEy bit. * (Disable interrupt)
2. When using the chattering filter, configure the PPORT operating clock (see "PPORT Operating Clock") and
set the PxCHATEN.PxCHATENy bit to 1. *
When the chattering filter is not used, set the PxCHATEN.PxCHATENy bit to 0 (supply of the PPORT op-
erating clock is not required).
3. Configure the following PxRCTL register bits when pulling up/down the port using the internal pull-up or
down resistor:
- PxRCTL.PxPDPUy bit
- Set the PxRCTL.PxRENy bit to 1.
Set the PxRCTL.PxRENy bit to 0 if the internal pull-up/down resistors are not used.
4. Set the PxMODSEL.PxSELy bit to 0. (Enable GPIO function)
5. Configure the following bits when using the port input interrupt: *
- Write 1 to the PxINTF.PxIFy bit.
- PxINTCTL.PxEDGEy bit
- Set the PxINTCTL.PxIEy bit to 1.
6. Set the following PxIOEN register bits:
- Set the PxIOEN.PxOENy bit to 0.
- Set the PxIOEN.PxIENy bit to 1.
* Steps 1 and 5 are required for the ports with an interrupt function. Step 2 is required for the ports with a chat-
tering filter function.
Table 6.4.1.1 lists the port status according to the combination of data input/output control and pull-up/down
control.
6-4
(Disable input)
(Disable output)
(Disable peripheral I/O function)
(Enable peripheral I/O function)
(Enable output)
(Enable GPIO function)
(Select pull-up or pull-down resistor)
(Enable pull-up/down)
(Clear interrupt flag)
(Select interrupt edge (input rising edge/falling edge))
(Enable interrupt)
(Disable output)
(Enable input)
Seiko Epson Corporation
S1C17W22/W23 TECHNICAL MANUAL
(Rev. 1.3)