Datasheet

Section 9 Peripheral I/O Mapping Controller
Page 270 of 982 REJ09B0465-0300 Rev. 3.00
Sep 17, 2010
H8S/20103, H8S/20203, H8S/20223, H8S/20115, H8S/20215, H8S/20235 Group
9.2 Usage Notes
9.2.1 Procedures for Setting Multiplexed Port Functions
Use the following procedures to set a function for a multiplexed port.
1. Clear the relevant port mode register (PMR) bit to 0 to select the general input function.
2. Set PMCWPR to enable writing to the relevant peripheral function mapping register (PMCR).
3. Select a function using the peripheral function mapping register (PMCR).
4. Set the PMCRWE bit in PMCWPR to 0 to disable writing to PMCR.
5. Set the PMR bit to 1 as necessary to activate the selected multiplexed function.
9.2.2 Notes on Setting PMC Registers
1. A function of a multiplexed port should be set when the relevant PMR bit is 0. If a function is
set when PMR is 1, an unintended edge may be input for the input function or unintended
pulses may be output for the output function.
2. Only the functions that can be selected by PMCR should be set. If the other functions are set,
operation cannot be guaranteed.
3. The same function must not be assigned to multiple pins by the PMC.
4. Port A also has an analog input function for the A/D converter. When port A is used as analog
input, the relevant bit in PMRA should be set to 0 to select general I/O.