145User’s Manual U16580EE3V1UD00Chapter 4 Bus Control Function (μPD70F3187 only)The μPD70F3187 is provided with an external bus interface function by which external memories, suchas ROM and RAM, and external I/O can be connected. The μPD70F3447 is not equipped external businterface function.4.1 Features• 32-bit/16-bit/8-bit data bus sizing function• 8 chip areas select function• 4 chip area select signals externally available (CS0, CS1, CS3 and CS4)• Wait function- Programmable wait function, capable of inserting up to 7 wait states for each memory block- External wait function via WAIT pin• Idle state insertion function• External device connection can be enabled via bus control/port alternate function pins• Programmable Endian format (Little Endian/Big Endian)4.2 Bus Control PinsThe following pins are used for connecting to external devices.Note: Even if the port mode control registers for the μPD70F3447 exist, it is prohibited to write othervalues to these registers than the reset values.Bus Control Pin(Function when in Control Mode)Function when in Port Mode Register for Port/Control Mode SwitchingNoteData bus (D0 to D15) PDL0 to PDL15 (Port DL) PMCDLData bus (D16 to D31) PDH0 to PDH15 (Port DH) PMCDHAddress bus (A0 to A15) PAL0 to PAL15 (Port AL) PMCALAddress bus (A16 to A21) PAH0 to PAH5 (Port AH) PMCAHChip select (CS0, CS1, CS3 and CS4) PCS0, PCS1, PCS3 and PCS4(Port CS)PMCCSRead/write control (RD,WR) PCT4, PCT5 (Port CT) PMCCTByte enable control (BE0 to BE3) PCD2 to PCD5 (Port CD) PMCCDExternal wait control (WAIT) PCM0 (Port CM) PMCCM
