M16C User Manual.pdf

External ROMMitsubishi microcomputersM16C / 62 GroupSINGLE-CHIP 16-BIT CMOS MICROCOMPUTERTable 6.2.2. Pin Description (2)Pin name Signal name I/O typeFunctionWRL / WR,WRH / BHE,RD,BCLK,HLDA,HOLD,ALE,RDYWRL / WR,WRH / BHE,RD,BCLK,HLDA,HOLD,ALE,RDYOutputOutputOutputOutputOutputInputOutputInputOutput WRL, WRH (WR and BHE), RD, BCLK, HLDA, and ALEsignals. WRL and WRH, and BHE and WR can be switched usingsoftware control.WRL, WRH, and RD selecteWith a 16-bit external data bus, data is written to even addresseswhen the WRL signal is “L” and to the odd addresses when the WRHsignal is “L”. Data is read when RD is “L”.WR, BHE, and RD selectedData is written when WR is “L”. Data is read when RD is “L”. Oddaddresses are accessed when BHE is “L”. Use this mode when usingan 8-bit external data bus.While the input level at the HOLD pin is “L”, the microcomputer isplaced in the hold state. While in the hold state, HLDA outputs a “L"level. ALE is used to latch the address. While the input level of theRDY pin is “L”, the microcomputer is in the ready state.P60 to P67I/O port P6Input/outputThis is an 8-bit I/O port equivalent to P1. The port can be set to have ornot have a pull-up resistor in units of four bits by software. Pins in thisport also function as UART0 and UART1 I/O pins as selected bysoftware.P70 to P77I/O port P7Input/outputThis is an 8-bit I/O port equivalent to P6. Pins in this port also functionas timer A0–A3, timer B5, or UART2 I/O pins as selected by software.P80 to P84,P86,P87,P85I/O port P8I/O port P85Input/outputInput/outputInput/outputInputP80 to P84, P86, and P87 are I/O ports with the same functions as P6.Using software, they can be made to function as the I/O pins for timerA4 and the input pins for external interrupts. P86 and P87 can be setusing software to function as the I/O pins for a sub clock generationcircuit. In this case, connect a quartz oscillator between P86 (XCOUTpin) and P87 (XCIN pin). P85 is an input-only port that also functionsfor NMI. The NMI interrupt is generated when the input at this pinchanges from “H” to “L”. The NMI function cannot be canceled usingsoftware. The pull-up cannot be set for this pin.P90 to P97I/O port P9Input/outputThis is an 8-bit I/O port equivalent to P6. Pins in this port also functionas SI/O3,4 I/O pin, timer B0–B2 input pins, D-A converter output pins,A-D converter’s extended input pins, or A-D trigger input pins asselected by software.P100 to P107I/O port P10Input/outputThis is an 8-bit I/O port equivalent to P6. Pins in this port also functionas A-D converter input pins. Furthermore, P104–P107 also function asinput pins for the key input interrupt function.548