897Chapter 20 Port FunctionsUser’s Manual U16580EE3V1UD0020.3 Port Pin Functions20.3.1 Port 0Port 0 is a 5-bit input only port.(1) Functions• Input data can be read in 1-bit units by using the port register 0 (P0).• The alternate functions shared with the input port functionality of port 0 are always enabled.Table 20-4: Alternate Function Pins and Port Types of Port 0(2) Control registers(a) Port register 0 (P0)The port register 0 (P0) is an 8-bit register that reflects the input levels of port pins P00 to P04.This register is read-only in 8-bit or 1-bit units.Reset input causes an undefined register content.Figure 20-23: Port Register 0 (P0)Remark: n = 0 to 4Port Alternate Function Remark Port TypePort 0 P00 NMI Non maskable interrupt 3P01 INTP0,ESO0External interrupt request input,Emergency output shut off input (TMR0)15AP02 INTP1,ESO1External interrupt request input,Emergency output shut off input (TMR1)P03 INTP2,ADTRG0External interrupt request input,External A/D conversion start trigger (ADC0)15P04 INTP3,ADTRG1External interrupt request input,External A/D conversion start trigger (ADC1)After reset: Undefined R Address: FFFFF400H7 6 5 4 3 2 1 0P0 0 0 0 P04 P03 P02 P01 P00P0n Input Data Control of Pin P0n0 Low level is input1 High level is input
