HD404019R Datasheet, PDF (19/65 Pages) Renesas Technology Corp – CMOS 4-bit single-chip microcomputers

HD404019R Series
Interrupt Enable Flag (IE: $000, Bit 0): The interrupt enable flag enables/disables interrupt requests as
shown in table 3. It is reset by an interrupt and set by the RTNI instruction.
Table 3 Interrupt Enable Flag
IE
Interrupt Enable/Disable
0
Disabled
1
Enabled
External Interrupts (INT₀, INT₁): The external interrupt request inputs (INT₀, INT₁) can be selected by
the port mode register (PMR: $004). Setting bit 3 and bit 2 of PMR causes the R3₃/INT₁ and R3₂/INT₀ pins
to be used as INT₁ and INT₀, respectively.
The external interrupt request flags (IF0, IF1) are set at the falling edge of the INT₀ and INT₁ inputs. (Refer
to table 4.)
The INT₁ input can be used as a clock signal input to timer B in which timer B counts up at each falling
edge of the INT₁ input. When INT₁ is used as the timer B external event input, the external interrupt mask
(IM1) has to be set so that the interrupt request by INT₁ will not be accepted. (Refer to table 5.)
Table 4 External Interrupt Request Flags
IF0, IF1
0
1
Interrupt Request
No
Yes
Table 5
IM0, IM1
0
1
External Interrupt Masks
Interrupt Request
Enabled
Disabled (masked)
External Interrupt Request Flags (IF0: $000, Bit 2; IF1: $001, Bit 0): The external interrupt request
flags (IF0, IF1) are set at the falling edge of the INT₀ and INT₁ inputs, respectively.
External Interrupt Masks (IM0: $000, Bit 3; IM1: $001, Bit 1): The external interrupt masks mask the
external interrupt requests.
Port Mode Register (PMR: $004): The port mode register is a 4-bit write-only register which controls the
R3₂/INT₀ pin, R3₃/INT₁ pin, R4₁/SI pin, and R4₂/SO pin as shown in table 6. The port mode register will be
initialized to $0 by MCU reset. These pins are therefore initially used as ports.
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