78M6612 Data Sheet
DS_6612_001
Interrupt Request Register (IRCON)
Table 29: The IRCON Register
MSB
LSB
–
–
EX6
IEX5
IEX4
IEX3
IEX2
–
Bit
Symbol Function
IRCON[7]
IRCON[6]
IRCON[5]
IRCON[4]
IRCON[3]
IRCON[2]
IRCON[1]
IRCON[0]
–
–
IEX6
IEX5
IEX4
IEX3
IEX2
–
External interrupt 6 edge flag.
External interrupt 5 edge flag.
External interrupt 4 edge flag.
External interrupt 3 edge flag.
External interrupt 2 edge flag.
Only TF0 and TF1 (timer 0 and timer 1 overflow flag) will be automatically cleared by hardware
when the service routine is called (Signals T0ACK and T1ACK – port ISR – active high when
the service routine is called).
1.4.9.2 External Interrupts
The 78M6612 MPU allows seven external interrupts. These are connected as shown in Table 30. The
direction of interrupts 2 and 3 is programmable in the MPU. Interrupts 2 and 3 should be programmed
for falling sensitivity. The generic 8051 MPU literature states that interrupt 4 through 6 are defined as
rising edge sensitive. Thus, the hardware signals attached to interrupts 5 and 6 are inverted to achieve
the edge polarity shown in Table 30.
Table 30: External MPU Interrupts
External
Interrupt
Flag
Reset
Connection
Polarity
0
1
2
3
4
5
6
Digital I/O High Priority
Digital I/O Low Priority
FWCOL0, FWCOL1
see DIO_Rx
see DIO_Rx
falling
automatic
automatic
automatic
automatic
automatic
automatic
manual
CE_BUSY
falling
PLL_OK (rising), PLL_OK (falling)
EEPROM busy
rising
falling
XFER_BUSY OR RTC_1SEC
falling
FWCOLx interrupts occur when the CE collides with a Flash write attempt. See the Flash write
description in Section 1.5.5 for more detail.
SFR (special function register) enable bits must be set to permit any of these interrupts to occur.
Likewise, each interrupt has its own flag bit, which is set by the interrupt hardware, and reset by the MPU
interrupt handler. Note that XFER_BUSY, RTC_1SEC, FWCOL0, FWCOL1, PLLRISE, PLLFALL, have
their own enable and flag bits in addition to the interrupt 6, 4, and 2 enable and flag bits.
34
Rev. 1.2
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
