Maxim Integrated 71M6521BE Energy Meter IC Family Software - Manual (Page 130)

71M652X Software User’s Guide
Revision 1.7 TERIDIAN Proprietary 130 of 138
© Copyright 2005-2007 TERIDIAN Semiconductor Corporation
Timer/Counter Control Register (TCON)
MSB LSB
TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0
Table 6-47: The TCON Register
Bit Symbol Function
TCON.7 TF1 Timer 1 overflow flag
TCON.6 TR1 Not used for interrupt control
TCON.5 TF0 Timer 0 overflow flag
TCON.4 TR0 Not used for interrupt control
TCON.3 IE1 External interrupt 1 flag
TCON.2 IT1 External interrupt 1 type control bit
TCON.1 IE0 External interrupt 0 flag
TCON.0 IT0 External interrupt 0 type control bit
Table 6-48: The TCON Bit Functions
Interrupt Request Register (IRCON)
MSB LSB
IEX6 IEX5 IEX4 IEX3 IEX2
Table 6-49: The IRCON Register
Bit Symbol Function
IRCON.7 -
IRCON.6 -
IRCON.5 IEX6 External interrupt 6 edge flag
IRCON.4 IEX5 External interrupt 5 edge flag
IRCON.3 IEX4 External interrupt 4 edge flag
IRCON.2 IEX3 External interrupt 3 edge flag
IRCON.1 IEX2 External interrupt 2 edge flag
IRCON.0 -
Table 6-50: The IRCON Bit Functions
Note: 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).
6.3.5.3 External Interrupts
The 71M6521 MPU allows seven external interrupts. These are connected as shown in Table 46. The direction of
interrupts 2 and 3 is programmable in the MPU. Interrupts 2 and 3 should be programmed for falling sensitivity, using
the I2FR and I3FR bits of the T2CON register (see Table 6-50).