71M6511-IGT TERIDIAN [Teridian Semiconductor Corporation], 71M6511-IGT Datasheet - Page 31

• Manufacturer Part Number: 71M6511-IGT
• Description: Single-Phase Energy Meter IC
• Manufacturer: TERIDIAN [Teridian Semiconductor Corporation]

Timer/Counter Control register (TCON)
Interrupt Request register (IRCON)
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).
External Interrupts
The external interrupts are connected as shown in Table 44. The polarity 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 interrupts 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 44.
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 that is set by the interrupt hardware and is reset automatically by the MPU interrupt handler (0 through 5).
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Bit
Bit
IRCON.7
IRCON.6
IRCON.5
IRCON.4
IRCON.3
IRCON.2
IRCON.1
IRCON.0
TCON.7
TCON.6
TCON.5
TCON.4
TCON.3
TCON.2
TCON.1
TCON.0
MSB
MSB
Symbol
Symbol
IEX6
IEX5
IEX4
IEX3
IEX2
TR1
TR0
TF1
TF0
IE1
IT1
IE0
IT0
-
-
-
TF1
Function
Timer 1 overflow flag
Not used for interrupt control
Timer 0 overflow flag
Not used for interrupt control
External interrupt 1 flag
External interrupt 1 type control bit
External interrupt 0 flag
External interrupt 0 type control bit
Function
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
TR1
© 2005-2007 TERIDIAN Semiconductor Corporation
EX6
Table 43: The IRCON Bit Functions
Table 41: The TCON Bit Functions
TF0
Table 42: The IRCON Register
Table 40: The TCON Register
IEX5
TR0
IEX4
IE1
Single-Phase Energy Meter IC
IT1
IEX3
71M6511/71M6511H
DATA SHEET
IE0
IEX2
LSB
LSB
IT0
AUGUST 2007
V2.6