71M6511/71M6511H
Single-Phase Energy Meter IC
DATA SHEET
AUGUST 2007
Bit
Symbol
Function
TMOD.7
TMOD.3
Gate
If set, enables external gate control (pin int0 or int1 for Counter 0 or 1,
respectively). When int0 or int1 is high, and TRX bit is set (see TCON register), a
counter is incremented every falling edge on t0 or t1 input pin
TMOD.6
TMOD.2
TMOD.5
TMOD.1
TMOD.4
TMOD.0
C/T
M1
M0
Selects Timer or Counter operation. When set to 1, a Counter operation is
performed. When cleared to 0, the corresponding register will function as a Timer.
Selects the mode for Timer/Counter 0 or Timer/Counter 1, as shown in TMOD
description.
Selects the mode for Timer/Counter 0 or Timer/Counter 1, as shown in TMOD
description.
Table 20: TMOD Register Bit Description
M1
0
M0
0
Mode
Mode 0
Function
13-bit Counter/Timer with 5 lower bits in the TL0 or TL1 register and the
remaining 8 bits in the TH0 or TH1 register (for Timer 0 and Timer 1,
respectively). The 3 high order bits of TL0 and TL1 are held at zero.
0
1
1
0
Mode 1
Mode2
16-bit Counter/Timer.
8-bit auto-reload Counter/Timer. The reload value is kept in TH0 or TH1,
while TL0 or TL1 is incremented every machine cycle. When TL(x)
overflows, a value from TH(x) is copied to TL(x).
1
1
Mode3
If Timer 1 M1 and M0 bits are set to '1', Timer 1 stops. If Timer 0 M1 and M0
bits are set to '1', Timer 0 acts as two independent 8-bit Timer/Counters.
Table 21: Timers/Counters Mode Description
Note:
TL0 is affected by TR0 and gate control bits, and sets TF0 flag on overflow.
TH0 is affected by TR1 bit, and sets TF1 flag on overflow.
Timer/Counter Control Register (TCON)
MSB
LSB
IT0
TF1
TR1
TF0
TR0
IE1
IT1
IE0
Table 22: The TCON Register
Page: 25 of 95
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