Maxim Integrated 71M6521BE Energy Meter IC Family Software - Manual (Page 121)

71M652X Software User’s Guide
Revision 1.7 TERIDIAN Proprietary 121 of 138
© Copyright 2005-2007 TERIDIAN Semiconductor Corporation
Timer/Counter Mode Control Register (TMOD)
MSB LSB
GATE C/T M1 M0 GATE C/T M1 M0
Timer 1 Timer 0
Table 6-21: The TMOD Register
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 C/T 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.
TMOD.5
TMOD.1 M1 Selects the mode for Timer/Counter 0 or Timer/Counter 1, as shown in TMOD
description.
TMOD.4
TMOD.0 M0 Selects the mode for Timer/Counter 0 or Timer/Counter 1, as shown in TMOD
description.
Table 6-22: The TMOD Register Bits Description
M1 M0 Mode Function
0 0 Mode 0 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 Mode 1 16-bit Counter/Timer.
1 0 Mode 2 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 Mode 3 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 6-23: Timers/Counters Mode Description
Note: In Mode 3, TL0 is affected by TR0 and gate control bits, and sets TF0 flag on overflow, while
TH0 is affected by TR1 bit, and the TF1 flag is set on overflow.
Timer/Counter Control Register (TCON)
MSB LSB
TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0
Table 6-24: The TCON Register