COP8AME9_14 Datasheet, PDF (48/102 Pages) Texas Instruments – COP8AME9 8-Bit CMOS Flash Microcontroller with 8k Memory, Dual Op Amps, Virtual EEPROM, Temperature Sensor, 10-Bit A/D and Brownout Reset

COP8AME9, COP8ANE9
SNOS930F – MARCH 2001 – REVISED MARCH 2013
www.ti.com
The IDLE Timer cannot be started or stopped under software control, and it is not memory mapped, so it cannot
be read or written by the software. Its state upon Reset is unknown. Therefore, if the device is put into the IDLE
mode at an arbitrary time, it will stay in the IDLE mode for somewhere between 30 µs and the selected time
period.
In order to precisely time the duration of the IDLE state, entry into the IDLE mode must be synchronized to the
state of the IDLE Timer. The best way to do this is to use the IDLE Timer interrupt, which occurs on every
underflow of the bit of the IDLE Timer which is associated with the selected window. Another method is to poll
the state of the IDLE Timer pending bit T0PND, which is set on the same occurrence. The Idle Timer interrupt is
enabled by setting bit T0EN in the ICNTRL register.
Any time the IDLE Timer window length is changed there is the possibility of generating a spurious IDLE Timer
interrupt by setting the T0PND bit. The user is advised to disable IDLE Timer interrupts prior to changing the
value of the ITSEL bits of the ITMR Register and then clear the T0PND bit before attempting to synchronize
operation to the IDLE Timer.
As with the HALT mode, it is necessary to program two NOP's to allow clock resynchronization upon return from
the IDLE mode. The NOP's are placed either at the beginning of the IDLE Timer interrupt routine or immediately
following the “enter IDLE mode” instruction.
For more information on the IDLE Timer and its associated interrupt, see the description in TIMER T0 (IDLE
TIMER).
Figure 22. Multi-Input Wake-Up Logic
MULTI-INPUT WAKE-UP
The Multi-Input Wake-up feature is used to return (wake-up) the device from either the HALT or IDLE modes.
Alternately Multi-Input Wake-up/Interrupt feature may also be used to generate up to 8 edge selectable external
interrupts.
Figure 22 shows the Multi-Input Wake-up logic.
The Multi-Input Wake-up feature utilizes the L Port. The user selects which particular L port bit (or combination of
L Port bits) will cause the device to exit the HALT or IDLE modes. The selection is done through the register
WKEN. The register WKEN is an 8-bit read/write register, which contains a control bit for every L port bit. Setting
a particular WKEN bit enables a Wake-up from the associated L port pin.
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