Datasheet
ADuC7033
Rev. B | Page 82 of 140
Bit Description
5 to 4 Format.
00 = binary (default).
01 = reserved.
10 = hours:minutes:seconds:hundredths (23 hours to 0 hours).
11 = hours:minutes:seconds:hundredths (255 hours to 0 hours).
3 to 0 Prescaler.
0000 = source clock/1 (default).
0100 = source clock/16.
1000 = source clock/256.
1111 = source clock/32,768.
TIMER2 OR WAKE-UP TIMER
Timer2 is a 32-bit wake-up timer, count-down or count-up,
with a programmable prescaler. The prescaler is clocked directly
from one of four clock sources, namely, the core clock (which is
the default selection), the low power 32.768 kHz oscillator,
external 32.768 kHz watch crystal, or the precision 32.768 kHz
oscillator. The selected clock source can be scaled by a factor of
1, 16, 256 or 32,768. The wake-up timer continues to run when
the core clock is disabled. This gives a minimum resolution of
48.83 ns when operating at CD zero, the core is operating at
20.48 MHz with a prescaler of 1.
The counter can be formatted as a plain 32-bit value or as
hours:minutes:seconds:hundredths.
Timer2 reloads the value from T2LD when Timer2 overflows.
The Timer2 interface consists of four MMRS.
T2LD and T2VAL are 32-bit registers and hold 32-bit
unsigned integers. T2VAL is read only.
T2CLRI is an 8-bit register. Writing any value to this
register clears the Timer2 interrupt.
T2CON is the configuration MMR described in Table 55.
Timer2 Load Registers
Name: T2LD
Address: 0xFFFF0340
Default Value: 0x00000000
Access: Read/write
Function: T2LD is a 32-bit register that holds the 32-bit
value that is loaded into the counter.
Timer2 Clear Register
Name: T2CLRI
Address: 0xFFFF034C
Access: Write only
Function: This 32-bit, write only MMR is written (with
any value) by user code to clear the interrupt.
Timer2 Value Register
Name: T2VAL
Address: 0xFFFF0344
Default Value: 0xFFFFFFFF
Access: Read only
Function: T2VAL is a 32-bit register that holds the
current value of Timer2.
PRESCALER
1, 16, 256, OR 32768
TIMER2 IRQ
32-BIT
UP/DOWN COUNTER
PRECISION
32.768kHz OSCILLATOR
LOW POWER
32.768kHz OSCILLATOR
CORE
CLOCK
EXTERNAL 32.768kHz
WATCH CRYSTAL
32-BIT LOAD
TIMER2
VALUE
0
6847-032
Figure 36. Timer2 Block Diagram