Datasheet

ADuC7019/20/21/22/24/25/26/27/28/29 Data Sheet
Rev. F | Page 86 of 104
Timer1 (General-Purpose Timer)
Timer1 is a general-purpose, 32-bit timer (count down or count
up) with a programmable prescaler. The source can be the
32 kHz external crystal, the core clock frequency, or an external
GPIO (P1.0 or P0.6). The maximum frequency of the clock
input is 44 Mhz). This source can be scaled by a factor of 1, 16,
256, or 32,768.
The counter can be formatted as a standard 32-bit value or as
hours: minutes: seconds: hundredths.
Timer1 has a capture register (T1CAP) that can be triggered by
a selected IRQ source initial assertion. This feature can be used
to determine the assertion of an event more accurately than the
precision allowed by the RTOS timer when the IRQ is serviced.
Timer1 can be used to start ADC conversions as shown in the
block diagram in Figure 78.
04955-035
32kHz OSCILLATOR
HCLK
P0.6
P1.0
IRQ[31:0]
PRESCALER
/1, 16, 256
OR 32,768
32-BIT
UP/DOWN
COUNTER
32-BIT
LOAD
TIMER1
VALUE
CAPTURE
TIMER1 IRQ
ADC CONVERSION
Figure 78. Timer1 Block Diagram
The Timer1 interface consists of five MMRs: T1LD, T1VAL,
T1CON, T1CLRI, and T1CAP.
Table 177. T1LD Register
Name Address Default Value Access
T1LD 0xFFFF0320 0x00000000 R/W
T1LD is a 32-bit load register.
Table 178. T1VAL Register
Name Address Default Value Access
T1VAL 0xFFFF0324 0xFFFFFFFF R
T1VAL is a 32-bit read-only register that represents the current
state of the counter.
Table 179. T1CON Register
Name Address Default Value Access
T1CON 0xFFFF0328 0x0000 R/W
T1CON is the configuration MMR described in Table 180.