Datasheet

ADuC7128/ADuC7129
Rev. 0 | Page 75 of 92
TIMER1—GENERAL-PURPOSE TIMER
TIMER1IRQ
CAPTURE
IRQ[31:0]
32-BIT LOAD
32-BIT
UP/DOWN COUNTER
TIMER1 VALUE
PRESCALER
1, 16, 256,
OR 32768
32.768kHz
OSCILLATOR
CORE CLOCK
FREQUENCY
GPIO
GPIO
06020-051
Figure 56. Timer1 Block Diagram
Timer1 is a 32-bit general-purpose count down or count up timer
with a programmable prescaler. The prescaler source can be
from the 32 kHz oscillator, the core clock, or one of two external
GPIOs. This source can be scaled by a factor of 1, 16, 256, or
32,768. This gives a minimum resolution of 42 ns when operating
at CD zero, the core is operating at 41.78 MHz, and with a
prescaler of 1 (ignoring external GPIO).
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. Once triggered, the
current timer value is copied to T1CAP, and the timer keeps
running. This feature can be used to determine the assertion of
an event with increased accuracy.
The Timer1 interface consists of five MMRs, as shown in
Tabl e 110.
Table 110. Timer1 Interface MMRs
Name Description
T1LD
A 32-bit register. Holds 32-bit unsigned integers.
This register is read only.
T1VAL A 32-bit register. Holds 32-bit unsigned integers.
T1CAP
A 32-bit register. Holds 32-bit unsigned integers.
This register is read only.
T1ICLR
An 8-bit register. Writing any value to this register
clears the Timer1 interrupt.
T1CON The configuration MMR (see Table 111).
Note that if the part is in a low power mode, and Timer1 is
clocked from the GPIO or low power oscillator source, then
Timer1 continues to operate.
Timer1 reloads the value from T1LD either when Timer1
overflows or immediately after T1ICLR is written.
Timer1 Load Register
Name Address Default Value Access
T1LD 0xFFFF0320 0x00000 R/W
T1LD is a 32-bit register that holds the 32-bit value that is loaded
into the counter.
Timer1 Clear Register
Name Address Default Value Access
T1ICLR 0xFFFF032C 0x00 W
This 8-bit, write-only MMR is written (with any value) by user
code to refresh (reload) Timer1.
Timer1 Value Register
Name Address Default Value Access
T1VAL 0xFFFF0324 0x0000 R
T1VAL is a 32-bit register that holds the current value of Timer1.
Timer1 Capture Register
Name Address Default Value Access
T1CAP 0xFFFF0330 0x00 R
This is a 32-bit register that holds the 32-bit value captured by
an enabled IRQ event.
Timer1 Control Register
Name Address Default Value Access
T1CON 0xFFFF0328 0x0000 R/W
This 32-bit MMR configures the mode of operation of Timer1.