t6020m ATMEL Corporation, t6020m Datasheet - Page 29

• Manufacturer Part Number: t6020m
• Description: Low-current Microcontroller For Watchdog Function
• Manufacturer: ATMEL Corporation

able and disable the modulator output for a programmable
count of pulses.
For programming the time interval, the timer has a 4-bit
and an 8-bit compare register. For programming the timer
function, it has four mode and control registers. The
comparator output of stage 2 is controlled by a special
compare mode register (T2CM). This register contains
mask bits for the actions (counter reset, output toggle,
timer interrupt) which can be triggered by a compare
match event or the counter overflow. This architecture en-
ables the timer function for various modes.
T1OUT
Timer 2 Modes
Mode 1: 12-bit compare counter
The 4-bit stage and the 8-bit stage work together as a 12-bit compare counter. A compare match signal of the 4-bit and
the 8-bit stage generates the signal for the counter reset, toggle flip-flop or interrupt. The compare action is program-
mable via the compare mode register (T2CM). The 4-bit counter overflow (OVF1) supplies the clock output (POUT)
with clocks. The duty cycle generator (DCG) has to be bypassed in this mode.
Rev. A3, 02-Apr-01
T2I
SYSCL
CL2/1
SCL
T2C
4-bit compare
4-bit counter
4-bit register
CL2/1
RES
RES
4–bit Counter 2/1
CM1
Compare 2/1
T2CO1
T2D1, 0
DCG
POUT (CL2/1 /16)
P4CR
OVF1
CM1
SSI POUT
8-bit compare
8-bit counter
8-bit register
POUT
Figure 27. 12-bit compare counter
I/O–bus
Control
CL2/2
Figure 26. Timer 2
T2M1
T2CM
RES
OVF2
CM2
DCG
T2RM
Timer 2 compare data values
The Timer 2 has a 4-bit compare register (T2CO1) and an
8-bit compare register (T2CO2). Both these compare
registers are cascadable as a 12-bit compare register, or
8-bit compare register and 4-bit compare register.
For 12-bit compare data value: m = x +1 0
For 8-bit compare data value: n = y +1 0
For 4-bit compare data value: l = z +1
RES
T2OTM
8–bit Counter 2/2
Compare 2/2
T2CO2
and T2OTM–bit
output mode
DCGO
Timer 2
I/O–bus
OVF2
TOG2
INT4
SSI
T2IM
SO
MOUT
T6020M
Manchester–
T2CTM
modulator
OUTPUT
Biphase–,
T2M2
SSI
0
Control
M2
x
y
z
Modulator 3
output–stage
29 (54)
modulator
TOG2
INT4
Timer 2
13778
15
4095
255
to
13394
T2O