Rainbow Electronics AT90LS8535 - Manual (Page 42)

42
AT90S/LS8535
1041H–11/01
Note: X = A
In PWM mode, the Timer Overflow Flag1 (TOV1) is set when the counter advances from
$0000. Timer Overflow Interrupt1 operates exactly as in normal Timer/Counter mode,
i.e., it is executed when TOV1 is set, provided that Timer Overflow Interrupt1 and global
interrupts are enabled. This also applies to the Timer Output Compare1 flags and
interrupts.
8-bit Timer/Counter2 Figure 34 shows the block diagram for Timer/Counter2.
Figure 34. Timer/Counter2 Block Diagram
The 8-bit Timer/Counter2 can select clock source from PCK2 or prescaled PCK2. It can
also be stopped as described in the specification for the Timer/Counter Control Register
(TCCR2).
The diffe rent statu s flag s (Overflow an d Com pare M atch) a re foun d in th e
Timer/Counter Interrupt Flag Register (TIFR). Control signals are found in the
1 0 TOP H
1 1 $0000 H
1 1 TOP L
Table 16. PWM Outputs OCR1X = $0000 or TOP
COM1X1 COM1X0 OCR1X Output OC1X
8-BIT DATA BUS
8-BIT ASYNCH T/C2 DATA BUS
ASYNCH. STATUS
REGISTER (ASSR)
TIMER INT. FLAG
REGISTER (TIFR)
TIMER/COUNTER2
(TCNT2)
SYNCH UNIT
8-BIT COMPARATOR
OUTPUT COMPARE
REGISTER2 (OCR2)
TIMER INT. MASK
REGISTER (TIMSK)
0
0
0
7
7
7
T/C CLK SOURCE
UP/DOWN
T/C CLEAR
CONTROL
LOGIC
TOV0 TOV1
OCF1B OCF1A
ICF1 TOV2 OCF2
OCF2 TOV2 TOIE0 TOIE1 OCIE1A OCIE1B TICIE1 TOIE2 OCIE2
OCR2UB
TC2UB ICR2UB
TOSC1
CK
PCK2
T/C2 OVER-
FLOW IRQ
T/C2 COMPARE
MATCH IRQ
T/C2 CONTROL
REGISTER (TCCR2)
CS22
COM21 PWM2
AS2
CS21
COM20
CS20 CTC2
CK