AT90CAN128-16AE ATMEL Corporation, AT90CAN128-16AE Datasheet - Page 142

• Manufacturer Part Number: AT90CAN128-16AE
• Description: 8-bit Avr Microcontroller With 128K Bytes of Isp Flash And CAN Controller.flash (Kbytes) 128 Vcc (V) 2.7-5.5 EEPROM (Kbytes) 4 SRAM (bytes) 4K CAN (mess. Obj.) 15
• Manufacturer: ATMEL Corporation

Definitions
142
AT90CAN128
Figure 60. 8-bit Timer/Counter2 Block Diagram
The Timer/Counter (TCNT2) and Output Compare Register (OCR2A) are 8-bit registers.
Interrupt request (shorten as Int.Req.) signals are all visible in the Timer Interrupt Flag
Register (TIFR2). All interrupts are individually masked with the Timer Interrupt Mask
Register (TIMSK2). TIFR2 and TIMSK2 are not shown in the figure.
The Timer/Counter can be clocked internally, via the prescaler, or asynchronously
clocked from the TOSC1/2 pins, as detailed later in this section. The asynchronous
operation is controlled by the Asynchronous Status Register (ASSR). The Clock Select
logic block controls which clock source the Timer/Counter uses to increment (or decre-
ment) its value. The Timer/Counter is inactive when no clock source is selected. The
output from the Clock Select logic is referred to as the timer clock (clk
The double buffered Output Compare Register (OCR2A) is compared with the
Timer/Counter value at all times. The result of the compare can be used by the Wave-
form Generator to generate a PWM or variable frequency output on the Output Compare
pin (OC2A). See “Output Compare Unit” on page 144 for details. The compare match
event will also set the compare flag (OCF2A) which can be used to generate an Output
Compare interrupt request.
The definitions in Table 65 are also used extensively throughout the section.
Status flags
Timer/Counter
TCNTn
OCRnx
=
ASSRn
direction
count
clear
BOTTOM
Synchronized Status flags
= 0
Control Logic
=
TCCRnx
TOP
asynchronous mode
0xFF
select (ASn)
clk
Tn
Synchronization Unit
Prescaler
OCnx
(Int.Req.)
Generation
Waveform
T2
).
Oscillator
4250C–CAN–03/04
T/C
OCnx
clk
TOVn
(Int.Req.)
clk
clk
ASY
I/O
I/O
TOSC1
TOSC2