ATA6613-EK Atmel, ATA6613-EK Datasheet - Page 139

• Manufacturer Part Number: ATA6613-EK
• Description: BOARD DEMO LIN-MCM FOR ATA6613
• Manufacturer: Atmel

Specifications of ATA6613-EK

• Main Purpose: Interface, LIN + MCU
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: ATA6613
• Primary Attributes: LIN-SBC (System-Basis-Chip) Transceiver, LIN 2.0, Voltage Regulator, Window Watchdog
• Secondary Attributes: 16 kB Flash, 4 Power Modes: Pre-Normal, Normal, Sleep, Silent, 48-QFN
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

6.14.3
6.14.4
9111H–AUTO–01/11
Timer/Counter Clock Sources
Counter Unit
The Timer/Counter can be clocked by an internal or an external clock source. The clock
source is selected by the Clock Select logic which is controlled by the Clock Select (CS12:0)
bits located in the Timer/Counter control Register B (TCCR1B). For details on clock sources
and prescaler (see
The main part of the 16-bit Timer/Counter is the programmable 16-bit bi-directional counter
unit.
Figure 6-41. Counter Unit Block Diagram
Signal description (internal signals):
The 16-bit counter is mapped into two 8-bit I/O memory locations: Counter High (TCNT1H)
containing the upper eight bits of the counter, and Counter Low (TCNT1L) containing the lower
eight bits. The TCNT1H Register can only be indirectly accessed by the CPU. When the CPU
does an access to the TCNT1H I/O location, the CPU accesses the high byte temporary regis-
ter (TEMP). The temporary register is updated with the TCNT1H value when the TCNT1L is
read, and TCNT1H is updated with the temporary register value when TCNT1L is written. This
allows the CPU to read or write the entire 16-bit counter value within one clock cycle via the
8-bit data bus. It is important to notice that there are special cases of writing to the TCNT1
Register when the counter is counting that will give unpredictable results. The special cases
are described in the sections where they are of importance.
Depending on the mode of operation used, the counter is cleared, incremented, or decre-
mented at each timer clock (clk
clock source, selected by the Clock Select bits (CS12:0). When no clock source is selected
(CS12:0 = 0) the timer is stopped. However, the TCNT1 value can be accessed by the CPU,
independent of whether clk
counter clear or count operations.
Figure 6-41
Count
Direction
Clear
clk
TOP
BOTTOM
T
TCNTnH (8-bit)
1
TEMP (8-bit)
TCNTn (16-bit Counter)
DATA BUS (8-bit)
shows a block diagram of the counter and its surroundings.
“Timer/Counter0 and Timer/Counter1 Prescalers” on page
Increment or decrement TCNT1 by 1.
Select between increment and decrement.
Clear TCNT1 (set all bits to zero).
Timer/Counter clock.
Signalize that TCNT1 has reached maximum value.
Signalize that TCNT1 has reached minimum value (zero).
TCNTnL (8-bit)
T
1
is present or not. A CPU write overrides (has priority over) all
T
1
). The clk
Direction
Count
Clear
T
1
Atmel ATA6612/ATA6613
Control Logic
can be generated from an external or internal
TOP
BOTTOM
TOVn
(Int.Req.)
clk
Tn
Clock Select
Detector
(From Prescaler)
Edge
131).
Tn
139