ATMEGA169 ATMEL [ATMEL Corporation], ATMEGA169 Datasheet - Page 93
ATMEGA169
Manufacturer Part Number
ATMEGA169
Description
8-bit Microcontroller with 16K Bytes In-System Programmable Flash
Manufacturer
ATMEL [ATMEL Corporation]
Datasheet
1.ATMEGA169.pdf
(365 pages)
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
ATMEGA169P-15AT
Manufacturer:
PANASONIC
Quantity:
301
Part Number:
ATMEGA169P-15AT
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Part Number:
ATMEGA169P-16AU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Company:
Part Number:
ATMEGA169PA-MU
Manufacturer:
ATMEL
Quantity:
31
Company:
Part Number:
ATMEGA169PAAU
Manufacturer:
INF
Quantity:
4 275
- Current page: 93 of 365
- Download datasheet (4Mb)
Timer/Counter0 and
Timer/Counter1
Prescalers
Internal Clock Source
Prescaler Reset
External Clock Source
2514P–AVR–07/06
Timer/Counter1 and Timer/Counter0 share the same prescaler module, but the
Timer/Counters can have different prescaler settings. The description below applies to
both Timer/Counter1 and Timer/Counter0.
The Timer/Counter can be clocked directly by the system clock (by setting the CSn2:0 =
1). This provides the fastest operation, with a maximum Timer/Counter clock frequency
equal to system clock frequency (f
caler can be used as a clock source. The prescaled clock has a frequency of either
f
The prescaler is free running, i.e., operates independently of the Clock Select logic of
the Timer/Counter, and it is shared by Timer/Counter1 and Timer/Counter0. Since the
prescaler is not affected by the Timer/Counter’s clock select, the state of the prescaler
will have implications for situations where a prescaled clock is used. One example of
prescaling artifacts occurs when the timer is enabled and clocked by the prescaler (6 >
CSn2:0 > 1). The number of system clock cycles from when the timer is enabled to the
first count occurs can be from 1 to N+1 system clock cycles, where N equals the pres-
caler divisor (8, 64, 256, or 1024).
It is possible to use the prescaler reset for synchronizing the Timer/Counter to program
execution. However, care must be taken if the other Timer/Counter that shares the
same prescaler also uses prescaling. A prescaler reset will affect the prescaler period
for all Timer/Counters it is connected to.
An external clock source applied to the T1/T0 pin can be used as Timer/Counter clock
(clk
chronization logic. The synchronized (sampled) signal is then passed through the edge
detector. Figure 38 shows a functional equivalent block diagram of the T1/T0 synchroni-
zation and edge detector logic. The registers are clocked at the positive edge of the
internal system clock (
system clock.
The edge detector generates one clk
ative (CSn2:0 = 6) edge it detects.
Figure 38. T1/T0 Pin Sampling
The synchronization and edge detector logic introduces a delay of 2.5 to 3.5 system
clock cycles from an edge has been applied to the T1/T0 pin to the counter is updated.
Enabling and disabling of the clock input must be done when T1/T0 has been stable for
at least one system clock cycle, otherwise it is a risk that a false Timer/Counter clock
pulse is generated.
Each half period of the external clock applied must be longer than one system clock
cycle to ensure correct sampling. The external clock must be guaranteed to have less
than half the system clock frequency (f
CLK_I/O
Tn
T1
clk
/clk
I/O
/8, f
T0
CLK_I/O
). The T1/T0 pin is sampled once every system clock cycle by the pin syn-
D
LE
/64, f
Q
CLK_I/O
Synchronization
clk
D
I/O
/256, or f
). The latch is transparent in the high period of the internal
Q
CLK_I/O
CLK_I/O
T1
/clk
ExtClk
). Alternatively, one of four taps from the pres-
T
/1024.
0
< f
pulse for each positive (CSn2:0 = 7) or neg-
clk_I/O
/2) given a 50/50% duty cycle. Since
D
Q
ATmega169/V
Edge Detector
Tn_sync
(To Clock
Select Logic)
93
Related parts for ATMEGA169
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
Part Number:
Description:
Atmel CryptoMemory
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
Atmel CryptoMemory
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
Atmel CryptoMemory, 16Kbit
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
8-bit Atmel Microcontrollers
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
8-bit Atmel Microcontroller with 64K/128K/256K Bytes In-System Programmable Flash
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
8-bit Atmel Microcontroller with 16/32/64/128K Bytes In-System Programmable Flash
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
8-bit Atmel Microcontroller with 16/32/64K Bytes In-System Programmable Programmable
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
INTERVAL AND WIPE/WASH WIPER CONTROL IC WITH DELAY
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
Low-Voltage Voice-Switched IC for Hands-Free Operation
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
MONOLITHIC INTEGRATED FEATUREPHONE CIRCUIT
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
AM-FM Receiver IC U4255BM-M
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
Monolithic Integrated Feature Phone Circuit
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
Multistandard Video-IF and Quasi Parallel Sound Processing
Manufacturer:
ATMEL Corporation
Datasheet: