ATmega168P Atmel Corporation, ATmega168P Datasheet - Page 189

no-image

ATmega168P

Manufacturer Part Number
ATmega168P
Description
Manufacturer
Atmel Corporation
Datasheets

Specifications of ATmega168P

Flash (kbytes)
16 Kbytes
Pin Count
32
Max. Operating Frequency
20 MHz
Cpu
8-bit AVR
# Of Touch Channels
16
Hardware Qtouch Acquisition
No
Max I/o Pins
23
Ext Interrupts
24
Usb Speed
No
Usb Interface
No
Spi
2
Twi (i2c)
1
Uart
1
Graphic Lcd
No
Video Decoder
No
Camera Interface
No
Adc Channels
8
Adc Resolution (bits)
10
Adc Speed (ksps)
15
Analog Comparators
1
Resistive Touch Screen
No
Temp. Sensor
Yes
Crypto Engine
No
Sram (kbytes)
1
Eeprom (bytes)
512
Self Program Memory
YES
Dram Memory
No
Nand Interface
No
Picopower
Yes
Temp. Range (deg C)
-40 to 85
I/o Supply Class
1.8 to 5.5
Operating Voltage (vcc)
1.8 to 5.5
Fpu
No
Mpu / Mmu
no / no
Timers
3
Output Compare Channels
6
Input Capture Channels
1
Pwm Channels
6
32khz Rtc
Yes
Calibrated Rc Oscillator
Yes

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
ATmega168P-20AU
Manufacturer:
ATMEL
Quantity:
1 250
Price:
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
ATmega168P-20MU
Manufacturer:
ATMEL
Quantity:
12 000
Price:
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
ATmega168PA-15AZ
Manufacturer:
VAC
Quantity:
120
Price:
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
ATmega168PA-15MZ
Manufacturer:
TOSHIBA
Quantity:
1 000
Price:
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
ATmega168PA-AU
Manufacturer:
Atmel
Quantity:
2 902
Price:
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
ATmega168PA-MU
Manufacturer:
ATMEL
Quantity:
4 000
Price:
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
ATmega168PA-MU
Manufacturer:
AT
Quantity:
3
Price:
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
ATmega168PA-PU
Manufacturer:
TI
Quantity:
1 240
Price:
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
ATmega168PB-AU
Manufacturer:
ATMEL
Quantity:
1 000
Price:
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
ATmega168PV-10AU
Manufacturer:
ATMEL
Quantity:
5 118
Price:
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
ATmega168PV-10MU
Manufacturer:
ATMEL
Quantity:
63
Price:
20.8.2
8025M–AVR–6/11
Asynchronous Data Recovery
Figure 20-5. Start Bit Sampling
When the clock recovery logic detects a high (idle) to low (start) transition on the RxDn line, the
start bit detection sequence is initiated. Let sample 1 denote the first zero-sample as shown in
the figure. The clock recovery logic then uses samples 8, 9, and 10 for Normal mode, and sam-
ples 4, 5, and 6 for Double Speed mode (indicated with sample numbers inside boxes on the
figure), to decide if a valid start bit is received. If two or more of these three samples have logical
high levels (the majority wins), the start bit is rejected as a noise spike and the Receiver starts
looking for the next high to low-transition. If however, a valid start bit is detected, the clock recov-
ery logic is synchronized and the data recovery can begin. The synchronization process is
repeated for each start bit.
When the receiver clock is synchronized to the start bit, the data recovery can begin. The data
recovery unit uses a state machine that has 16 states for each bit in Normal mode and eight
states for each bit in Double Speed mode.
the parity bit. Each of the samples is given a number that is equal to the state of the recovery
unit.
Figure 20-6. Sampling of Data and Parity Bit
The decision of the logic level of the received bit is taken by doing a majority voting of the logic
value to the three samples in the center of the received bit. The center samples are emphasized
on the figure by having the sample number inside boxes. The majority voting process is done as
follows: If two or all three samples have high levels, the received bit is registered to be a logic 1.
If two or all three samples have low levels, the received bit is registered to be a logic 0. This
majority voting process acts as a low pass filter for the incoming signal on the RxDn pin. The
recovery process is then repeated until a complete frame is received. Including the first stop bit.
Note that the Receiver only uses the first stop bit of a frame.
Figure 20-7 on page 190
of the start bit of the next frame.
(U2X = 0)
(U2X = 1)
(U2X = 0)
(U2X = 1)
Sample
Sample
Sample
Sample
RxD
RxD
0
0
IDLE
0
1
1
1
1
shows the sampling of the stop bit and the earliest possible beginning
2
2
3
2
3
2
4
4
5
3
5
3
6
6
Figure 20-6
7
4
7
4
8
8
START
BIT n
9
5
9
5
ATmega48P/88P/168P
10
10
shows the sampling of the data bits and
11
11
6
6
12
12
13
13
7
7
14
14
15
15
8
8
16
16
1
1
1
1
2
BIT 0
3
2
189

Related parts for ATmega168P