ATmega324P Automotive Atmel Corporation, ATmega324P Automotive Datasheet - Page 174

• Manufacturer Part Number: ATmega324P Automotive
• Manufacturer: Atmel Corporation

Specifications of ATmega324P Automotive

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 32
• Ext Interrupts: 32
• Usb Speed: No
• Usb Interface: No
• Spi: 3
• Twi (i2c): 1
• Uart: 2
• 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: No
• Crypto Engine: No
• Sram (kbytes): 2
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 125
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 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

17.4.2
174
ATmega164P/324P/644P
Double Speed Operation (U2Xn)
Table 17-1 on page 174
for calculating the UBRRn value for each mode of operation using an internally generated clock
source.
Table 17-1.
Note:
Some examples of UBRRn values for some system clock frequencies are found in
page
The transfer rate can be doubled by setting the U2Xn bit in UCSRnA. Setting this bit only has
effect for the asynchronous operation. Set this bit to zero when using synchronous operation.
Setting this bit will reduce the divisor of the baud rate divider from 16 to 8, effectively doubling
the transfer rate for asynchronous communication. Note however that the Receiver will in this
case only use half the number of samples (reduced from 16 to 8) for data sampling and clock
recovery, and therefore a more accurate baud rate setting and system clock are required when
this mode is used. For the Transmitter, there are no downsides.
Operating Mode
Asynchronous Normal
mode (U2Xn = 0)
Asynchronous Double
Speed mode (U2Xn = 1)
Synchronous Master
mode
195.
BAUD
f
UBRRn
OSC
1. The baud rate is defined to be the transfer rate in bit per second (bps)
Equations for Calculating Baud Rate Register Setting
Baud rate (in bits per second, bps)
System Oscillator clock frequency
Contents of the UBRRHn and UBRRLn Registers, (0-4095)
contains equations for calculating the baud rate (in bits per second) and
Equation for Calculating Baud
BAUD
BAUD
BAUD
=
=
=
Rate
----------------------------------------- -
16 UBRRn
-------------------------------------- -
8 UBRRn
-------------------------------------- -
2 UBRRn
(1)
f
f
f
OSC
OSC
OSC
+
+
+
1
1
1
UBRRn
UBRRn
UBRRn
Equation for Calculating UBRR
=
=
=
----------------------- - 1
16BAUD
------------------- - 1
8BAUD
------------------- - 1
2BAUD
Value
f
f
f
OSC
OSC
OSC
Table 17-9 on
7674F–AVR–09/09
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–
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