ATMEGA64RZAV-10PU Atmel, ATMEGA64RZAV-10PU Datasheet - Page 170

• Manufacturer Part Number: ATMEGA64RZAV-10PU
• Description: MCU ATMEGA644/AT86RF230 40-DIP
• Manufacturer: Atmel
• Series: ATMEGAr

Specifications of ATMEGA64RZAV-10PU

• Frequency: 2.4GHz
• Modulation Or Protocol: 802.15.4 Zigbee
• Power - Output: 3dBm
• Sensitivity: -101dBm
• Voltage - Supply: 1.8 V ~ 3.6 V
• Data Interface: PCB, Surface Mount
• Memory Size: 64kB Flash, 2kB EEPROM, 4kB RAM
• Antenna Connector: PCB, Surface Mount
• Package / Case: 40-DIP (0.600", 15.24mm)
• Wireless Frequency: 2.4 GHz
• Interface Type: JTAG, SPI
• Output Power: 3 dBm
• For Use With: ATSTK600-TQFP32 - STK600 SOCKET/ADAPTER 32-TQFPATAVRISP2 - PROGRAMMER AVR IN SYSTEMATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Operating Temperature: -
• Applications: -
• Data Rate - Maximum: -
• Current - Transmitting: -
• Current - Receiving: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: ATmega64

17.5
170
USART Initialization
ATmega644
The USART has to be initialized before any communication can take place. The initialization pro-
cess normally consists of setting the baud rate, setting frame format and enabling the
Transmitter or the Receiver depending on the usage. For interrupt driven USART operation, the
Global Interrupt Flag should be cleared (and interrupts globally disabled) when doing the
initialization.
Before doing a re-initialization with changed baud rate or frame format, be sure that there are no
ongoing transmissions during the period the registers are changed. The TXCn Flag can be used
to check that the Transmitter has completed all transfers, and the RXC Flag can be used to
check that there are no unread data in the receive buffer. Note that the TXCn Flag must be
cleared before each transmission (before UDRn is written) if it is used for this purpose.
The following simple USART initialization code examples show one assembly and one C func-
tion that are equal in functionality. The examples assume asynchronous operation using polling
(no interrupts enabled) and a fixed frame format. The baud rate is given as a function parameter.
For the assembly code, the baud rate parameter is assumed to be stored in the r17:r16
Registers.
Note:
More advanced initialization routines can be made that include frame format as parameters, dis-
able interrupts and so on. However, many applications use a fixed setting of the baud and
control registers, and for these types of applications the initialization code can be placed directly
in the main routine, or be combined with initialization code for other I/O modules.
Assembly Code Example
C Code Example
USART_Init:
void USART_Init( unsigned int baud )
{
}
; Set baud rate
out
out
; Enable receiver and transmitter
ldi
out
; Set frame format: 8data, 2stop bit
ldi
out
ret
/* Set baud rate */
UBRRHn = (unsigned char)(baud>>8);
UBRRLn = (unsigned char)baud;
/* Enable receiver and transmitter */
UCSRnB = (1<<RXENn)|(1<<TXENn);
/* Set frame format: 8data, 2stop bit */
UCSRnC = (1<<USBSn)|(3<<UCSZn0);
1. See “About Code Examples” on page 8.
UBRRHn, r17
UBRRLn, r16
r16, (1<<RXENn)|(1<<TXENn)
UCSRnB,r16
r16, (1<<USBSn)|(3<<UCSZn0)
UCSRnC,r16
(1)
(1)
2593N–AVR–07/10