ATMEGA162-16PJ Atmel, ATMEGA162-16PJ Datasheet - Page 172

• Manufacturer Part Number: ATMEGA162-16PJ
• Description: IC MCU AVR 16K 5V 16MHZ 40-DIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA162-16PJ

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: EBI/EMI, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 35
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Data Converters: -

USART
Initialization
172
ATmega162/V
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 TXC 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 TXC Flag must be
cleared before each transmission (before UDR 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 Regis-
ters. When the function writes to the UCSRC Register, the URSEL bit (MSB) must be set due to
the sharing of I/O location by UBRRH and UCSRC.
Note:
Assembly Code Example
C Code Example
USART_Init:
#define FOSC 1843200// Clock Speed
#define BAUD 9600
#define MYUBRR FOSC/16/BAUD-1
void main( void )
{
}
void USART_Init( unsigned int ubrr )
{
}
; Set baud rate
out
out
; Enable receiver a?d transmitter
ldi
out
; Set frame format:?8data, 2stop bit
ldi
out
ret
...
USART_Init ( MYUBRR );
...
/* Set baud rate */
UBRRH = (unsigned c?ar)(ubrr>>8);
UBRRL = (unsigned c?ar)ubrr;
/* Enable receiver ?nd transmitter */
UCSRB = (1<<RXEN)|(1<<TX?N);
/* Set frame format? 8data, 2stop bit */
UCSRC = (1<<URSEL)|(1<<U?BS)|(3<<UCSZ0);
1. See
UBRRH, r17
UBRRL, r16
r16, (1<<RXEN)|(1<<TXEN)
UCSRB,r16
r16, (1<<URSEL)|(1<<USBS)|(3<<UCSZ0)
UCSRC,r16
“About Code Examples” on page
(1)
(1)
8.
2513K–AVR–07/09