ATMEGA48A-MMHR Atmel, ATMEGA48A-MMHR Datasheet - Page 188

IC MCU AVR 4K FLASH 28QFN

ATMEGA48A-MMHR

Manufacturer Part Number
ATMEGA48A-MMHR
Description
IC MCU AVR 4K FLASH 28QFN
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheet

Specifications of ATMEGA48A-MMHR

Package / Case
28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
Voltage - Supply (vcc/vdd)
1.8 V ~ 5.5 V
Operating Temperature
-40°C ~ 85°C
Speed
20MHz
Number Of I /o
23
Eeprom Size
256 x 8
Core Processor
AVR
Program Memory Type
FLASH
Ram Size
512 x 8
Program Memory Size
4KB (4K x 8)
Data Converters
A/D 8x10b
Oscillator Type
Internal
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Connectivity
I²C, SPI, UART/USART
Core Size
8-Bit
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
19.7.2
8271C–AVR–08/10
Receiving Frames with 9 Data Bits
Note:
The function simply waits for data to be present in the receive buffer by checking the RXCn Flag,
before reading the buffer and returning the value.
If 9-bit characters are used (UCSZn=7) the ninth bit must be read from the RXB8n bit in
UCSRnB before reading the low bits from the UDRn. This rule applies to the FEn, DORn and
UPEn Status Flags as well. Read status from UCSRnA, then data from UDRn. Reading the
UDRn I/O location will change the state of the receive buffer FIFO and consequently the TXB8n,
FEn, DORn and UPEn bits, which all are stored in the FIFO, will change.
The following code example shows a simple USART receive function that handles both nine bit
characters and the status bits.
ATmega48A/48PA/88A/88PA/168A/168PA/328/328
Assembly Code Example
C Code Example
USART_Receive:
unsigned char USART_Receive( void )
{
}
; Wait for data to be received
in r16, UCSRnA
sbrs r16, UDREn
rjmp USART_Receive
; Get and return received data from buffer
in
ret
/* Wait for data to be received */
while ( !(UCSRnA & (1<<RXCn)) )
/* Get and return received data from buffer */
return UDRn;
1.
See ”About Code Examples” on page 7.
For I/O Registers located in extended I/O map, “IN”, “OUT”, “SBIS”, “SBIC”, “CBI”, and “SBI”
instructions must be replaced with instructions that allow access to extended I/O. Typically
“LDS” and “STS” combined with “SBRS”, “SBRC”, “SBR”, and “CBR”.
r16, UDRn
;
(1)
(1)
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