ATMEGA88-20AJ Atmel, ATMEGA88-20AJ Datasheet - Page 175

IC MCU AVR 8K 5V 20MHZ 32-TQFP

ATMEGA88-20AJ

Manufacturer Part Number
ATMEGA88-20AJ
Description
IC MCU AVR 8K 5V 20MHZ 32-TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets

Specifications of ATMEGA88-20AJ

Core Processor
AVR
Core Size
8-Bit
Speed
20MHz
Connectivity
I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
23
Program Memory Size
8KB (4K 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
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
32-TQFP, 32-VQFP
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
ATMEGA88-24AJ
ATMEGA88-24AJ

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ATMEGA88-20AJ
Manufacturer:
Atmel
Quantity:
10 000
19.4.1
2545S–AVR–07/10
Parity Bit Calculation
A frame starts with the start bit followed by the least significant data bit. Then the next data bits,
up to a total of nine, are succeeding, ending with the most significant bit. If enabled, the parity bit
is inserted after the data bits, before the stop bits. When a complete frame is transmitted, it can
be directly followed by a new frame, or the communication line can be set to an idle (high) state.
Figure 19-4
optional.
Figure 19-4. Frame Formats
must be
The frame format used by the USART is set by the UCSZn2:0, UPMn1:0 and USBSn bits in
UCSRnB and UCSRnC. The Receiver and Transmitter use the same setting. Note that changing
the setting of any of these bits will corrupt all ongoing communication for both the Receiver and
Transmitter.
The USART Character SiZe (UCSZn2:0) bits select the number of data bits in the frame. The
USART Parity mode (UPMn1:0) bits enable and set the type of parity bit. The selection between
one or two stop bits is done by the USART Stop Bit Select (USBSn) bit. The Receiver ignores
the second stop bit. An FE (Frame Error) will therefore only be detected in the cases where the
first stop bit is zero.
The parity bit is calculated by doing an exclusive-or of all the data bits. If odd parity is used, the
result of the exclusive or is inverted. The relation between the parity bit and data bits is as
follows:
If used, the parity bit is located between the last data bit and first stop bit of a serial frame.
St
(n)
P
Sp
IDLE
P
P
d
even
odd
n
illustrates the possible combinations of the frame formats. Bits inside brackets are
(IDLE)
St
Start bit, always low.
Data bits (0 to 8).
Parity bit. Can be odd or even.
Stop bit, always high.
No transfers on the communication line (RxDn or TxDn). An IDLE line
high.
Parity bit using even parity
Parity bit using odd parity
Data bit n of the character
P
0
P
even
odd
1
=
=
d
d
2
n 1
n 1
3
4
FRAME
[5]
d
d
3
3
[6]
d
d
2
2
[7]
d
d
1
1
[8]
ATmega48/88/168
d
d
0
0
[P]
0
1
Sp1 [Sp2]
(St / IDLE)
175

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