A000003 Arduino, A000003 Datasheet - Page 204

MCU, MPU & DSP Development Tools MINI

A000003

Manufacturer Part Number
A000003
Description
MCU, MPU & DSP Development Tools MINI
Manufacturer
Arduino
Series
-r
Type
MCUr
Datasheets

Specifications of A000003

Processor To Be Evaluated
Atmega328
Processor Series
ATmega
Data Bus Width
8 bit
Interface Type
USB, RS-232
Operating Supply Voltage
7 V to 9 V
Contents
Board
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
For Use With/related Products
ATmega168
20.7
204
AVR USART MSPIM vs. AVR SPI
ATmega48/88/168
The USART in MSPIM mode is fully compatible with the AVR SPI regarding:
• Master mode timing diagram.
• The UCPOLn bit functionality is identical to the SPI CPOL bit.
• The UCPHAn bit functionality is identical to the SPI CPHA bit.
• The UDORDn bit functionality is identical to the SPI DORD bit.
However, since the USART in MSPIM mode reuses the USART resources, the use of the
USART in MSPIM mode is somewhat different compared to the SPI. In addition to differences of
the control register bits, and that only master operation is supported by the USART in MSPIM
mode, the following features differ between the two modules:
• The USART in MSPIM mode includes (double) buffering of the transmitter. The SPI has no
• The USART in MSPIM mode receiver includes an additional buffer level.
• The SPI WCOL (Write Collision) bit is not included in USART in MSPIM mode.
• The SPI double speed mode (SPI2X) bit is not included. However, the same effect is achieved
• Interrupt timing is not compatible.
• Pin control differs due to the master only operation of the USART in MSPIM mode.
A comparison of the USART in MSPIM mode and the SPI pins is shown in
204.
Table 20-3.
buffer.
by setting UBRRn accordingly.
USART_MSPIM
XCKn
RxDn
TxDn
(N/A)
Comparison of USART in MSPIM mode and SPI pins.
MOSI
MISO
SCK
SPI
SS
MSPIM
Comment
Master Out only
Master In only
(Functionally identical)
Not supported by USART in
Table 20-3 on page
2545S–AVR–07/10

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