atmega32u4-16mu ATMEL Corporation, atmega32u4-16mu Datasheet - Page 235
![no-image](/images/manufacturer_photos/0/0/79/atmel_corporation_sml.jpg)
atmega32u4-16mu
Manufacturer Part Number
atmega32u4-16mu
Description
Atmega32u4 8-bit Avr Microcontroller With 32k Bytes Of Isp Flash And Usb Controller
Manufacturer
ATMEL Corporation
Datasheet
1.ATMEGA32U4-16MU.pdf
(431 pages)
- Current page: 235 of 431
- Download datasheet (6Mb)
20.4.1
7766A–AVR–03/08
USART MSPIM Initialization
The UDORDn bit in UCSRnC sets the frame format used by the USART in MSPIM mode. 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.
16-bit data transfer can be achieved by writing two data bytes to UDRn. A UART transmit com-
plete interrupt will then signal that the 16-bit value has been shifted out.
The USART in MSPIM mode has to be initialized before any communication can take place. The
initialization process normally consists of setting the baud rate, setting master mode of operation
(by setting DDR_XCKn to one), setting frame format and enabling the Transmitter and the
Receiver. Only the transmitter can operate independently. For interrupt driven USART opera-
tion, the Global Interrupt Flag should be cleared (and thus interrupts globally disabled) when
doing the initialization.
Note:
Before doing a re-initialization with changed baud rate, data mode, or frame format, be sure that
there is 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 RXCn 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 polling (no interrupts enabled). 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.
To ensure immediate initialization of the XCKn output the baud-rate register (UBRRn) must be
zero at the time the transmitter is enabled. Contrary to the normal mode USART operation the
UBRRn must then be written to the desired value after the transmitter is enabled, but before the
first transmission is started. Setting UBRRn to zero before enabling the transmitter is not neces-
sary if the initialization is done immediately after a reset since UBRRn is reset to zero.
ATmega32U4
235
Related parts for atmega32u4-16mu
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
![ATmega32](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
Atmel Corporation
Datasheet:
![ATMEGA32-8AU](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
ATMEL Corporation
Datasheet:
![ATMEGA128RFA1-ZU](/photos/12/13/121326/313-64-qfn_tmb.jpg)
Part Number:
Description:
IC AVR MCU 2.4GHZ XCEIVER 64QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA328P-20PU](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
Manufacturer:
Atmel
Datasheet:
![ATMEGA64RZAV-10PU](/photos/14/18/141872/atmega64rzav-10pu_tmb.jpg)
Part Number:
Description:
MCU ATMEGA644/AT86RF230 40-DIP
Manufacturer:
Atmel
Datasheet:
![ATMEGA64RZAPV-10MU](/photos/12/13/121326/313-64-qfn_tmb.jpg)
Part Number:
Description:
BUNDLE ATMEGA644P/AT86RF230 QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA64RZAPV-10AU](/photos/6/70/67042/313-44-tqfp_tmb.jpg)
Part Number:
Description:
BUNDLE ATMEGA644P/AT86RF230 TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA128RZAV-8AU](/photos/12/13/121332/313-64-tqfp_tmb.jpg)
Part Number:
Description:
MCU ATMEGA1281/AT86RF230 64-TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA128RZBV-8AU](/photos/6/70/67048/313-100-tqfp_tmb.jpg)
Part Number:
Description:
MCU ATMEGA1280/AT86RF230 100TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA128RZBV-8CU](/photos/6/70/67048/313-100-tqfp_tmb.jpg)
Part Number:
Description:
BUNDLE ATMEGA1280/AT86RF100-TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA256RZBV-8CU](/photos/6/89/68968/313-100-cbga_tmb.jpg)
Part Number:
Description:
BUNDLE ATMEGA2560V/AT86RF230-ZU
Manufacturer:
Atmel
Datasheet:
![ATMEGA256RZAV-8AU](/photos/12/13/121332/313-64-tqfp_tmb.jpg)
Part Number:
Description:
MCU ATMEGA2561/AT86RF230 64-TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA168PA-PU](/photos/19/6/190669/ge28pdip05-40_tmb.jpg)
Part Number:
Description:
MCU, 8BIT, AVR, 16K FLASH, 28PDIP
Manufacturer:
Atmel
Datasheet:
![MIKROE-459](/photos/40/80/408077/mcu_card_atmega_tmb.jpg)
Part Number:
Description:
Microcontroller Modules MCU CARD BIGAVR6 100P W/ ATMEGA2560
Manufacturer:
mikroElektronika