ATMEGA16U2-16AU Atmel, ATMEGA16U2-16AU Datasheet - Page 183

• Manufacturer Part Number: ATMEGA16U2-16AU
• Description: 8-bit Microcontrollers - MCU 16K Flash
• Manufacturer: Atmel

Specifications of ATMEGA16U2-16AU

• Product Category: 8-bit Microcontrollers - MCU
• Rohs: yes
• Core: AVR
• Data Bus Width: 8 bit
• Program Memory Size: 16 KB
• Data Ram Size: 1.25 KB
• Data Rom Size: 512 B
• Program Memory Type: Flash
• Factory Pack Quantity: 1250

19.7.4
19.7.5
19.8
7799D–AVR–11/10
AVR USART MSPIM vs. AVR SPI
UCSRnC – USART MSPIM Control and Status Register n C
UBRRnL and UBRRnH – USART MSPIM Baud Rate Registers
• Bit 7:6 - UMSELn[1:0]: USART Mode Select
These bits select the mode of operation of the USART as shown in
USART Control and Status Register n C” on page 169
operation. The MSPIM is enabled when both UMSELn bits are set to one. The UDORDn,
UCPHAn, and UCPOLn can be set in the same write operation where the MSPIM is enabled.
Table 19-3.
• Bit 5:3 - Reserved Bits in MSPI mode
When in MSPI mode, these bits are reserved for future use. For compatibility with future devices,
these bits must be written to zero when UCSRnC is written.
• Bit 2 - UDORDn: Data Order
When set to one the LSB of the data word is transmitted first. When set to zero the MSB of the
data word is transmitted first. Refer to the Frame Formats section page 4 for details.
• Bit 1 - UCPHAn: Clock Phase
The UCPHAn bit setting determine if data is sampled on the leasing edge (first) or tailing (last)
edge of XCKn. Refer to the SPI Data Modes and Timing section page 4 for details.
• Bit 0 - UCPOLn: Clock Polarity
The UCPOLn bit sets the polarity of the XCKn clock. The combination of the UCPOLn and
UCPHAn bit settings determine the timing of the data transfer. Refer to the SPI Data Modes and
Timing section page 4 for details.
The function and bit description of the baud rate registers in MSPI mode is identical to normal
USART operation. See “UBRRnL and UBRRnH – USART Baud Rate Registers” on page 171.
The USART in MSPIM mode is fully compatible with the AVR SPI regarding:
Bit
Read/Write
Initial Value
• 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.
UMSELn1
0
0
1
1
UMSELn1
UMSELn Bits Settings
R/W
7
0
UMSELn0
R/W
6
0
UMSELn0
R
5
–
0
0
1
0
1
R
4
–
0
ATmega8U2/16U2/32U2
R
Mode
Asynchronous USART
(Reserved)
Master SPI (MSPIM)
3
–
0
Synchronous USART
for full description of the normal USART
UDORDn
R/W
2
1
Table
UCPHAn
R/W
1
1
19-3. See
UCPOLn
R/W
0
0
“UCSRnC –
UCSRnC
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