ATMEGA32U4-AU Atmel, ATMEGA32U4-AU Datasheet - Page 159

• Manufacturer Part Number: ATMEGA32U4-AU
• Description: MCU AVR 32K FLASH 16MHZ 44-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA32U4-AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 26
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2.5K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Processor Series: ATMEGA32x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 2.5 KB
• Interface Type: SPI/TWI/USART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 26
• Number Of Timers: 5
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12-ch x 10-bit
• Cpu Family: ATmega
• Device Core: AVR
• Device Core Size: 8b
• Frequency (max): 16MHz
• Total Internal Ram Size: 2.5KB
• # I/os (max): 26
• Number Of Timers - General Purpose: 5
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 2.7V
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 44
• Package Type: TQFP
• Controller Family/series: AVR MEGA
• No. Of I/o's: 26
• Eeprom Memory Size: 1KB
• Ram Memory Size: 2.5KB
• Cpu Speed: 16MHz
• Rohs Compliant: Yes
• For Use With: ATSTK524 - KIT STARTER ATMEGA32M1/MEGA32C1ATSTK600 - DEV KIT FOR AVR/AVR32ATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ATMEGA32U4-16AU; ATMEGA32U4-16AU

15.11 Accessing 10-Bit Registers
7766F–AVR–11/10
If 10-bit values are written to the TCNTn and OCRnA/B/C/D registers, the 10-bit registers can be
byte accessed by the AVR CPU via the 8-bit data bus using two read or write operations. The
10-bit registers have a common 2-bit Timer/Counter4 High Byte Register (TC4H) that is used for
temporary storing of the two MSBs of the 10-bit access. The same TC4H register is shared
between all 10-bit registers. Accessing the low byte triggers the 10-bit read or write operation.
When the low byte of a 10-bit register is written by the CPU, the high byte stored in the TC4H
register, and the low byte written are both copied into the 10-bit register in the same clock cycle.
When the low byte of a 10-bit register is read by the CPU, the high byte of the 10-bit register is
copied into the TC4H register in the same clock cycle as the low byte is read.
To do a 10-bit write, the high byte must be written to the TC4H register before the low byte is
written. For a 10-bit read, the low byte must be read before the high byte.
The following code examples show how to access the 10-bit timer registers assuming that no
interrupts updates the TC4H register. The same principle can be used directly for accessing the
OCRnA/B/C/C/D registers.
Note:
The assembly code example returns the TCNTn value in the r17:r16 register pair.
Assembly Code Example
C Code Example
unsigned int i;
...
/* Set TCNTn to 0x01FF */
TCnH = 0x01;
TCNTn = 0xFF;
/* Read TCNTn into i */
i = TCNTn;
i |= ((unsigned int)TCnH << 8);
...
...
; Set TCNTn to 0x01FF
ldi r17,0x01
ldi r16,0xFF
out TCnH,r17
out TCNTn,r16
; Read TCNTn into r17:r16
in r16,TCNTn
in r17,TCnH
...
1. The example code assumes that the part specific header file is included.
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”.
ATmega16/32U4
159