ATTINY44A-SSN Atmel, ATTINY44A-SSN Datasheet - Page 103

• Manufacturer Part Number: ATTINY44A-SSN
• Description: IC MCU AVR 4KB FLASH 20MHZ 14SOI
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY44A-SSN

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 12
• Program Memory Size: 4KB (2K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Processor Series: ATTINY4x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: SPI
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 12
• Operating Supply Voltage: 1.8 V to 5.5 V
• 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
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

12.10 Accessing 16-bit Registers
8183C–AVR–03/11
Figure 12-13. Timer/Counter Timing Diagram, with Prescaler (f
The TCNT1, OCR1A/B, and ICR1 are 16-bit registers that can be accessed by the AVR CPU via
the 8-bit data bus. The 16-bit register must be byte accessed using two read or write operations.
Each 16-bit timer has a single 8-bit register for temporary storing of the high byte of the 16-bit
access. The same temporary register is shared between all 16-bit registers within each 16-bit
timer. Accessing the low byte triggers the 16-bit read or write operation. When the low byte of a
16-bit register is written by the CPU, the high byte stored in the temporary register, and the low
byte written are both copied into the 16-bit register in the same clock cycle. When the low byte of
a 16-bit register is read by the CPU, the high byte of the 16-bit register is copied into the tempo-
rary register in the same clock cycle as the low byte is read.
Not all 16-bit accesses uses the temporary register for the high byte. Reading the OCR1A/B 16-
bit registers does not involve using the temporary register.
To do a 16-bit write, the high byte must be written before the low byte. For a 16-bit read, the low
byte must be read before the high byte.
The following code examples show how to access the 16-bit timer registers assuming that no
interrupts updates the temporary register. The same principle can be used directly for accessing
the OCR1A/B and ICR1 Registers. Note that when using “C”, the compiler handles the 16-bit
access.
and ICF n
(PC and PFC PWM)
TOVn
(CTC and FPWM)
(Update at TOP)
TCNTn
TCNTn
OCRnx
as TOP)
(clk
clk
clk
I/O
(FPWM)
I/O
Tn
/8)
(if used
TOP - 1
TOP - 1
Old OCRnx Value
TOP
TOP
ATtiny24A/44A/84A
BOTTOM
TOP - 1
clk_I/O
New OCRnx Value
/8)
BOTTOM + 1
TOP - 2
103