ATTINY9-MAHR Atmel, ATTINY9-MAHR Datasheet - Page 72

• Manufacturer Part Number: ATTINY9-MAHR
• Description: IC MCU AVR 1K FLASH 8UDFN
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY9-MAHR

• Package / Case: 8-UDFN Exposed Pad
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Speed: 12MHz
• Number Of I /o: 4
• Core Processor: AVR
• Program Memory Type: FLASH
• Ram Size: 32 x 8
• Program Memory Size: 1KB (1K x 8)
• Oscillator Type: Internal
• Peripherals: POR, PWM, WDT
• Core Size: 8-Bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -
• Connectivity: -
• Lead Free Status / Rohs Status: Details

11.10 Accessing 16-bit Registers
72
ATtiny4/5/9/10
Figure 11-15. Timer/Counter Timing Diagram, with Prescaler (f
The TCNT0, OCR0A/B, and ICR0 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 OCR0A/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 example shows 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 OCR0A/B and ICR0 Registers.
and ICF n
(PC and PFC PWM)
TOVn
(CTC and FPWM)
(Update at TOP)
TCNTn
TCNTn
OCRnx
(clk
as TOP)
clk
clk
I/O
(FPWM)
I/O
Tn
/8)
(if used
TOP - 1
TOP - 1
Old OCRnx Value
TOP
TOP
clk_I/O
BOTTOM
TOP - 1
/8)
New OCRnx Value
BOTTOM + 1
TOP - 2
8127D–AVR–02/10