ATTINY85-20SU Atmel, ATTINY85-20SU Datasheet - Page 68
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ATTINY85-20SU
Manufacturer Part Number
ATTINY85-20SU
Description
IC AVR MCU 8K 20MHZ 8SOIC
Manufacturer
Atmel
Series
AVR® ATtinyr
Specifications of ATTINY85-20SU
Core Processor
AVR
Core Size
8-Bit
Speed
20MHz
Connectivity
USI
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
6
Program Memory Size
8KB (4K x 16)
Program Memory Type
FLASH
Eeprom Size
512 x 8
Ram Size
512 x 8
Voltage - Supply (vcc/vdd)
2.7 V ~ 5.5 V
Data Converters
A/D 4x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
8-SOIC (5.3mm Width), 8-SOP, 8-SOEIAJ
Processor Series
ATTINY8x
Core
AVR8
Data Bus Width
8 bit
Data Ram Size
512 B
Interface Type
USI
Maximum Clock Frequency
20 MHz
Number Of Programmable I/os
6
Number Of Timers
2
Operating Supply Voltage
2.7 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
On-chip Adc
4-ch x 10-bit
For Use With
ATSTK600-DIP40 - STK600 SOCKET/ADAPTER 40-PDIPATAVRBC100 - REF DESIGN KIT BATTERY CHARGER770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAG770-1004 - ISP 4PORT FOR ATMEL AVR MCU SPIATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATAVRISP2 - PROGRAMMER AVR IN SYSTEM
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ATTINY85-20SU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
11.2.1
11.2.2
11.3
11.3.1
11.3.2
68
Timer/Counter0 Prescaler and Clock Sources
ATtiny25/45/85
Registers
Definitions
Internal Clock Source with Prescaler
Prescaler Reset
The Timer/Counter (TCNT0) and Output Compare Registers (OCR0A and OCR0B) are 8-bit
registers. Interrupt request (abbreviated to Int.Req. in the figure) signals are all visible in the
Timer Interrupt Flag Register (TIFR). All interrupts are individually masked with the Timer Inter-
rupt Mask Register (TIMSK). TIFR and TIMSK are not shown in the figure.
The Timer/Counter can be clocked internally, via the prescaler, or by an external clock source on
the T0 pin. The Clock Select logic block controls which clock source and edge the Timer/Counter
uses to increment (or decrement) its value. The Timer/Counter is inactive when no clock source
is selected. The output from the Clock Select logic is referred to as the timer clock (clk
The double buffered Output Compare Registers (OCR0A and OCR0B) is compared with the
Timer/Counter value at all times. The result of the compare can be used by the Waveform Gen-
erator to generate a PWM or variable frequency output on the Output Compare pins (OC0A and
OC0B).
set the Compare Flag (OCF0A or OCF0B) which can be used to generate an Output Compare
interrupt request.
Many register and bit references in this section are written in general form. A lower case “n”
replaces the Timer/Counter number, in this case 0. A lower case “x” replaces the Output Com-
pare Unit, in this case Compare Unit A or Compare Unit B. However, when using the register or
bit defines in a program, the precise form must be used, i.e., TCNT0 for accessing
Timer/Counter0 counter value and so on.
The definitions in
Table 11-1.
The Timer/Counter can be clocked by an internal or an external clock source. The clock source
is selected by the Clock Select logic which is controlled by the Clock Select (c) bits located in the
Timer/Counter0 Control Register (TCCR0B).
Timer/Counter0 can be clocked directly by the system clock (by setting the CS0[2:0] = 1). This
provides the fastest operation, with a maximum timer/counter clock frequency equal to system
clock frequency (f
clock source. The prescaled clock has a frequency of either f
f
The prescaler is free running, i.e. it operates independently of the Clock Select logic of
Timer/Counter0. Since the prescaler is not affected by the timer/counter’s clock select, the state
CLK_I/O
Constant
BOTTOM
MAX
TOP
/1024.
See “Output Compare Unit” on page 71.
Definitions
Description
The counter reaches BOTTOM when it becomes 0x00
The counter reaches its MAXimum when it becomes 0xFF (decimal 255)
The counter reaches the TOP when it becomes equal to the highest value in the count
sequence. The TOP value can be assigned to be the fixed value 0xFF (MAX) or the
value stored in the OCR0A Register. The assignment depends on the mode of operation
Table 11-1
CLK_I/O
). Alternatively, one of four taps from the prescaler can be used as a
are also used extensively throughout the document.
for details. The Compare Match event will also
CLK_I/O
/8, f
CLK_I/O
/64, f
2586M–AVR–07/10
CLK_I/O
T0
).
/256, or