ATmega8HVA Atmel Corporation, ATmega8HVA Datasheet - Page 90

• Manufacturer Part Number: ATmega8HVA
• Manufacturer: Atmel Corporation

Specifications of ATmega8HVA

• Flash (kbytes): 8 Kbytes
• Pin Count: 28
• Max. Operating Frequency: 4 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 3
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 6
• Ext Interrupts: 3
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 6
• Adc Resolution (bits): 12
• Adc Speed (ksps): 1.9
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.5
• Eeprom (bytes): 256
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -20 to 85
• I/o Supply Class: 1.8 to 9.0
• Operating Voltage (vcc): 1.8 to 9.0
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Input Capture Channels: 2
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

17.10 Register Description
17.10.1
90
ATmega8HVA/16HVA
TCCRnA – Timer/Counter n Control Register A
• Bit 7– TCWn: Timer/Counter Width
When this bit is written to one 16-bit mode is selected. The Timer/Counter width is set to 16-bits
and the Output Compare Registers OCRnA and OCRnB are combined to form one 16-bit Output
Compare Register. Because the 16-bit registers TCNTnH/L and OCRnB/A are accessed by the
AVR CPU via the 8-bit data bus, special procedures must be followed. These procedures are
described in section
• Bit 6– ICENn: Input Capture Mode Enable
The Input Capture Mode is enabled when this bit is written to one.
• Bit 5 – ICNCn: Input Capture Noise Canceler
Setting this bit activates the Input Capture Noise Canceler. When the noise canceler is acti-
vated, the input from the Input Capture Source is filtered. The filter function requires four
successive equal valued samples of the Input Capture Source for changing its output. The Input
Capture is therefore delayed by four System Clock cycles when the noise canceler is enabled.
• Bit 4 – ICESn: Input Capture Edge Select
This bit selects which edge on the Input Capture Source that is used to trigger a capture event.
When the ICESn bit is written to zero, a falling (negative) edge is used as trigger, and when the
ICESn bit is written to one, a rising (positive) edge will trigger the capture. When a capture is trig-
gered according to the ICESn setting, the counter value is copied into the Input Capture
Register. The event will also set the Input Capture Flag (ICFn), and this can be used to cause an
Input Capture Interrupt, if this interrupt is enabled.
• Bit 3 - ICSn: Input Capture Select
When written to a logic one, this bit selects the alternate Input Capture Source as trigger for the
Timer/Counter input capture function. To trigger the Timer/Counter Input Capture interrupt, the
ICIEn bit in the Timer Interrupt Mask Register (TIMSK) must be set. See
and
• Bits 2:0 – Res: Reserved Bits
These bits are reserved bits in the ATmega8HVA/16HVA and will always read as zero.
• Bit 0 – WGMn0: Waveform Generation Mode
This bit controls the counting sequence of the counter, the source for maximum (TOP) counter
value, see
Normal mode (counter) and Clear Timer on Compare Match (CTC) mode (see
Timing Diagrams” on page
Bit
Read/Write
Initial Value
Table 17-4 on page
Figure 17-6 on page
TCWn
R/W
7
0
”Accessing Registers in 16-bit Mode” on page
ICENn
84.
R/W
6
0
85).
85. Modes of operation supported by the Timer/Counter unit are:
ICNCn
R/W
5
0
ICESn
R/W
4
0
ICSn
R/W
0
3
R
2
–
0
86.
R
1
–
0
Table 17-3 on page 84
WGMn0
R/W
”Timer/Counter
0
0
8024A–AVR–04/08
TCCRnA