ATMEGA16HVA-4CKU Atmel, ATMEGA16HVA-4CKU Datasheet - Page 119

• Manufacturer Part Number: ATMEGA16HVA-4CKU
• Description: MCU AVR 16K FLASH 4MHZ 36-LGA
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA16HVA-4CKU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 4MHz
• Connectivity: SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 7
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 9 V
• Data Converters: A/D 5x12b
• Oscillator Type: External
• Operating Temperature: -20°C ~ 85°C
• Package / Case: 36-LGA
• Processor Series: ATMEGA16x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 512 B
• Interface Type: SPI
• Maximum Clock Frequency: 4 MHz
• Number Of Programmable I/os: 6
• Number Of Timers: 2
• 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, ATAVRSB200, ATAVRSB201
• Minimum Operating Temperature: - 20 C
• On-chip Adc: 12 bit, 5 Channel
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32ATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

21.3.2
8024A–AVR–04/08
BGCRR – Bandgap Calibration R Register
• Bit 7:0 – BGCR7:0: BG Calibration of Resistor ladder
These bits are used for temperature gradient adjustment of the bandgap reference.
illustrates VREF as a function of temperature. VREF has a positive temperature coefficient at
low temperatures and negative temperature coefficient at high temperatures. Depending on the
process variations, the top of the VREF curve may be located at higher or lower temperatures.
To minimize the temperature drift in the temperature range of interest, BGCRR is used to adjust
the top of the curve towards the centre of the temperature range of interest. The BGCRR bits are
thermometer coded, resulting in 9 possible settings: 00000000, 00000001, 00000011,
00000111, … , 11111111. The value 00000000 shifts the top of the VREF curve to the highest
possible temperature, and the value 11111111 shifts the top of the VREF curve to the lowest
possible temperature.
Figure 21-2. Illustration of VREF as a function of temperature.
Bit
(0xD1)
Read/Write
Initial Value
1.5
0.5
1
0
-40
BGCR7
R/W
-20
7
0
BGCR6
R/W
6
0
0
BGCR5
R/W
5
0
Temperature range of interest
20
Temperature [
BGCR4
R/W
4
0
o
C]
40
BGCRR is used to move the top of the VREF
curve to the center of the tempearture range of
interest.
BGCR3
R/W
3
1
ATmega8HVA/16HVA
BGCR2
60
R/W
1
2
BGCR1
R/W
1
1
80
BGCR0
R/W
0
1
100
Figure 21-2
BGCRR
119