ATAVRSB202 Atmel, ATAVRSB202 Datasheet - Page 126

• Manufacturer Part Number: ATAVRSB202
• Description: KIT BATT MGMT FOR ATMEGA32HVB
• Manufacturer: Atmel

Specifications of ATAVRSB202

• Main Purpose: *
• Embedded: *
• Utilized Ic / Part: *
• Primary Attributes: *
• Secondary Attributes: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

21.6
21.6.1
21.6.2
8042B–AVR–06/10
Register Description
BGCCR – Bandgap Calibration C Register
BGCRR – Bandgap Calibration R Register
•
These bits are reserved and will always read as zero.
•
These bits are used for trimming of the nominal value of the bandgap reference voltage. These
bits are binary coded. Minimum VREF: 000000, maximum VREF: 111111. Step size is approxi-
mately 2 mV. The application software should read the Atmel factory calibration value and store
it to the BGCCR register. See ”Reading the Signature Row from Software” on page 199 for
details.
•
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. The application software should read the Atmel factory calibration value
and store it to the BGCRR register. See ”Reading the Signature Row from Software” on page
199 for details.
Bit
(0xD0)
Read/Write
Initial Value
Bit
(0xD1)
Read/Write
Initial Value
Bits 7:6 – Reserved
Bit 5:0 – BGCC[5:0]: BG Calibration of PTAT Current
Bit 7:0 – BGCR[7:0]: BG Calibration of Resistor ladder
BGCR7
R/W
R
7
–
0
7
0
BGCR6
R/W
R
6
–
0
6
0
BGCC5
BGCR5
R/W
R/W
5
0
5
0
BGCC4
BGCR4
R/W
R/W
4
0
4
0
BGCC3
BGCR3
R/W
R/W
ATmega16HVB/32HVB
3
0
3
1
BGCC2
BGCR2
R/W
R/W
2
0
2
1
BGCC1
BGCR1
R/W
R/W
1
0
1
1
BGCC0
BGCR0
R/W
R/W
0
0
0
1
Figure 21-2
BGCCR
BGCRR
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