ATMEGA16M1-AU Atmel, ATMEGA16M1-AU Datasheet - Page 232

• Manufacturer Part Number: ATMEGA16M1-AU
• Description: IC MCU AVR 16K FLASH 32TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA16M1-AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: CAN, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 11x10b; D/A 1x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-TQFP, 32-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Number Of I /o: -

21.6.3
21.6.4
232
ATmega16M1/32M1/64M1
Offset Compensation Schemes
ADC Accuracy Definitions
The gain stage has a built-in offset cancellation circuitry that nulls the offset of differential mea-
surements as much as possible. The remaining offset in the analog path can be measured
directly by shortening both differential inputs using the AMPxIS bit with both inputs unconnected
(see
1 Control and Status register” on page
register” on page
ment results. Using this kind of software based offset correction, offset on any channel can be
reduced below one LSB.
An n-bit single-ended ADC converts a voltage linearly between GND and V
(LSBs). The lowest code is read as 0, and the highest code is read as 2
Several parameters describe the deviation from the ideal behavior:
Figure 21-10. Offset Error
• Offset: The deviation of the first transition (0x000 to 0x001) compared to the ideal transition
• Gain Error: After adjusting for offset, the Gain Error is found as the deviation of the last
(at 0.5 LSB). Ideal value: 0 LSB
transition (0x3FE to 0x3FF) compared to the ideal transition (at 1.5 LSB below maximum).
Ideal value: 0 LSB
“AMP0CSR – Amplifier 0 Control and Status register” on page
Output Code
248). This offset residue can be then subtracted in software from the measure-
Offset
Error
248, and
“AMP1CSR – Amplifier 1 Control and Status
V
REF
Input Voltage
247,
n
-1.
“AMP1CSR – Amplifier
Ideal ADC
Actual ADC
REF
8209D–AVR–11/10
in 2
n
steps