AT90PWM1-16MU Atmel, AT90PWM1-16MU Datasheet - Page 190

• Manufacturer Part Number: AT90PWM1-16MU
• Description: IC AVR PWM 8KB FLASH 16MHZ 32QFN
• Manufacturer: Atmel
• Series: AVR® 90PWM Lightingr

Specifications of AT90PWM1-16MU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 19
• Program Memory Size: 8KB (8K x 8)
• 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 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 105°C
• Package / Case: 32-QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

19.6.3
19.6.4
190
AT90PWM1
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 “Amplifier 0 Control and Status register – AMP0CSR” on page 202.
can be then subtracted in software from the measurement 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 19-10. Offset Error
•
Offset: The deviation of the first transition (0x000 to 0x001) compared to the ideal transition
(at 0.5 LSB). Ideal value: 0 LSB.
Gain Error: After adjusting for offset, the Gain Error is found as the deviation of the last
transition (0x3FE to 0x3FF) compared to the ideal transition (at 1.5 LSB below maximum).
Ideal value: 0 LSB
Output Code
Offset
Error
V
REF
Input Voltage
n
-1.
). This offset residue
Ideal ADC
Actual ADC
REF
4378C–AVR–09/08
in 2
n
steps