Datasheet

Section 17 A/D Converter
Rev.7.00 Mar. 18, 2009 page 816 of 1136
REJ09B0109-0700
17.5 Interrupt Source
The A/D converter generates an A/D conversion end interrupt (ADI) at the end of A/D conversion.
Setting the ADIE bit to 1 enables an ADI interrupt requests while the bit ADF in ADCSR is set to
1 after A/D conversion is completed. The DTC or DMAC can be activated by an ADI interrupt.
Having the converted data read by the DTC or DMAC in response to an ADI interrupt enables
continuous conversion to be achieved without imposing a load on software.
Table 17.5 A/D Converter Interrupt Source
Name Interrupt Source Interrupt Flag DTC Activation DMAC Activation
ADI End of conversion ADF Possible Possible
17.6 A/D Conversion Accuracy Definitions
This LSI’s A/D conversion accuracy definitions are given below.
• Resolution
The number of A/D converter digital output codes
• Quantization error
The deviation inherent in the A/D converter, given by 1/2 LSB (see figure 17.4).
• Offset error
The deviation of the analog input voltage value from the ideal A/D conversion characteristic
when the digital output changes from the minimum voltage value B'0000000000 (H'000) to
B'0000000001 (H'001) (see figure 17.5).
• Full-scale error
The deviation of the analog input voltage value from the ideal A/D conversion characteristic
when the digital output changes from B'1111111110 (H'3FE) to B'1111111111 (H'3FF) (see
figure 17.5).
• Nonlinearity error
The error with respect to the ideal A/D conversion characteristic between the zero voltage and
the full-scale voltage. Does not include the offset error, full-scale error, or quantization error
(see figure 17.5).
• Absolute precision
The deviation between the digital value and the analog input value. Includes the offset error,
full-scale error, quantization error, and nonlinearity error.