300
CHAPTER 18 8/10-BIT A/D CONVERTER
18.7
Notes on the 8/10-Bit A/D Converter
Notes on using the 8/10-bit A/D converter.
■
Usage Notes on the 8/10-bit A/D Converter
●
Analog input pin
The A/D input pins are also used as the I/O pins of ports 6 and B. The corresponding Data Direction
Register (DDR6 and DDRB) and the Analog Input Enable Register (ADER) determine which pin is used
for which purpose.
To use a pin as analog input, write "0" to the corresponding bit of DDR6, resp. of DDRB, and thereby
change the port setting to input. Then, set the analog input mode (ADEx = 1) in the ADER register and
determine the input gate of the port.
If an intermediate-level signal is input in the port input mode (ADEx = 0), a leakage current flows through
the gate.
●
Note on using an internal timer
To start the A/D converter with an internal timer, set the STS1 and STS0 bits of A/D control status register
1 (ADCS1) accordingly. Set the input value of the internal timer at the inactive level ("L" for the internal
timer). Otherwise, operation may start concurrently with writing to the ADCS register.
●
Sequence of turning on the A/D converter and analog input
Do not turn on power to the A/D converter (AV
CC
, AVRH, AVRL) and to the analog inputs (AN0 to AN7)
before the digital power supply (V
CC
) has been turned on.
Do not turn off the digital power supply (V
CC
) before power to the A/D converter and the analog inputs has
been turned off.
●
Supply voltage to the A/D converter
The supply voltage to the A/D converter (AV
CC
) must not exceed the digital power supply (V
CC
);
otherwise, latch-up may occur.
Summary of Contents for MB90390 Series
Page 2: ......
Page 4: ......
Page 17: ...xiii APPENDIX D List of Interrupt Vectors 690 INDEX 695 ...
Page 18: ...xiv ...
Page 132: ...104 CHAPTER 5 CLOCKS ...
Page 152: ...124 CHAPTER 6 CLOCK MODULATOR ...
Page 210: ...182 CHAPTER 11 TIME BASE TIMER ...
Page 218: ...190 CHAPTER 12 WATCHDOG TIMER ...
Page 264: ...236 CHAPTER 14 16 BIT RELOAD TIMER WITH EVENT COUNT FUNCTION ...
Page 274: ...246 CHAPTER 15 WATCH TIMER ...
Page 306: ...278 CHAPTER 17 DTP EXTERNAL INTERRUPTS ...
Page 338: ...310 CHAPTER 18 8 10 BIT A D CONVERTER ...
Page 364: ...336 CHAPTER 19 UART0 UART1 ...
Page 398: ...370 CHAPTER 20 UART2 UART3 Figure 20 5 2 ORE Set Timing Receive data RDRF ORE ...
Page 432: ...404 CHAPTER 20 UART2 UART3 ...
Page 482: ...454 CHAPTER 22 SERIAL I O ...
Page 560: ...532 CHAPTER 24 STEPPING MOTOR CONTROLLER ...
Page 582: ...554 CHAPTER 27 ROM MIRRORING MODULE ...
Page 632: ...604 CHAPTER 29 EXAMPLES OF SERIAL PROGRAMMING CONNECTION ...
Page 722: ...694 APPENDIX ...
Page 723: ...695 INDEX The index follows on the next page This is listed in alphabetic order ...
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