Rainbow Electronics AT90LS8535 - Manual (Page 72)

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AT90S/LS8535
1041H–11/01
2. Enter Idle Mode. The ADC will start a conversion once the CPU has been halted.
3. If no other interrupts occur before the ADC conversion completes, the ADC inter-
rupt will wake up the MCU and execute the ADC Conversion Complete Interrupt
routine.
ADC Multiplexer Select
Register – ADMUX
• Bits 7..3 – Res: Reserved Bits
These bits are reserved bits in the AT90S8535 and always read as zero.
• Bits 2..0 – MUX2..MUX0: Analog Channel Select Bits 2-0
The value of these three bits selects which analog input ADC7..0 is connected to the
ADC. See Table 27 for details.
If these bits are changed during a conversion, the change will not go into effect until this
conversion is complete (ADIF in ADCSR is set).
ADC Control and Status
Register – ADCSR
• Bit 7 – ADEN: ADC Enable
Writing a logical “1” to this bit enables the ADC. By clearing this bit to zero, the ADC is
turned off. Turning the ADC off while a conversion is in progress will terminate this
conversion.
• Bit 6 – ADSC: ADC Start Conversion
In Single Conversion Mode, a logical “1” must be written to this bit to start each conver-
sion. In Free Running Mode, a logical “1” must be written to this bit to start the first
conversion. The first time ADSC has been written after the ADC has been enabled or if
ADSC is written at the same time as the ADC is enabled, an extended conversion will
precede the initiated conversion. This extended conversion performs initialization of the
ADC.
Bit 7 6 5 4 3 2 1 0
$07 ($27) – – – – – MUX2 MUX1 MUX0 ADMUX
Read/Write R R R R R R/W R/W R/W
Initial Value 0 0 0 0 0 0 0 0
Table 27. Input Channel Selections
MUX2.0 Single-ended Input
000 ADC0
001 ADC1
010 ADC2
011 ADC3
100 ADC4
101 ADC5
110 ADC6
111 ADC7
Bit 7 6 5 4 3 2 1 0
$06 ($26) ADEN ADSC ADFR ADIF ADIE ADPS2 ADPS1 ADPS0 ADCSR
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value 0 0 0 0 0 0 0 0