MC908GR16ACFA FREESCALE [Freescale Semiconductor, Inc], MC908GR16ACFA Datasheet - Page 52

• Manufacturer Part Number: MC908GR16ACFA
• Description: M68HC08 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Analog-to-Digital Converter (ADC)
AIEN — ADC Interrupt Enable Bit
ADCO — ADC Continuous Conversion Bit
ADCH4–ADCH0 — ADC Channel Select Bits
The voltage levels supplied from internal reference nodes, as specified in
Table
applications.
52
When this bit is set, an interrupt is generated at the end of an ADC conversion. The interrupt signal is
cleared when the data register is read or the status/control register is written. Reset clears the AIEN bit.
When set, the ADC will convert samples continuously and update the ADR register at the end of each
conversion. Only one conversion is completed between writes to the ADSCR when this bit is cleared.
Reset clears the ADCO bit.
ADCH4–ADCH0 form a 5-bit field which is used to select one of 32 ADC channels. Only eight
channels, AD7–AD0, are available on this MCU. The channels are detailed in
be taken when using a port pin as both an analog and digital input simultaneously to prevent switching
noise from corrupting the analog signal. See
The ADC subsystem is turned off when the channel select bits are all set to 1. This feature allows for
reduced power consumption for the MCU when the ADC is not being used.
1 = ADC interrupt enabled
0 = ADC interrupt disabled
1 = Continuous ADC conversion
0 = One ADC conversion
3-1, are used to verify the operation of the ADC converter both in production testing and for user
1. If any unused channels are selected, the resulting ADC conversion will be unknown or
ADCH4
Recovery from the disabled state requires one conversion cycle to stabilize.
reserved.
0
0
0
0
0
0
0
0
0
↓
1
1
1
1
ADCH3
0
0
0
0
0
0
0
0
1
↓
1
1
1
1
MC68HC908GR16A Data Sheet, Rev. 1.0
Table 3-1. Mux Channel Select
ADCH2
↓
0
0
0
0
1
1
1
1
0
1
1
1
1
Table
ADCH1
NOTE
↓
0
0
1
1
0
0
1
1
0
0
0
1
1
3-1.
ADCH0
0
1
0
1
0
1
0
1
0
↓
0
1
0
1
(1)
ADC power off
Input Select
PTB0/AD0
PTB1/AD1
PTB2/AD2
PTB3/AD3
PTB4/AD4
PTB5/AD5
PTB6/AD6
PTB7/AD7
Unused
V
V
REFH
REFL
Table
Freescale Semiconductor
3-1. Care should