MC68HC08AS32 Datasheet, PDF (51/280 Pages) Motorola, Inc – M68HC08 Family of 8-bit microcontroller units (MCUs)

NOTE:
ADCO — ADC Continuous Conversion Bit
When set, the ADC will convert samples continuously and update the ADR
register at the end of each conversion. Only one conversion is allowed when this
bit is cleared. Reset clears the ADCO bit.
1 = Continuous ADC conversion
0 = One ADC conversion
ADCH[4:0] — ADC Channel Select Bits
ADCH4, ADCH3, ADCH2, ADCH1, and ADCH0 form a 5-bit field which is used
to select one of the ADC channels. The five channel select bits are detailed in
Table 3-1. Care should be taken when using a port pin as both an analog and
a digital input simultaneously to prevent switching noise from corrupting the
analog signal. (See Table 3-1.)
The ADC subsystem is turned off when the channel select bits are all set to one.
This feature allows for reduced power consumption for the MCU when the ADC
is not used. Reset sets all of these bits to a logic 1.
Recovery from the disabled state requires one conversion cycle to stabilize.
Table 3-1. Mux Channel Select
ADCH4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
ADCH3
ADCH2
ADCH1
0
0
0
0
0
0
0
0
1
0
0
1
0
1
0
0
1
0
0
1
1
0
1
1
1
0
0
1
0
0
1
0
1
1
0
1
1
1
0
1
1
0
1
1
1
Range 01111 ($0F) to 11010 ($1A)
1
0
1
1
1
0
1
1
0
1
1
1
1
1
1
ADCH0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Input Select
PTB0/ATD0
PTB1/ATD1
PTB2/ATD2
PTB3/ATD3
PTB4/ATD4
PTB5/ATD5
PTB6/ATD6
PTB7/ATD7
PTD0/ATD8
PTD1/ATD9
PTD2/ATD10
PTD3/ATD11
PTD4/ATD12
PTD5/ATD13
PTD6/ATD14/TCLK
Unused⁽¹⁾
Reserved
Unused⁽¹⁾
V_REFH(2)
V_SSA/V_REFL(2)
ADC Power Off
1. If any unused channels are selected, the resulting ADC conversion will be unknown.
2. The voltage levels supplied from internal reference nodes as specified in the table are used to verify
the operation of the ADC converter both in production test and for user applications.
MC68HC08AS32 — Rev. 4.1
Freescale Semiconductor
Data Sheet
51