MC908JL8CDWE Datasheet, PDF (149/212 Pages) Freescale Semiconductor, Inc – Microcontrollers

I/O Registers
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
ADCH[4:0] form a 5-bit field which is used to select one of the ADC channels. The five channel select
bits are detailed in the following table. 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 10-1.)
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.
NOTE
Recovery from the disabled state requires one conversion cycle to stabilize.
Table 10-1. MUX Channel Select
ADCH4 ADCH3 ADCH2 ADCH1 ADCH0 ADC Channel
Input Select
0
0
0
0
0
ADC0
0
0
0
0
1
ADC1
0
0
0
1
0
ADC2
0
0
0
1
1
ADC3
0
0
1
0
0
ADC4
0
0
1
0
1
ADC5
0
0
1
1
0
ADC6
PTB0
PTB1
PTB2
PTB3
PTB4
PTB5
PTB6
0
0
1
1
1
ADC7
PTB7
0
1
0
0
0
ADC8
PTD3
0
1
0
0
1
ADC9
PTD2
0
1
0
1
0
ADC10
PTD1
0
1
0
1
1
ADC11
PTD0
0
1
1
0
0
ADC12
ADC12/T2CLK
0
1
1
0
1
:
:
:
:
:
—
Unused⁽¹⁾
1
1
0
1
0
1
1
0
1
1
—
Reserved
1
1
1
0
0
—
Reserved
1
1
1
0
1
1
1
1
1
0
V_DD(2)
V_SS(2)
1
1
1
1
1
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.
MC68HC908JL8/JK8 • MC68HC08JL8/JK8 • MC68HC908KL8 Data Sheet, Rev. 3.1
Freescale Semiconductor
149