Analog-to-Digital Converter (ADC)
I/O Registers
MC68HC908MR16/MC68HC908MR32 — Rev. 4.0 Advance Information
MOTOROLA Analog-to-Digital Converter (ADC) 349
19.7.6.3 Grounding
In cases where separate power supplies are used for anal og and d igital
power, the ground connection between these supplies should be at the
VSSA pin. This should be the only ground connection between these
supplies if possible. The VSSA pin makes a good single point ground
location. Connect the VREFL pin to the same potential as VSSAD at the
single point ground location.
19.8 I/O Registers
These I/O registers control and monitor operation of the ADC:
ADC status and control register, ADSCR
ADC data registers, ADRH and ARDL
ADC clock register, ADCLK
19.8.1 ADC Status and Control Register
This section describes the function of the ADC status and control
register (ADSCR). Writing ADSCR aborts the current conversion and
initiates a new conversion.
COCO — Conversions Complete Bit
When AIEN bit is a logic 0, the COCO is a read-only bit which is set
each time a conversion is completed except in the continuous
conversion mode where it is set after the first conversion. This bit is
cleared whenever the ADC status and control register is written or
whenever the ADC data register is read.
Address: $0040
Bit 7654321Bit 0
Read: COCO AIEN ADCO ADCH4 ADCH3 ADCH2 ADCH1 ADCH0
Write:
Reset:00011111
Figure 19-3. ADC Status and Control Register (ADSCR)