MC68HC05PV8 Datasheet, PDF (140/196 Pages) Freescale Semiconductor, Inc – Techinal Data - rev 1.9

Technical Data
Freescale Semiconductor, Inc.
3. If the system clock is running faster than the RC oscillator, the RC
oscillator should be turned off, and the system clock used as the
conversion clock.
10.6 A/D Registers
10.6.1 A/D Status and Control Register (ADSCR)
The following paragraphs describe the function of the A/D status and
control register.
$000F Bit 7
6
5
4
3
2
1
Bit 0
Read: COCO
ADRC ADON ADTST CH3
CH2
CH1
CH0
Write:
Reset: U
U
U
U
U
U
U
U
Figure 10-1 A/D Status and Control Register (ADSCR)
COCO – Conversion Complete
This read-only status bit is set when a conversion is completed,
indicating that the A/D data register contains valid results. This bit is
cleared whenever the A/D status and control register is written and a
new conversion automatically started, or whenever the A/D register is
read. Once a conversion has been started by writing to the A/D status
and control register, conversions of the selected channel will continue
every 32 cycles until the A/D status and control register is written
again. In this continuous conversion mode, the A/D data register will
be filled with new data, and the COCO bit set, every 32 cycles. Data
from the previous conversion will be overwritten regardless of the
state of the COCO bit prior to writing.
ADRC – RC Oscillator On
When ADRC is set, the A/D section runs on the internal RC oscillator
instead of the CPU clock. The RC oscillator requires a time t_RCON to
stabilize and results can be inaccurate during this time. See 10.5
Internal and Master Oscillator.
Technical Data
MC68HC(8)05PV8/A — Rev. 1.9
Analog to Digital Converter
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