mc68hc05p18a Freescale Semiconductor, Inc, mc68hc05p18a Datasheet - Page 94

• Manufacturer Part Number: mc68hc05p18a
• Description: Mc68hc05p18a Hcmos Microcontroller Unit
• Manufacturer: Freescale Semiconductor, Inc

Analog-to-Digital (A/D) Converter
11.5.3 Multi-Channel Operation
11.6 A/D Status and Control Register
Technical Data
Address:
An input multiplexer allows the A/D converter to select from one of four
external analog signals. Port C pins PC3–PC6 are shared with the inputs
to the multiplexer.
The A/D status and control register (ADSCR) reports the completion of
A/D conversion and provides control over:
See
CC — Conversion Complete Bit
Reset:
Read:
Write:
•
•
•
This read-only status bit is set when a conversion sequence has
completed and data is ready to be read from the ADC register. CC is
cleared when a channel is selected for conversion, when data is read
from the ADC register, or when the A/D subsystem is turned off. Once
a conversion is started, conversions of the selected channel continue
every 32 PH2 clock cycles until the ADSC register is written to again.
During continuous conversion operation, the ADC register is updated
with new data, and the CC bit is set, every 32 PH2 clock cycles. Also,
data from the previous conversion is overwritten regardless of the
state of the CC bit.
Freescale Semiconductor, Inc.
Figure
For More Information On This Product,
Figure 11-1. A/D Status and Control Register (ADSCR)
Oscillator selection
Analog subsystem power
Input channel selection
$001E
Bit 7
CC
0
Analog-to-Digital (A/D) Converter
11-1.
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= Unimplemented
R
6
0
ADON
5
0
R
4
0
0
= Reserved
3
0
0
CH2
2
0
MC68HC05P18A
CH1
1
0
Bit 0
CH0
0