MC68HC05P18 Datasheet, PDF (82/144 Pages) Freescale Semiconductor, Inc – Advance Information

Freescale Semiconductor, Inc.
Analog-to-Digital (A/D) Converter
9.4.3 Multi-Channel Operation
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.
9.5 A/D Status and Control Register
The ADSC register reports the completion of A/D conversion and
provides control over oscillator selection, analog subsystem power, and
input channel selection. See Figure 9-1.
Address: $001E
Bit 7
6
5
4
3
2
1
Bit 0
Read: CC
Write:
0
R
ADON
0
CH2
CH1
CH0
Reset: 0
0
0
0
0
0
0
0
= Unimplemented
R = Reserved
Figure 9-1. A/D Status and Control Register (ADSC)
CC — Conversion Complete Bit
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 has been started, conversions of the selected channel
will continue every 32 PH2 clock cycles until the ADSC register is
written to again. During continuous conversion operation, the ADC
register will be updated with new data and the CC bit set every 32
PH2 clock cycles. Also, data from the previous conversion will be
overwritten regardless of the state of the CC bit.
Reserved
This bit is not used currently. It can be read or written, but does not
control anything.
Advance Information
82
MC68HC(8)05P18 — Rev. 2.0
Analog-to-Digital (A/D) Converter
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