MC68HC08AS32A Datasheet, PDF (58/296 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Analog-to-Digital Converter (ADC)
3.7.1 ADC Status and Control Register
The following paragraphs describe the function of the ADC status and control
register.
Address: $0038
Bit 7
6
5
4
3
2
1
Read: COCO
AIEN
ADCO ADCH4 ADCH3 ADCH2 ADCH1
Write: R
Reset: 0
0
0
1
1
1
1
R
= Reserved
Figure 3-3. ADC Status and Control Register (ADSCR)
Bit 0
ADCH0
1
COCO — Conversions Complete Bit
In non-interrupt mode (AIEN = 0), COCO is a read-only bit that is set at the end
of each conversion. COCO will stay set until cleared by a read of the ADC data
register. Reset clears this bit.
In interrupt mode (AIEN = 1), COCO is a read-only bit that is not set at the end
of a conversion. It always reads as a logic 0.
1 = Conversion completed (AIEN = 0)
0 = Conversion not completed (AIEN = 0) or CPU interrupt enabled
(AIEN = 1)
NOTE: The write function of the COCO bit is reserved. When writing to the ADSCR
register, always have a 0 in the COCO bit position.
AIEN — ADC Interrupt Enable Bit
When this bit is set, an interrupt is generated at the end of an ADC conversion.
The interrupt signal is cleared when the data register is read or the status/control
register is written. Reset clears the AIEN bit.
1 = ADC interrupt enabled
0 = ADC interrupt disabled
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
ADCH4, ADCH3, ADCH2, ADCH1, and ADCH0 form a 5-bit field which is used
to select one of the ADC channels. The five channel select bits are detailed in
Table 3-1. 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 3-1.)
Data Sheet
58
Analog-to-Digital Converter (ADC)
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MC68HC08AS32A — Rev. 1
MOTOROLA