MC9RS08KA8RM Datasheet, PDF (110/190 Pages) Freescale Semiconductor, Inc – MC9RS08KA8 Features

Analog-to-Digital Converter (RS08ADC10V1)
For example, you could use the following equation conversion time for a single conversion in 10-bit mode:
where:
23 ADCK cyc
Conversion time =
8 MHz/1
+
5 bus cyc
8 MHz
Number of bus cycles = 3.5 μs x 8 MHz = 28 cycles
– Mode: 10-Bit
– Input Clock Source: Bus Clock
– Input Clock Ratio: Divide by 1
– Bus Frequency: 8 MHz
– Conversion Time: 3.5 μs
= 3.5 μs
NOTE
The ADCK frequency must be between f_ADCK minimum and f_ADCK
maximum to meet ADC specifications.
10.4.5 Automatic Compare Function
The compare function can be configured to check for an upper or lower limit. After the input is sampled
and converted, the result is added to the two’s complement of the compare value (ADCCVH and
ADCCVL). When comparing to an upper limit (ACFGT = 1), if the result is greater-than or equal-to the
compare value, COCO is set. When comparing to a lower limit (ACFGT = 0), if the result is less than the
compare value, COCO is set. The value generated by the addition of the conversion result and the two’s
complement of the compare value is transferred to ADCRH and ADCRL.
Following a conversion where the compare function is enabled, and the compare condition is not true,
COCO is not set and no data is transferred to the result registers. An ADC interrupt is generated upon the
setting of COCO if the ADC interrupt is enabled (AIEN = 1).
NOTE
The compare function can be used to monitor the voltage on a channel while
the MCU is in wait or stop mode. The ADC interrupt wakes the MCU when
the compare condition is met.
10.4.6 MCU Wait Mode Operation
The WAIT instruction puts the MCU in a lower power-consumption standby mode. Recovery is very fast
because the clock sources remain active. If a conversion is in progress when the MCU enters wait mode,
it continues until completion. Conversions can be initiated while the MCU is in wait mode by means of
the hardware trigger or if continuous conversions are enabled.
MC9RS08KA8 Series Reference Manual, Rev. 3
110
Freescale Semiconductor