Z8F0113HJ005EG Datasheet, PDF (139/245 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F0823 Series
Product Specification
124
– CEN resets to 0 to indicate the conversion is complete
6. If the ADC remains idle for 160 consecutive system clock cycles, it is automatically
powered-down.
Continuous Conversion
When configured for continuous conversion, the ADC continuously performs an analog-
to-digital conversion on the selected analog input. Each new data value over-writes the
previous value stored in the ADC Data registers. An interrupt is generated after each con-
version.
Caution: In CONTINUOUS Mode, ADC updates are limited by the input signal bandwidth of the
ADC and the latency of the ADC and its digital filter. Step changes at the input are not
detected at the next output from the ADC. The response of the ADC (in all modes) is lim-
ited by the input signal bandwidth and the latency.
Observe the following steps for setting up the ADC and initiating continuous conversion:
1. Enable the acceptable analog input by configuring the general-purpose I/O pins for
alternate function. This action disables the digital input and output driver.
2. Write the ADC Control/Status Register 1 to configure the ADC:
– Write the REFSELH bit of the pair {REFSELH, REFSELL} to select the internal
voltage reference level or to disable the internal reference. The REFSELH bit is
contained in the ADC Control/Status Register 1.
3. Write to the ADC Control Register 0 to configure the ADC for continuous conversion.
The bit fields in the ADC Control Register can be written simultaneously:
– Write to the ANAIN[3:0] field to select from the available analog input sources
(different input pins available depending on the device).
– Set CONT to 1 to select continuous conversion.
– If the internal VREF must be output to a pin, set the REFEXT bit to 1. The inter-
nal voltage reference must be enabled in this case.
– Write the REFSELL bit of the pair {REFSELH, REFSELL} to select the internal
voltage reference level or to disable the internal reference. The REFSELL bit is
contained in ADC Control Register 0.
– Set CEN to 1 to start the conversions.
PS024315-1011
PRELIMINARY
Operation