Z8F6421PM020SC Datasheet, PDF (194/299 Pages) Zilog, Inc. – High Performance 8-Bit Microcontrollers Z8 Encore-R 64K Series

Z8 Encore!^® 64K Series
Product Specification
174
1. Enable the desired analog input by configuring the general-purpose I/O pins for
alternate function. This disables the digital input and output driver.
2. Write to the ADC Control register to configure the ADC for continuous conversion.
The bit fields in the ADC Control register may be written simultaneously:
– Write to the ANAIN[3:0] field to select one of the 12 analog input sources.
– Set CONT to 1 to select continuous conversion.
– Write to the VREF bit to enable or disable the internal voltage reference generator.
– Set CEN to 1 to start the conversions.
3. When the first conversion in continuous operation is complete (after 5129 system
clock cycles, plus the 40 cycles for power-up, if necessary), the ADC control logic
performs the following operations:
– CEN resets to 0 to indicate the first conversion is complete. CEN remains 0 for all
subsequent conversions in continuous operation.
– An interrupt request is sent to the Interrupt Controller to indicate the conversion is
complete.
4. Thereafter, the ADC writes a new 10-bit data result to {ADCD_H[7:0],
ADCD_L[7:6]} every 256 system clock cycles. An interrupt request is sent to the
Interrupt Controller when each conversion is complete.
5. To disable continuous conversion, clear the CONT bit in the ADC Control register
to 0.
DMA Control of the ADC
The Direct Memory Access (DMA) Controller can control operation of the ADC includ-
ing analog input selection and conversion enable. For more information on the DMA and
configuring for ADC operations refer to the chapter Direct Memory Access Controller
on page 161.
PS019915-1005
Analog-to-Digital Converter