C515 Datasheet, PDF (32/55 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

C515
8-Bit A/D Converter
The C515 provides an A/D converter with the following features:
– Eight multiplexed input channels
– The possibility of using the analog inputs (port 6) also as digital inputs
– Programmable internal reference voltages (16 steps each) via resistor array
– 8-bit resolution within the selected reference voltage range
– Internal start-of-conversion trigger
– Interrupt request generation after each conversion
For the A/D conversion, the method of successive approximation via capacitor array is used. The
externally applied reference voltage range has to be held on a fixed value within the specifications
(see section "A/D Converter Characteristics" in this data sheet). The internal reference voltages can
be varied to reduce the reference voltage range of the A/D converter and thus to achieve a higher
resolution. Figure 14 shows a block diagram of the A/D converter.
Semiconductor Group
32
1997-08-01