C167CS-L datasheet(34/81 Pages) INFINEON

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C167CS-4R

C167CS-L

Data Sheet

V2.2, 2001-08

A/D Converter

For analog signal measurement, a 10-bit A/D converter with 24 multiplexed input

channels (16 standard channels and 8 extension channels) and a sample and hold

circuit has been integrated on-chip. It uses the method of successive approximation. The

sample time (for loading the capacitors) and the conversion time is programmable and

can so be adjusted to the external circuitry.

Overrun error detection/protection is provided for the conversion result register

(ADDAT): either an interrupt request will be generated when the result of a previous

conversion has not been read from the result register at the time the next conversion is

complete, or the next conversion is suspended in such a case until the previous result

has been read.

For applications which require less than 24 analog input channels, the remaining

channel inputs can be used as digital input port pins.

The A/D converter of the C167CS supports four different conversion modes. In the

standard Single Channel conversion mode, the analog level on a specified channel is

sampled once and converted to a digital result. In the Single Channel Continuous mode,

the analog level on a specified channel is repeatedly sampled and converted without

software intervention. In the Auto Scan mode, the analog levels on a prespecified

number of channels (standard or extension) are sequentially sampled and converted. In

the Auto Scan Continuous mode, the number of prespecified channels is repeatedly

sampled and converted. In addition, the conversion of a specific channel can be inserted

(injected) into a running sequence without disturbing this sequence. This is called

Channel Injection Mode.

The Peripheral Event Controller (PEC) may be used to automatically store the

conversion results into a table in memory for later evaluation, without requiring the

overhead of entering and exiting interrupt routines for each data transfer.

After each reset and also during normal operation the ADC automatically performs

calibration cycles. This automatic self-calibration constantly adjusts the converter to

changing operating conditions (e.g. temperature) and compensates process variations.

These calibration cycles are part of the conversion cycle, so they do not affect the normal

operation of the A/D converter.

In order to decouple analog inputs from digital noise and to avoid input trigger noise

those pins used for analog input can be disconnected from the digital IO or input stages

under software control. This can be selected for each pin separately via registers

P5DIDIS (Port 5 Digital Input Disable) and P1DIDIS (PORT1 Digital Input Disable).

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