Signal Connection Considerations

never transfer a full-scale value. If VRL is less than VSSA, the sample amplifier can never transfer a 0 value.

Figure 27-45shows the results of reference voltages outside the range defined by VDDA and VSSA. At the top of the input signal range, VDDA is 10 mV lower than VRH. This results in a maximum obtainable 10-bit conversion value 0x03fe. At the bottom of the signal range, VSSA is 15 mV higher than VRL, resulting in a minimum obtainable 10-bit conversion value of 0x0003.

10-bit Result (Hexadecimal)

3FF

3FE

3FD

3FC

3FB

3FA

8

7

6

5

4

3

2

1

0

.010

.020

.030

5.100

5.110

5.120

5.130

Inputs in Volts (VRH = 5.120 V, VRL = 0 V)

Figure 27-45. Errors Resulting from Clipping

27.9.3 Conversion Timing Schemes

This section contains some conversion timing examples. Figure 27-46shows the timing for basic conversions where it is assumed that:

Q1 begins with CCW0 and ends with CCW3.

CCW0 has pause bit set.

CCW1 does not have pause bit set.

External trigger rising edge for Q1

CCW4 = BQ2 and Q2 is disabled.

Q1 RES shows relative result register updates.

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MCF5282 User’s Manual

MOTOROLA

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Image 648
Motorola MCF5282, MCF5281 user manual Conversion Timing Schemes, Errors Resulting from Clipping