Atmega32(l) – Rainbow Electronics ATmega32L User Manual

Page 236

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236

ATmega32(L)

2503C–AVR–10/02

Using this algorithm, the timing constraint on the HOLD signal constrains the TCK clock
frequency. As the algorithm keeps HOLD high for five steps, the TCK clock frequency
has to be at least five times the number of scan bits divided by the maximum hold time,
t

hold,max

.

Table 93. Algorithm for Using the ADC

Step

Actions

ADCEN

DAC

MUXEN

HOLD

PRECH

PA3.
Data

PA3.
Control

PA3.
Pullup_
Enable

1

SAMPLE
_PRELO
AD

1

0x200

0x08

1

1

0

0

0

2

EXTEST

1

0x200

0x08

0

1

0

0

0

3

1

0x200

0x08

1

1

0

0

0

4

1

0x123

0x08

1

1

0

0

0

5

1

0x123

0x08

1

0

0

0

0

6

Verify the
COMP bit
scanned
out to be
0

1

0x200

0x08

1

1

0

0

0

7

1

0x200

0x08

0

1

0

0

0

8

1

0x200

0x08

1

1

0

0

0

9

1

0x143

0x08

1

1

0

0

0

10

1

0x143

0x08

1

0

0

0

0

11

Verify the
COMP bit
scanned
out to be
1

1

0x200

0x08

1

1

0

0

0

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