MAC7200 datasheet(786/976 Pages) FREESCALE

786 / 976 page

Functional Description

MAC7200 Microcontroller Family Reference Manual, Rev. 2

708

Freescale Semiconductor

Figure 32-24. Pulse/Edge Accumulation single-shot mode example

32.13.1.1.8

Pulse/Edge Counting (PEC) Mode

The PEC mode returns the amount of pulses or edges detected on the input for a desired time window.

MODE[0] bit selects between continuos or single shot operation.

Triggering of the internal counter is done by a rising or falling edge or both edges on the input signal. The

polarity and the triggering edge is selected by EDSEL and EDPOL bits in UCCRn register.

cleared and it is ready to start counting input events. When the time base matches comparator B, the

internal counter is disabled and its content is transferred to register A2. At the same time the FLAG bit is

set. Reading registers MSTCNTn or A2 returns the amount of detected pulses.

For continuos operation (MODE[0] cleared), the next match between comparator A and the selected time

base clears the internal counter and counting is enabled again. In order to guarantee coherent

measurements when reading UCCNTn after the flag is set, the software must check if the time base value

is out of the time interval defined by registers A1 and B1. Alternatively register A2 always holds the latest

available measurement providing coherent data at any time after the first FLAG had occurred. This register

is addressed by the alternate address ALTAn.

For single shot operation (MODE[0] set), the next match between comparator A and the selected time base

has no effect, until a new write to register A is performed. The UCCNTn content is also transferred to

$FFFFFF

$000000

UCCNTn1

Time

write to A1

selected counter bus

$000400

A1 value3

$001500

$xxxxxx

value4

$000400

$xxxxxx

value

$000090

$xxxxxx

value5

$xxxxxx

$001500

$000090

FLAG set event

$001500

input signal2

A1 events

Notes:

4. UCAn = A2 (when reading)

5. UCBn = B1

3. UCAn = A1 (when writing)

2. After input filter

events

$000400

1. Cleared on the first input event after writing to register A1

A1 Match

MODE[0]= 1

MAC7200 Datasheet(PDF) 786 Page - Freescale Semiconductor, Inc

MAC7200 Datasheet(HTML) 786 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL