MAC7200 datasheet(810/976 Pages) FREESCALE

810 / 976 page

Functional Description

MAC7200 Microcontroller Family Reference Manual, Rev. 2

732

Freescale Semiconductor

Figure 32-53. OPWMB Mode with Active Output Disable

Figure 32-54 shows a waveform changing from 100% to 0% duty cycle. EDPOL in this case is zero. In

this example B1 is programmed to the same value as the period of the external selected time base.

Figure 32-54. OPWMB Mode from 100% to 0% Duty Cycle

In Figure 32-54 if B1 is set to a value lower than 0x000008 it is not possible to achieve 0% duty cycle by

only changing A1 register value. Since B1 matches have precedence over A1 matches the output pin

transitions to the opposite of EDPOL bit at B1 match. Note also that if B1 is set to 0x000009, for instance,

B1 match does not occur, thus a 0% duty cycle signal is generated.

32.13.1.2 Input Programmable Filter (IPF)

The IPF ensures that only valid input pin transitions are received by the Unified Channel edge detector. A

block diagram of the IPF is shown in Figure 32-55.

The IPF is a 5-bit programmable up counter that is incremented by the selected clock source, according to

bits IF[3:0] in UCCRn register.

EDPOL = 0

cycle n

cycle n+1

cycle n+2

A1 value

B1 value

B2 value

$000008

$000002

$000006

$000008

$000001

Selected

$000004

$000006

MODE[0]= 1

A2 value

$000002

$000004

$000006

$000002

$000004

$000006

$000008

$000006

Output pin

write to B2

write to A2

Match A1

Match B1

due to B1 match cycle n-1

FLAG set event

Output Disable

Counter Bus

$000008

$000007

$000006

$000005

$000004

$000003

$000002

$000001

$000000

100%

Selected

EDPOL = 0

A1 value

B1 value

Output pin

$000008

Prescaler = 1

cycle 1

cycle 2

cycle 3

cycle 4

cycle 5

cycle 6

cycle 7

cycle 8

cycle 9

counter bus

$000007

$000006

$000005

$000004

$000003

$000002

$000001

$000000

A2 value

MAC7200 Datasheet(PDF) 810 Page - Freescale Semiconductor, Inc

MAC7200 Datasheet(HTML) 810 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