MAC7200 datasheet(811/976 Pages) FREESCALE

811 / 976 page

Functional Description

MAC7200 Microcontroller Family Reference Manual, Rev. 2

Freescale Semiconductor

733

Figure 32-55. lnput Programmable Filter submodule diagram

The input signal is synchronized by system clock. When a state change occurs in this signal, the 5-bit

counter starts counting up. As long as the new state is stable on the pin, the counter remains incrementing.

If a counter overflows occurs, the new pin value is validated. In this case, it is transmitted as a pulse edge

to the edge detector. If the opposite edge appears on the pin before validation (overflow), the counter is

reset. At the next pin transition, the counter starts counting again. Any pulse that is shorter than a full range

of the masked counter is regarded as a glitch and it is not passed on to the edge detector. A timing diagram

of the input filter is shown in Figure 32-56.

Figure 32-56. Input Programmable filter example

32.13.1.3 Clock Prescaler (CP)

The CP divides the GCP output signal to generate a clock enable for the internal counter of the Unified

Channels. It is a programmable 2-bit down counter. The GCP output signal is prescaled by the value

defined in Table 32-7 according to the UCPRE[1:0] bits in UCCRn register. The output is clocked every

time the counter reaches zero. Counting is enabled by setting the UCPREN bit in the UCCRn. The counter

can be stopped at any time by clearing this bit, thereby stopping the internal counter in the Unified

Channel.

32.13.1.4 Effect of Freeze on the Unified Channel

When in debug mode, FRZ bit in the MCR register and the FREN bit in the UCCRn are both set, the

internal counter and Unified Channel capture and compare functions are halted. The UC is frozen in its

current state.

IF3

filter out

ipg_clk

Prescaled Clock

IF2

IF1

IF0

clk

FCK

EMIOSI

5-bit up counter

clock

Time

selected clock

EMIOSI

5-bit counter

filter out

IF [3:0]= 0010

MAC7200 Datasheet(PDF) 811 Page - Freescale Semiconductor, Inc

MAC7200 Datasheet(HTML) 811 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