MAC7200 datasheet(99/976 Pages) FREESCALE

99 / 976 page

External Bus Configuration

MAC7200 Microcontroller Family Reference Manual, Rev. 2

Freescale Semiconductor

The Nexus may be enabled or disabled using the settings described in Table 2-5.

The Nexus Port may be changed only by resetting the device. Please refer to Chapter 8, “Debug” for more

information on configuring and using Nexus.

2.7

External Bus Configuration

If the device and MCU Mode support an external bus, then it may be configured via the PF2 and PF3 pins.

Please refer to Chapter 17, “External Bus Interface (FlexBus)” for more information on configuring and

using the External Bus.

2.8

Low Power Modes

The microcontroller features only a single low power mode:

•

DOZE Mode. In this mode, individual peripherals may be shut down to allow a completely

customizable power consumption profile tailored to the requirements of the application.

Table 2-4. Nexus Port Selection

Reset State Definition

NEXPORTSEL

(PF0)

This bit determines whether the Nexus, if present, resides on the Primary or Secondary Port.

NEXPRESENT

(PF1)

This bit determines whether an external debug system is physically connected to the MAC72xx. Internally, it

is used with NEXUSPORTSEL to place the Nexus Primary or Secondary Port pads into the correct

configuration.

Table 2-5. Nexus Hardware Configuration

NEXPORTSEL

NEXPRESENT

Effect

Nexus is not present.

Nexus is present on the Primary Port.

Nexus is not present.

Nexus is present on the Secondary Port.

Table 2-6. External Bus Configuration

Reset State Definition

AUTOACK

(PF2)

This bit enables the Auto Acknowledge feature for the Global

Chip Select on the External Bus. Internally, this latched value is tied to fb_rst_cfg[2].

PORTSIZE

(PF3)

This bit determines the port size of the External Bus as follows:

08-bit

1 16-bit

Internally this latched value is driven onto fb_rst_cfg[1], while fb_rst_cfg[0] is tied to 1. This precludes the

use of a 32-bit Port size, which is not supported on the MAC72xx. The full encoding for fb_rst_cfg[1:0] is:

00 32-bit

01 8-bit

1x 16-bit

MAC7200 Datasheet(PDF) 99 Page - Freescale Semiconductor, Inc

MAC7200 Datasheet(HTML) 99 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