MAC7200 datasheet(153/976 Pages) FREESCALE

153 / 976 page

Effects of Reset

MAC7200 Microcontroller Family Reference Manual, Rev. 2

Freescale Semiconductor

— Power on the MAC72xx. This will reset the ARM7 core, EICE and Nexus.

— While RESET is asserted, drive the Nexus Present (PF1) and Nexus Port Select (PF0) lines to

enable/disable a particular Nexus Port

— The Nexus is reset by cycling through the Test Reset state in the TAP controller

— Once the Nexus resets, it latches in the EVTI bit from the selected Nexus port.

6.7

Effects of Reset

6.7.1

Hardware Configuration

When a POR or System Reset occurs, the following pins are sampled while the RESET pin is asserted

(low) in order to determine the configuration of the system:

•

MODA (PD1)

•

MODB (PD0)

•

NEXPORTSEL (PF0)

•

NEXPRESENT (PF1)

•

AUTOACK (PF2)

•

PORTSIZE (PF3)

In addition, on a POR or System Reset, the security state of the system is determined from the System

Censor word in the Flash (See Section 18.7.9, “Flash Security”). This means that a currently secured

system may come out of reset as secured, and vice-versa.

The oscillator mode selection is done via the XCLKS hardware configuration pin (PD2), but only during

the following conditions:

•POR, or

•

System Reset after a loss of clock has occurred.

6.7.2

When a POR or System Reset occurs, MCU registers and control bits are changed to known start-up states.

Refer to the respective module chapters for register reset states.

When a Debug Reset occurs, the following registers are reset:

•

EICE registers. Please refer to the ARM7 documentation for more information.

•

Nexus registers. Please refer to Chapter 11, “A7S Nexus3 Module” for more information.

•

TAP State Machine. Please refer to the ARM7 documentation for more information.

6.7.3

Peripheral Disabled State

Following a Power on Reset or a System Reset, the following peripheral modules are disabled, and must

be enabled before they can be used:

•eSCI

MAC7200 Datasheet(PDF) 153 Page - Freescale Semiconductor, Inc

MAC7200 Datasheet(HTML) 153 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