Start-Up Process - NXP Semiconductors MKL27Z128VFM4 Reference Manual

Table of Contents

Table 13-3. Configuration Fields for the Kinetis Bootloader (continued)

The flash sector containing the BCA should not be located in

the execute-only region, because the Kinetis bootloader cannot

read an execute-only region.

The first configuration field 'tag' is a tag value or magic number. The tag value must be

set to 'kcfg' for the bootloader configuration data to be recognized as valid. If tag-field

verification fails, then the Kinetis Bootloader assumes that the flash is not initialized and

uses a predefined default configuration. The tag value is treated as a character string, so

bytes 0-3 must be set as shown in the table.

The flags in the clockFlags configuration field are enabled if the corresponding bit is

cleared (0).

13.3.3 Start-up Process

Any of the following conditions will force the hardware to start the Kinetis Bootloader:

• FOPT [7] is set to 1. This forces the ROM to run out of reset.

Freescale Semiconductor, Inc.

Size (bytes)

Table 13-4. tag Configuration Field

Table 13-5. clockFlags Configuration Field

KL27 Sub-Family Reference Manual , Rev. 5, 01/2016

Configuration Field

Enable high speed mode (i.e., 48 MHz).

Chapter 13 Kinetis ROM Bootloader

tag Byte Value