PXD20RM Datasheet, PDF (178/1628 Pages) Freescale Semiconductor, Inc – PXD20 Microcontroller

The RAM location where to download the code can be any 4 byte aligned location starting from the
address 0x4000_0100.
6.5 Functional description
6.5.1 Entering boot modes
The PXD20 detects the boot mode based on external pins and device status (see Figure 6-1).
To boot either from FlexCAN or LINFlex, the device must be forced into an Alternate Boot Loader Mode
via the FAB (Force Alternate Boot Mode) pin which must be asserted before initiating the reset sequence.
The type of alternate boot mode is selected according to the ABS (Alternate Boot Selector) pin (see
Table 6-1).
NOTE
The watchdog (SWT) is disabled at the start of BAM execution. In the case
of an unexpected issue during BAM execution the CPU may be stalled and
it will be necessary to generate an external reset to recover.
The grey blocks represent action done by hardware; the white
ones action done by software (BAM).
Figure 6-1. Boot mode selection
PXD20 Microcontroller Reference Manual, Rev. 1
6-2
Freescale Semiconductor
Preliminary—Subject to Change Without Notice