MC9S12P128 Datasheet, PDF (43/564 Pages) Freescale Semiconductor, Inc – S12 Microcontrollers

Device Overview MC9S12P-Family
1.9.1 Chip Configuration Summary
The different modes and the security state of the MCU affect the debug features (enabled or disabled).
The operating mode out of reset is determined by the state of the MODC signal during reset (see Table 1-
10). The MODC bit in the MODE register shows the current operating mode and provides limited mode
switching during operation. The state of the MODC signal is latched into this bit on the rising edge of
RESET.
Table 1-10. Chip Modes
Chip Modes
Normal single chip
Special single chip
MODC
1
0
1.9.1.1 Normal Single-Chip Mode
This mode is intended for normal device operation. The opcode from the on-chip memory is being
executed after reset (requires the reset vector to be programmed correctly). The processor program is
executed from internal memory.
1.9.1.2 Special Single-Chip Mode
This mode is used for debugging single-chip operation, boot-strapping, or security related operations. The
background debug module BDM is active in this mode. The CPU executes a monitor program located in
an on-chip ROM. BDM firmware waits for additional serial commands through the BKGD pin.
S12P-Family Reference Manual, Rev. 1.12
Freescale Semiconductor
43