• When a BGND instruction is executed.
• When encountering a BDC breakpoint.
Background commands are of two types:
• Non-intrusive commands, defined as commands that can be issued while the user
program is running. Non-intrusive commands can be issued through the BKGD pin
while the MCU is in run mode; non-intrusive commands can also be executed when
the MCU is in the active background mode. Non-intrusive commands include:
• Memory access commands
• Memory-access-with-status commands
• BDC register access commands
• The BACKGROUND command
• Active background commands, which can be executed only while the MCU is in
active background mode. Active background commands include commands to:
• Read or write CPU registers
• Trace one user program instruction at a time
• Leave active background mode to return to the user's application program (GO)
The active background mode is used to program a bootloader or user application program
into the flash program memory before the MCU is operated in run mode for the first time.
The active background mode can also be used to erase and reprogram the flash memory
after it has been previously programmed.
10.4.4 Security mode
Usually HCS08 V6 MCUs are implemented with a secure operating mode. When in
secure mode, external access to internal memory is restricted, so that only instructions
fetched from secure memory can access secure memory.
The method by which the MCU is put into secure mode is not defined by the HCS08 V6
Core. The core receives an external input signal that, when asserted, informs to the core
that the MCU is in secure mode.
While in secure mode, the core controls the following set of conditions:
Chapter 10 Central processor unit
MC9S08PA4 Reference Manual, Rev. 5, 08/2017
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Summary of Contents for MC9S08PA4
Page 1: ...MC9S08PA4 Reference Manual Supports MC9S08PA4 Document Number MC9S08PA4RM Rev 5 08 2017 ...
Page 2: ...MC9S08PA4 Reference Manual Rev 5 08 2017 2 NXP Semiconductors ...
Page 22: ...MC9S08PA4 Reference Manual Rev 5 08 2017 22 NXP Semiconductors ...
Page 28: ...System clock distribution MC9S08PA4 Reference Manual Rev 5 08 2017 28 NXP Semiconductors ...
Page 150: ...Port data registers MC9S08PA4 Reference Manual Rev 5 08 2017 150 NXP Semiconductors ...
Page 196: ...Human machine interfaces HMI MC9S08PA4 Reference Manual Rev 5 08 2017 196 NXP Semiconductors ...
Page 224: ...Instruction Set Summary MC9S08PA4 Reference Manual Rev 5 08 2017 224 NXP Semiconductors ...
Page 232: ...Functional Description MC9S08PA4 Reference Manual Rev 5 08 2017 232 NXP Semiconductors ...
Page 258: ...FTM Interrupts MC9S08PA4 Reference Manual Rev 5 08 2017 258 NXP Semiconductors ...
Page 294: ...Functional description MC9S08PA4 Reference Manual Rev 5 08 2017 294 NXP Semiconductors ...
Page 398: ...Resets MC9S08PA4 Reference Manual Rev 5 08 2017 398 NXP Semiconductors ...
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