C166: Purpose of START167.A66

Information in this article applies to:

• C166 All Versions

QUESTION

What is the purpose of the START167.A66 file? It seems to configure the memory arrangements of the device. If that is the case, when is it executed?

ANSWER

START167.A66 contains the startup code for the C167 derivative devices. It executes immediately upon reset of the device and optionally performs the following operations in order:

• Initializes the SYSCON SFR registers (and BUSCON0 for the C167).
• Initializes the ADDRSELx and BUSCONx SFR registers to configure memory access.
• Reserves and initializes the hardware stack and the stack underflow and overflow registers.
• Sets up DPP0 to DPP3 and CP for memory and registerbank access.
• Reserves and initializes the user stack area and the user stack pointer (R0).
• Clears data memory.
• Initializes variables that were explicitly initialized.
• Calls the main function.

If you are using the monitor, then the monitor contains it's own startup code that performs most of these operations. Once it has been completed, the startup code in your own application has no effect on the configuration of the device.

MORE INFORMATION

• Refer to START167.A66 in the C166 User's Guide.

SEE ALSO

• C166: Start 167 and Boot 167

Last Reviewed: Thursday, February 25, 2021