Epson S5U1C63000A - Manual (Page 165)

CHAPTER 8: DEBUGGER
S5U1C63000A MANUAL EPSON 151
(S1C63 FAMILY ASSEMBLER PACKAGE)
Map break and illegal instruction break
The program also breaks when one of the following errors is encountered during program execution:
(1) Access to undefined program area
A break occurs when an undefined area of the program memory map is accessed.
(2) Access to undefined data area
A break occurs when an undefined area of the data memory map is accessed.
(3) Write to data ROM area
A break occurs when a write to the data ROM area is attempted.
Notes: • If the return address is popped from the stack by a ret or reti instruction in an area with prohib-
ited 16-bit access, invalid data is read out from a 16-bit data bus that does not have any memory
connected. In the ICE, because the bus is pulled up, 0xffff is read out, causing control to
return to that address. This could result in generating a map break.
• A break caused by an undefined program area access occurs before execution of such opera-
tion. On the other hand, a map break caused by access to an undefined data area or a write to
the data ROM area occurs one or two instructions after execution of such operation.
• In user breaks based on command settings also, a PC break and sequential break occur before
execution of operation. However, other breaks such as a data break, register break, and stack
break occur one or two instructions after execution of operation.