Datasheet

V850ES/JG3 CHAPTER 28 ON-CHIP DEBUG FUNCTION
R01UH0015EJ0300 Rev.3.00 Page 756 of 870
Sep 30, 2010
(3) Reset vector
A reset vector includes the jump instruction for the debug monitor program.
[How to secure areas]
It is not necessary to secure this area intentionally. When downloading a program, however, the debugger rewrites
the reset vector in accordance with the following cases. If the rewritten pattern does not match the following cases,
the debugger generates an error (F0C34 when using the ID850QB).
(a) When two nop instructions are placed in succession from address 0
Before rewriting After rewriting
0x0 nop → Jumps to debug monitor program at 0x0
0x2 nop 0x4 xxxx
0x4 xxxx
(b) When two 0xFFFF are successively placed from address 0 (already erased device)
Before rewriting After rewriting
0x0 0xFFFF → Jumps to debug monitor program at 0x0
0x2 0xFFFF 0x4 xxxx
0x4 xxxx
(c) The jr instruction is placed at address 0 (when using CA850)
Before rewriting After rewriting
0x0 jr disp22 → Jumps to debug monitor program at 0x0
0x4 jr disp22 - 4
(d) mov32 and jmp are placed in succession from address 0 (when using IAR compiler ICCV850)
Before rewriting After rewriting
0x0 mov imm32,reg1 → Jumps to debug monitor program at 0x0
0x6 jmp [reg1] 0x4 mov imm32,reg1
0xa jmp [reg1]
(e) The jump instruction for the debug monitor program is placed at address 0
Before rewriting After rewriting
Jumps to debug monitor program at 0x0 → No change