ARM ARM7TDMI Scheda Tecnica Scaricare il pdf (Pagina 41)

Programmer’s Model

ARM7TDMI Data Sheet

ARM DDI 0029E

3-15

Open Access

3.11 Reset

When the nRESET signal goes LOW, ARM7TDMI abandons the executing instruction

and then continues to fetch instructions from incrementing word addresses.

When nRESET goes HIGH again, ARM7TDMI:

1 Overwrites R14_svc and SPSR_svc by copying the current values of the PC

and CPSR into them. The value of the saved PC and SPSR is not deﬁned.

2 Forces M[4:0] to 10011 (Supervisor mode), sets the I and F bits in the CPSR,

and clears the CPSR’s T bit.

3 Forces the PC to fetch the next instruction from address 0x00.

4 Execution resumes in ARM state.

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ARM ARM7TDMI Scheda Tecnica Pagina 41