M37632EFFP#U2 Renesas Electronics America, M37632EFFP#U2 Datasheet - Page 117

• Manufacturer Part Number: M37632EFFP#U2
• Description: IC 740 MCU 80QFP
• Manufacturer: Renesas Electronics America

Specifications of M37632EFFP#U2

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

4.4 Notes on programming
Fig. 4.4.1 Initialization of flags in Processor Status Register
Rev.2.00 Nov 14, 2006
REJ09B0322-0200
Fig. 4.4.2 PLP instruction execution sequence
4.4.1 Processor Status Register
(1) Initialization of Processor Status Register
(2) How to reference Processor Status Register
Flags which affect program execution must be initialized after a reset. In particular, it is essential
to initialize the T and D flags because they have an important effect on calculations.
After a reset, the contents of processor status register (PS) are undefined except for the I flag
which is “1.”
To reference the contents of the processor status register (PS), execute the PHP instruction
once then read the contents of (S + 1). If necessary, execute the PLP instruction to
return the PS to its original status.
A NOP instruction should be executed after every PLP instruction.
Reason
NOP instruction
PLP instruction
page 109 of 185
Flags initializing
Main program
Reset
Fig. 4.4.3 Stack memory contents after PHP
(S) + 1
(S)
instruction execution
NOTES ON USE
Saved PS