41
CHAPTER 2 CPU
2.7.3
Processor Status (PS)
The PS register consists of the bits controlling the CPU Operation and the bits
indicating the CPU status.
■
Processor Status (PS)
As shown in Figure 2.7-6, the high-order byte of the PS register consists of a register bank pointer (RP) and
an interrupt level mask register (ILM). The RP indicates the start address of a register bank. The low-order
byte of the PS register is a condition code register (CCR), containing the flags to be set or reset depending
on the results of instruction execution or interrupt occurrences.
Figure 2.7-6 Processor Status (PS) Structure
■
Condition Code Register (CCR)
Figure 2.7-7 is a diagram of condition code register configuration.
Figure 2.7-7 Condition Code Register (CCR) Configuration
●
I: Interrupt enable flag:
Interrupts other than software interrupts are enabled when the I flag is "1" and are masked when the I flag is
"0". The I flag is cleared by a reset.
●
S: Stack flag:
When the S flag is "0", USP is enabled as the stack manipulation pointer.
When the S flag is "1", SSP is enabled as the stack manipulation pointer.
The S flag is set by an interrupt reception or a reset.
ILM
RP
CCR
PS
15
13 12
8
7
bit
0
7
6
5
4
3
2
1
0
bit
-
I
S
T
N
Z
V
C
CCR
-
0
1
*
*
*
*
*
Initial value
*: Undefined
Содержание MB90390 Series
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Страница 17: ...xiii APPENDIX D List of Interrupt Vectors 690 INDEX 695 ...
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Страница 132: ...104 CHAPTER 5 CLOCKS ...
Страница 152: ...124 CHAPTER 6 CLOCK MODULATOR ...
Страница 210: ...182 CHAPTER 11 TIME BASE TIMER ...
Страница 218: ...190 CHAPTER 12 WATCHDOG TIMER ...
Страница 264: ...236 CHAPTER 14 16 BIT RELOAD TIMER WITH EVENT COUNT FUNCTION ...
Страница 274: ...246 CHAPTER 15 WATCH TIMER ...
Страница 306: ...278 CHAPTER 17 DTP EXTERNAL INTERRUPTS ...
Страница 338: ...310 CHAPTER 18 8 10 BIT A D CONVERTER ...
Страница 364: ...336 CHAPTER 19 UART0 UART1 ...
Страница 398: ...370 CHAPTER 20 UART2 UART3 Figure 20 5 2 ORE Set Timing Receive data RDRF ORE ...
Страница 432: ...404 CHAPTER 20 UART2 UART3 ...
Страница 482: ...454 CHAPTER 22 SERIAL I O ...
Страница 560: ...532 CHAPTER 24 STEPPING MOTOR CONTROLLER ...
Страница 582: ...554 CHAPTER 27 ROM MIRRORING MODULE ...
Страница 632: ...604 CHAPTER 29 EXAMPLES OF SERIAL PROGRAMMING CONNECTION ...
Страница 722: ...694 APPENDIX ...
Страница 723: ...695 INDEX The index follows on the next page This is listed in alphabetic order ...
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