参数资料
型号: ST72F651AR6T1
厂商: STMICROELECTRONICS
元件分类: 微控制器/微处理器
英文描述: 8-BIT, FLASH, MICROCONTROLLER, PQFP64
封装: 10 X 10 MM, ROHS COMPLIANT, TQFP-64
文件页数: 80/161页
文件大小: 2656K
代理商: ST72F651AR6T1
ST72651AR6
25/161
Doc ID 7215 Rev 4
CENTRAL PROCESSING UNIT (Cont’d)
Stack Pointer (SP)
Read/Write
Reset Value: 01 FFh
The Stack Pointer is a 16-bit register which is al-
ways pointing to the next free location in the stack.
It is then decremented after data has been pushed
onto the stack and incremented before data is
popped from the stack (see Figure 14).
Since the stack is 256 bytes deep, the 8 most sig-
nificant bits are forced by hardware. Following an
MCU Reset, or after a Reset Stack Pointer instruc-
tion (RSP), the Stack Pointer contains its reset val-
ue (the SP7 to SP0 bits are set) which is the stack
higher address.
The least significant byte of the Stack Pointer
(called S) can be directly accessed by a LD in-
struction.
Note: When the lower limit is exceeded, the Stack
Pointer wraps around to the stack upper limit, with-
out indicating the stack overflow. The previously
stored information is then overwritten and there-
fore lost. The stack also wraps in case of an under-
flow.
The stack is used to save the return address dur-
ing a subroutine call and the CPU context during
an interrupt. The user may also directly manipulate
the stack by means of the PUSH and POP instruc-
tions. In the case of an interrupt, the PCL is stored
at the first location pointed to by the SP. Then the
other registers are stored in the next locations as
shown in Figure 14.
– When an interrupt is received, the SP is decre-
mented and the context is pushed on the stack.
– On return from interrupt, the SP is incremented
and the context is popped from the stack.
A subroutine call occupies two locations and an in-
terrupt five locations in the stack area.
Figure 14. Stack Manipulation Example
15
8
00
01
70
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
PCH
PCL
SP
PCH
PCL
SP
PCL
PCH
X
A
CC
PCH
PCL
SP
PCL
PCH
X
A
CC
PCH
PCL
SP
PCL
PCH
X
A
CC
PCH
PCL
SP
Y
CALL
Subroutine
Interrupt
Event
PUSH Y
POP Y
IRET
RET
or RSP
@ 01FFh
@ 0100h
Stack Higher Address = 01FFh
Stack Lower Address = 0100h
1
相关PDF资料
PDF描述
ST72P60E2M1 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PDSO24
ST7260E2M1/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PDSO24
ST72T141K2M6XXX 8-BIT, OTPROM, 8 MHz, MICROCONTROLLER, PDSO34
ST72T141K2M3XXX 8-BIT, OTPROM, 8 MHz, MICROCONTROLLER, PDSO34
ST72T141K2MARE 8-BIT, OTPROM, 8 MHz, MICROCONTROLLER, PDSO34
相关代理商/技术参数
参数描述
ST72F651AR6T1E 功能描述:8位微控制器 -MCU Flash 32K USB/DTC/I2 RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
ST72P262M6/OZXTR 制造商:STMicroelectronics 功能描述:ST72P262M6/OZXTR
ST72P324TA/OBZTR 制造商:STMicroelectronics 功能描述:
ST72P324TA/OHXTR 制造商:STMicroelectronics 功能描述:
ST72P4T128M-A05AU 制造商:STEC Inc 功能描述:1GB,ECC,REG,DDR2-400,UNLEAD - Bulk