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参数资料
型号： PIC18LF6720T-I/PT
厂商： Microchip Technology
文件页数： 105/165页
文件大小： 0K
描述： IC MCU FLASH 64KX16 LV 64-TQFP
产品培训模块： Asynchronous Stimulus
标准包装： 1,200
系列： PIC® 18F
核心处理器： PIC
芯体尺寸： 8-位
速度： 25MHz
连通性： I²C，SPI，UART/USART
外围设备： 欠压检测/复位，LVD，POR，PWM，WDT
输入/输出数： 52
程序存储器容量： 128KB（64K x 16）
程序存储器类型： 闪存
EEPROM 大小： 1K x 8
RAM 容量： 3.75K x 8
电压 - 电源 (Vcc/Vdd)： 2 V ~ 5.5 V
数据转换器： A/D 12x10b
振荡器型： 外部
工作温度： -40°C ~ 85°C
封装/外壳： 64-TQFP
包装： 带卷 (TR)
PIC18F6520/8520/6620/8620/6720/8720
DS39609B-page 42
2004 Microchip Technology Inc.
4.2
Return Address Stack
The return address stack allows any combination of up
to 31 program calls and interrupts to occur. The PC
(Program Counter) is pushed onto the stack when a
CALL
or RCALL instruction is executed, or an interrupt
is Acknowledged. The PC value is pulled off the stack
on a RETURN, RETLW or a RETFIE instruction. PCLATU
and PCLATH are not affected by any of the RETURN or
CALL
instructions.
The stack operates as a 31-word by 21-bit RAM and a
5-bit stack pointer, with the stack pointer initialized to
00000b after all Resets. There is no RAM associated
with stack pointer 00000b. This is only a Reset value.
During a CALL type instruction, causing a push onto the
stack, the stack pointer is first incremented and the
RAM location pointed to by the stack pointer is written
with the contents of the PC. During a RETURN type
instruction, causing a pop from the stack, the contents
of the RAM location pointed to by the STKPTR are
transferred to the PC and then the stack pointer is
decremented.
The stack space is not part of either program or data
space. The stack pointer is readable and writable and
the address on the top of the stack is readable and writ-
able through SFR registers. Data can also be pushed
to, or popped from the stack using the top-of-stack
SFRs. Status bits indicate if the stack pointer is at, or
beyond the 31 levels provided.
4.2.1
TOP-OF-STACK ACCESS
The top of the stack is readable and writable. Three
register locations, TOSU, TOSH and TOSL, hold the
contents of the stack location pointed to by the
STKPTR register. This allows users to implement a
software stack if necessary. After a CALL, RCALL or
interrupt, the software can read the pushed value by
reading the TOSU, TOSH and TOSL registers. These
values can be placed on a user defined software stack.
At return time, the software can replace the TOSU,
TOSH and TOSL and do a return.
The user must disable the global interrupt enable bits
during
this
time
to
prevent
inadvertent
stack
operations.
4.2.2
RETURN STACK POINTER
(STKPTR)
The STKPTR register contains the stack pointer value,
the STKFUL (Stack Full) status bit and the STKUNF
(Stack Underflow) status bits. Register 4-2 shows the
STKPTR register. The value of the stack pointer can be
0 through 31. The stack pointer increments when val-
ues are pushed onto the stack and decrements when
values are popped off the stack. At Reset, the stack
pointer value will be ‘0’. The user may read and write
the stack pointer value. This feature can be used by a
Real-Time
Operating
System
for
return
stack
maintenance.
After the PC is pushed onto the stack 31 times (without
popping any values off the stack), the STKFUL bit is
set. The STKFUL bit can only be cleared in software or
by a POR.
The action that takes place when the stack becomes
full, depends on the state of the STVREN (Stack Over-
flow
Reset
Enable)
configuration
bit.
Refer
to
Section 24.0 “Instruction Set Summary” for a
description of the device configuration bits. If STVREN
is set (default), the 31st push will push the (PC + 2)
value onto the stack, set the STKFUL bit and reset the
device. The STKFUL bit will remain set and the stack
pointer will be set to ‘0’.
If STVREN is cleared, the STKFUL bit will be set on the
31st push and the stack pointer will increment to 31.
Any additional pushes will not overwrite the 31st push
and STKPTR will remain at 31.
When the stack has been popped enough times to
unload the stack, the next pop will return a value of zero
to the PC and sets the STKUNF bit, while the stack
pointer remains at ‘0’. The STKUNF bit will remain set
until cleared in software or a POR occurs.
Note:
Returning a value of zero to the PC on an
underflow has the effect of vectoring the
program to the Reset vector, where the
stack conditions can be verified and
appropriate actions can be taken.
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相关代理商/技术参数
参数描述
PIC18LF6721-I/PT 功能描述:8位微控制器 -MCU 128kBF 4096RM 40MHz nonoWatt 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
PIC18LF6721T-I/PT 功能描述:8位微控制器 -MCU 128kBF 4096RM 40MHz nonoWatt 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
PIC18LF6722-I/PT 功能描述:8位微控制器 -MCU 128 KB FL 4K RAM 70 I/O 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
PIC18LF6722-I/PT 制造商:Microchip Technology Inc 功能描述:8-Bit Microcontroller IC
PIC18LF6722T-I/PT 功能描述:8位微控制器 -MCU 128 KB FL 4K RAM 70 I/O 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
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