參數(shù)資料
型號(hào)： PIC16F819
廠商： Microchip Technology Inc.
英文描述： 18/20-Pin Enhanced FLASH Microcontrollers with nanoWatt Technology(18/20引腳，納瓦技術(shù)增強(qiáng)FLASH微控制器)
中文描述： 18/20-Pin增強(qiáng)型閃存微控制器采用納瓦技術(shù)（18/20引腳，納瓦技術(shù)增強(qiáng)閃存微控制器）
文件頁數(shù)： 25/164頁
文件大?。?/td> 3045K
代理商： PIC16F819
2002 Microchip Technology Inc.
Preliminary
DS39598C-page 23
PIC16F818/819
2.3
PCL and PCLATH
The program counter (PC) is 13 bits wide. The low byte
comes from the PCL register, which is a readable and
writable register. The upper bits (PC<12:8>) are not
readable, but are indirectly writable through the
PCLATH register. On any RESET, the upper bits of the
PC will be cleared. Figure 2-5 shows the two situations
for the loading of the PC. The upper example in the fig-
ure shows how the PC is loaded on a write to PCL
(PCLATH<4:0>
→
PCH). The lower example in the fig-
ure shows how the PC is loaded during a
CALL
or
GOTO
instruction (PCLATH<4:3>
→
PCH).
FIGURE 2-5:
LOADING OF PC IN
DIFFERENT SITUATIONS
2.3.1
COMPUTED GOTO
A computed
GOTO
is accomplished by adding an offset
to the program counter (
ADDWF PCL
). When doing a
table read using a computed
GOTO
method, care
should be exercised if the table location crosses a PCL
memory boundary (each 256-byte block). Refer to the
application note,
“Implementing a Table Read”
(AN556).
2.3.2
STACK
The PIC16F818/819 family has an 8-level deep x 13-bit
wide hardware stack. The stack space is not part of
either program or data space and the stack pointer is not
readable or writable. The PC is PUSHed onto the stack
when a
CALL
instruction is executed, or an interrupt
causes a branch. The stack is POPed in the event of a
RETURN, RETLW
or a
RETFIE
instruction execution.
PCLATH is not affected by a PUSH or POP operation.
The stack operates as a circular buffer. This means that
after the stack has been PUSHed eight times, the ninth
push overwrites the value that was stored from the first
push. The tenth push overwrites the second push (and
so on).
2.4
Indirect Addressing: INDF and
FSR Registers
The INDF register is not a physical register. Addressing
INDF actually addresses the register whose address is
contained in the FSR register (FSR is a
pointer
). This is
indirect addressing.
EXAMPLE 2-1:
INDIRECT ADDRESSING
Reading INDF itself indirectly (FSR = 0) will produce
00h. Writing to the INDF register indirectly results in a
no operation (although STATUS bits may be affected).
A simple program to clear RAM locations 20h-2Fh
using indirect addressing is shown in Example 2-2.
EXAMPLE 2-2:
HOW TO CLEAR RAM
USING INDIRECT
ADDRESSING
An effective 9-bit address is obtained by concatenating
the 8-bit FSR register and the IRP bit (STATUS<7>), as
shown in Figure 2-6.
PC
12
8
7
0
5
PCLATH<4:0>
PCLATH
Instruction with
PCL as
Destination
ALU
GOTO,CALL
Opcode <10:0>
8
PC
12
11 10
0
11
PCLATH<4:3>
PCH
PCL
8
7
2
PCLATH
PCH
PCL
Note 1:
There are no status bits to indicate stack
overflow or stack underflow conditions.
2:
There are no instructions/mnemonics
called PUSH or POP. These are actions
that occur from the execution of the
CALL, RETURN, RETLW
and
RETFIE
instructions, or the vectoring to an
interrupt address.
Register file 05 contains the value 10h
Register file 06 contains the value 0Ah
Load the value 05 into the FSR register
A read of the INDF register will return the value
of 10h
Increment the value of the FSR register by one
(FSR = 06)
A read of the INDF register now will return the
value of 0Ah
movlw
movwf
clrf
incf
btfss
goto
0x20
FSR
INDF
FSR
FSR,4
NEXT
;initialize pointer
;to RAM
;clear INDF register
;inc pointer
;all done
;NO, clear next
NEXT
CONTINUE
:
;YES, continue
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PIC16F819-E/ML 功能描述:8位微控制器 -MCU 3.5KB 256 RAM 16 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
PIC16F819-E/P 功能描述:8位微控制器 -MCU 3.5KB 256 RAM 16 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
PIC16F819-E/SO 功能描述:8位微控制器 -MCU 3.5KB 256 RAM 16 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
PIC16F819-E/SS 功能描述:8位微控制器 -MCU 3.5KB 256 RAM 16 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
PIC16F819-E/SSVAO 制造商:Microchip Technology Inc 功能描述:
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