參數(shù)資料
型號: PIC14000T-20/SS
廠商: Microchip Technology
文件頁數(shù): 84/153頁
文件大小: 0K
描述: IC MCU OTP 4KX14 A/D 28SSOP
標準包裝: 2,100
系列: PIC® 14
核心處理器: PIC
芯體尺寸: 8-位
速度: 20MHz
連通性: I²C
外圍設備: POR,溫度傳感器,WDT
輸入/輸出數(shù): 20
程序存儲器容量: 7KB(4K x 14)
程序存儲器類型: OTP
RAM 容量: 192 x 8
電壓 - 電源 (Vcc/Vdd): 2.7 V ~ 6 V
數(shù)據(jù)轉換器: 斜率 A/D
振蕩器型: 內(nèi)部
工作溫度: 0°C ~ 70°C
封裝/外殼: 28-SSOP(0.209",5.30mm 寬)
包裝: 帶卷 (TR)
PIC14000
DS40122B-page 36
Preliminary
1996 Microchip Technology Inc.
5.4.2
SUCCESSIVE OPERATIONS ON I/O
PORTS
The actual write to an I/O port happens at the end of an
instruction cycle, whereas for reading, the data must be
valid at the beginning of the instruction cycle.
Therefore, care must be exercised if a write operation
is followed by a read operation on the same I/O port.
The sequence of instructions should be such to allow
the pin voltage to stabilize before the next instruction
which causes that port to be read into the CPU is
executed. Otherwise, the previous state of that pin may
be read into the CPU rather than the new state. When
in doubt, it is better to separate these instructions with
a NOP or another instruction not accessing this I/O
port.
FIGURE 5-13: SUCCESSIVE I/O OPERATION
Q1 | Q2 | Q3 | Q4
PC
PC + 2
PC + 1
PC + 3
MOVWF PORTC
Write to PORTC
MOVF PORTC, W
Read PORTC
NOP
RC<x>
Port pin sampled
here
Execute MOVWF
PORTC
Pin values
Execute MOVF
PORTC, W
Execute NOP
Example showing write to PORTC followed by immediate read. Some delays in settling may cause “old”
Port data to be read, especially at higher clock frequencies. Data setup time = (0.25 Tcyc- Tpd), where
Tcyc = instruction cycle time.
Q1 | Q2 | Q3 | Q4
Q1 | Q2 | Q3 | Q4 Q1 | Q2 | Q3 | Q4
相關PDF資料
PDF描述
MT5600SMI-X-L-34.R2 MODEM V.34 SERIAL DATA/FAX 3.3V
VE-22V-IY-S CONVERTER MOD DC/DC 5.8V 50W
VE-22T-IY-S CONVERTER MOD DC/DC 6.5V 50W
PIC14000T-20/SO IC MCU OTP 4KX14 A/D 28SOIC
MT100SEM-L.R1-SP DEVICE SERVER EMBEDDED 3.3V
相關代理商/技術參數(shù)
參數(shù)描述
PIC-1503 制造商:KODENSHI 制造商全稱:KODENSHI KOREA CORP. 功能描述:Photo IC(photodiode with signal processing)
PIC152N-A 制造商:SELEC CONTROLS 功能描述:PROCESS INDICATOR,2 ALARMS,1/8DIN,4DIGIT,RELAY OUTPUT
PIC152N-B-2 制造商:SELEC CONTROLS 功能描述:PROCESS INDICATOR,2 ALARMS,RETRANSMISSION OUTPUT
PIC163F73-I/SP 制造商:Microchip Technology Inc 功能描述:8BIT RISC - Bulk
PIC1655A-278 制造商:GI 功能描述: