參數(shù)資料
型號: MR80C52EXXX-20/883R
廠商: ATMEL CORP
元件分類: 微控制器/微處理器
英文描述: 8-BIT, MROM, 20 MHz, MICROCONTROLLER, CQCC44
封裝: LCC-44
文件頁數(shù): 66/109頁
文件大?。?/td> 10824K
代理商: MR80C52EXXX-20/883R
45
ATtiny20 [DATASHEET]
8235E–AVR–03/2013
Figure 10-3. Switching Between Input and Output in Break-Before-Make-Mode
10.2.4 Reading the Pin Value
Independent of the setting of Data Direction bit DDxn, the port pin can be read through the PINxn Register bit. As shown
in Figure 10-2 on page 43, the PINxn Register bit and the preceding latch constitute a synchronizer. This is needed to
avoid metastability if the physical pin changes value near the edge of the internal clock, but it also introduces a delay.
Figure 10-4 shows a timing diagram of the synchronization when reading an externally applied pin value. The maximum
and minimum propagation delays are denoted tpd,max and tpd,min respectively.
Figure 10-4. Synchronization when Reading an Externally Applied Pin value
Consider the clock period starting shortly after the first falling edge of the system clock. The latch is closed when the
clock is low, and goes transparent when the clock is high, as indicated by the shaded region of the “SYNC LATCH”
signal. The signal value is latched when the system clock goes low. It is clocked into the PINxn Register at the
succeeding positive clock edge. As indicated by the two arrows tpd,max and tpd,min, a single signal transition on the pin
will be delayed between and 1 system clock period depending upon the time of assertion.
out DDRx, r16
nop
0x02
0x01
SYSTEM CLK
INSTRUCTIONS
DDRx
intermediate tri-state cycle
out DDRx, r17
0x55
PORTx
0x01
intermediate tri-state cycle
Px0
Px1
tri-state
0x01
r17
0x02
r16
XXX
in r17, PINx
0x00
0xFF
INSTRUCTIONS
SYNC LATCH
PINxn
r17
XXX
SYSTEM CLK
t
pd, max
t pd, min
相關(guān)PDF資料
PDF描述
MR80C52EXXX-25SC 8-BIT, MROM, 25 MHz, MICROCONTROLLER, CQCC44
MR80C52TXXX-16/883:RD 8-BIT, MROM, 16 MHz, MICROCONTROLLER, CQCC44
MJ80C32U-25:D MICROCONTROLLER
MQ80C32E-36:RD 8-BIT, 36 MHz, MICROCONTROLLER, CQFP44
S80C32-40:R 8-BIT, 40 MHz, MICROCONTROLLER, PQCC44
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MR80C86 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:CMOS 16-Bit Microprocessor
MR80C86/B 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Harris Corporation 功能描述:Microprocessor, 16 Bit, 44 Pin, Ceramic, LCC
MR80C86-2 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:CMOS 16-Bit Microprocessor
MR80C86-2/883 制造商:Rochester Electronics LLC 功能描述:- Bulk
MR80C86-2/B 制造商:Intersil Corporation 功能描述:MPU 80C86 16BIT CMOS 8MHZ 44PLCC - Rail/Tube