參數(shù)資料
型號: DS87C520
英文描述: EPROM/ROM High-Speed Micro
中文描述: EPROM/ROM高速微控制器
文件頁數(shù): 21/45頁
文件大?。?/td> 1415K
代理商: DS87C520
DS87C520/DS83C520 EPROM/ROM High-Speed Microcontrollers
21 of 45
how the operation would compare when using the ring, and when starting up normally. The default state
is to exit Stop mode without using the ring oscillator.
The RGSL - Ring Select bit at EXIF.1 (EXIF; 91h) controls this function. When RGSL = 1, the CPU will
use the ring oscillator to exit Stop mode quickly. As mentioned above, the processor will automatically
switch from the ring to the crystal after a delay of 65,536 crystal clocks. For a 3.57MHz crystal, this is
approximately 18ms. The processor sets a flag called RGMD-Ring Mode, located at EXIF.2, that tells
software that the ring is being used. The bit will be a logic 1 when the ring is in use. Attempt no serial
communication or precision timing while this bit is set, since the operating frequency is not precise.
Figure 4. Ring Oscillator Exit from Stop Mode
EMI REDUCTION
One of the major contributors to radiated noise in an 8051-based system is the toggling of ALE. The
microcontroller allows software to disable ALE when not used by setting the ALEOFF (PMR.2) bit to 1.
When ALEOFF = 1, ALE will still toggle during an off-chip MOVX. However, ALE will remain in a
static mode when performing on-chip memory access. The default state of ALEOFF = 0 so ALE toggles
at a frequency of XTAL/4.
STOP MODE WITH RING STARTUP
STOP MODE WITHOUT RING STARTUP
NOTE:
DIAGRAM ASSUMES THAT THE OPERATION FOLLOWING STOP REQUIRES
LESS THAN 18ms TO COMPLETE.
相關(guān)PDF資料
PDF描述
DS87C520-ECL EPROM/ROM High-Speed Micro
DS87C520-ENL EPROM/ROM High-Speed Micro
DS87C520-MCL EPROM/ROM High-Speed Micro
DS87C520-MNL EPROM/ROM High-Speed Micro
DS87C520-QCL EPROM/ROM High-Speed Micro
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS87C520_1 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:EPROM/ROM High-Speed Micro
DS87C520+ECL 制造商:Maxim Integrated Products 功能描述:MICRO OTP HI SPD 44TQFP 33MHZ PB-FR - Trays
DS87C520+MCL 制造商:Maxim Integrated Products 功能描述:MICRO OTP HI SPD 40PDIP 33MHZ PB-FR - Rail/Tube 制造商:Maxim Integrated Products 功能描述:IC 8BIT CPU CMOS 87C520 DIP40
DS87C520+MNL 制造商:Maxim Integrated Products 功能描述:MICRO HI SPD 40PDIP 33MHZ IND PB-FR - Rail/Tube
DS87C520+QCL 制造商:Maxim Integrated Products 功能描述:MCU 8BIT CISC 16KB EPROM 5V 44PLCC - Rail/Tube