Hi, i want to know why while programming uP 8085, we start memory location with 2000h??
& why LXIH is used to save in HL pair, why not in other pair like BC??
& why LXIH is used to save in HL pair, why not in other pair like BC??
Its a very old processor,I dont remember much and also I didnt work with it much but I think the your main program starts from 2000H because above that memory location its the interrupt vectors.
Its a big story,you need to know many things before learning interrupts.In short Interrupts are events both hardware (external device called) and software (user called).Think it as a routine(assembly sub routine or function),which could be called any time during the normal execution of your code and when it is called it stop the normal execution of the user program and executes the interrupts function or code and when its done it return backs to the program execution from where it was called.Hi, please tell why above this memory are interrupt vectors, and what the use of it??
8085 is very old and as per me you should go for any other mcu.I started with PIC from Microchip but if you are looking something like 8085 go for 8051,8052,8053 arch.. from Atmel.Hi, i am talking about 8085 training kit, please tell how to study good programming of this old processor??
Its a big story,you need to know many things before learning interrupts.In short Interrupts are events both hardware (external device called) and software (user called).Think it as a routine(assembly sub routine or function),which could be called any time during the normal execution of your code and when it is called it stop the normal execution of the user program and executes the interrupts function or code and when its done it return backs to the program execution from where it was called.
Nonsense I dont think so,as per my post it has been said that the interrupt vector table (IVT) is located above 2000H which is in page 00H of 8085 ,I think its in a low memory region.Nonsense. The interrupt vectors for the 8085 are all in low memory and could be invoked by jamming an RST (RESTART(?)) instuction onto the databus. In addition to the RST 0 through RST 7 instuctions carried over from the 8080 there were three pins called RST7.5, RST6.5, and RST5.5 that when activated provided additional locations for interrupt service routines.
The reason for putting user code at an address like 0x2000 is that the board probably has either data or code in low memory that serves as a monitor or bootloader. CPM/2.2 used to load programs at 0x0100 reserving page 0 for system stuff.
This is a qualified guess. Due to the layout of the 8085 like reset vector at 0x0000h it was most practical to have the ROM. At the lower address range. Then some RAM at the higher addresses. It is the system designer who placed the RAM at address 0x2000. If your system is some sort of trainer. It will be very awkward to have user programs in the ROM. It will make programming a nightmare. I know as I have programmed embedded Z80 systems with EPROMS back in the days before flash. Therefor in your system the BIOS and other system related code is placed in the ROM starting from 0000. And the user RAM which can be used to entering user programs is placed at address 0x2000. Why the user RAM is placed at 0x2000 you must ask the system designer about. I have no idea.I have seen many PDF but i want to know exactly why memory starts from 2000H & why we interrupt the uP like trap,etc??
Those features can be used for a wide variety of tasks. In the simplest example I can think of imagine a program which has a list of task to perform. It moves from task to task on its list performing one after the other. When it gets to the end of the list it starts over again at the beginning.Hi, i have study some basic of it accumulator, registers,etc. but i want to go in deep in it.
i don't know why interrupt are used like Trap, intr 7.5,6.5,5, etc?? and time cyle how it work??
Hi, please put give some good practical examples for interrupt like all Trap,etc.Does that clear thing up for you a bit!!??
Hi, then please tell what the diffeence in registers pair BC,DE,HL & why we prefer to store memory or data contents in HL pairs??You have to learn to crawl before you can walk, and walk before you can run. From your postings I have a feeling that you are still on the crawl level then it comes to the 8085. So my advice to you is allow yourself to have a learning curve. Start simple and then you are confident take a step up. Interrupts are not that difficult. But it is reason for that interrupts always are one of last topics in most CPU courses. Trying to learn all at once will only confuse you
Which textbooks do they assign you at your school? What grade or college level is this? Do you not discuss anything with your classmates about assignments?
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