The 8085 microprocessor doesn’t have any built-in memory. Thus, to use it in any significant project we need to interface external memory chips to it. This is a complete guide on how you would go about doing that. There’s an example problem to help you get a more application-based explanation too.
A good embedded systems developer is expected to be in tune with the effect their code is having on the internal circuitry of the device they are programming. This skill develops over time and helps you optimize your code for efficiency and quickly debug it in the event of some nasty bugs. Here’s one of the concepts that zeros in on how instructions execute on a micro-level. Learning how timing diagrams work will come in handy as we progress to much more complex topics like instruction parallelism, multi-threading, and RTOS.
Now that we are familiar with the working of the 8255, let’s interface it with the 8085.
The 8255 is/was a very common IC primarily used to increase the number of I/O pins that a microprocessor could address. However, the 8255 is extremely powerful and does a lot more than simple I/O data transfers. Here’s a simplified and in-depth explanation of the 8255 programmable peripheral interface. This is your one stop guide to completely understand its working.
The buses of any processor are the network through which all communication inside an embedded system is done. Both, internal as well as external. Without the buses, it’s like having a Ferrari with no wheels. The bus structure of a processor can tell you a lot about its design and how it can be interfaced with the outside world. For the 8085, we have a few unique processes that we need to run to use its buses. First, we will understand the role of all the buses, and then we will understand the processes that need to be done to use them. Though these processes might seem convoluted right now, rest assured, it has all been done in the interest of optimizing the processor for best usage.
All processors and controllers can access data stored in the memory using instructions or commands. However, the method in which they access this data varies on the addressing modes that they are capable of using. So, in short, data access has many types, known as addressing modes. Let’s take a look at the addressing modes available in 8085.
Interfacing I/O devices with a processor is an integral part of any embedded system. With the 8085, there are two methods to interface I/O devices; I/O mapped I/O and memory-mapped I/O. Both of these methods have their perks and snags. This is an important concept. So pay attention and understand the difference between the two methods. We’ll revisit this in the ARM Cortex M course.
A microprocessor deals with a lot of data passing through it. However, not all recipients and senders of this data are alike. They might have many differences in terms of how they send or receive data. Hence, we need different data transfer mechanisms. Let’s take a look at all the different ways in which the 8085 transfers data between peripherals and itself.
The third category of the instruction set is the bunch of instructions that are responsible for implementing logic and helping the ALU perform logical operations.
We begin our foray into the instruction set of the 8085 microprocessor with the data transfer instructions. These instructions, as their classification suggests, are used to move around data within, from, or into the microprocessor.
Next up, we’ll take a look at the arithmetic instructions available to us in 8085. Keep an eye out for the subtraction instructions. The 2’s complement aspect can make them seem confusing at first.
This 8085 quiz has been crafted to test skills in a wide range of concepts that we have covered in this free course. Competitive exam takers will find the detailed solutions helpful. Clearing this quiz will unlock the final certification test. For detailed performance analysis, please ensure that you are logged in before attempting the quiz.
Almost every modern processor has a system to handle interrupts. Let’s take an in-depth look at the entire process of how interrupts work in the 8085 processor. Interrupts classification, their types, and internal circuitry.
The architecture of any processor is the key to understanding everything about it. Its purpose, its capacity, and power, everything can be understood from a peek at the innards of the chip. Studying the 8085’s internal architecture will set you up towards understanding any processor in a jiffy.
The stack is an important data structure in embedded systems as it allows us to increase our code efficiency by implementing subroutines. Let’s study everything we need to know to start using them.
The 8085 has 40 pins. Understanding the function of each pin will give you a brief idea about the capabilities of the microprocessor.
An age-old question broken down into a simple conceptual explanation. The difference between microcontrollers and microprocessors is easy to remember with this explanation.
