In this first video of the series I:

• set my goals for the series and talk about what I am going to do

• describe the 8088/8086 and show the differences between the two

• put the 8088 on a breadboard and start connecting all relevant pins explaining all the input and output signals of the CPU

• build a simple contraption to drive the CLOCK and RESET signals

• talk about 8086 address space and how it addresses the memory

• explain how the processor starts executing machine code after reset

• connect LEDs to all data/address and control pins to visualise their states

• start the CPU and analyse its behaviour step by step after reset

In this video you can see how I:

• add latches to store the address signals from the multiplexed data/address pins

• connect resistors to drive the data bus and simulate the NOP (no-operation) machine code for the CPU to fetch and execute while clock signal step by step

• add the proper flash memory and with a simple programme

• talk about 8086 registers and how it divides the 1MB memory space into 64kB segments

• explain in details the test programme in the flash memory

• run the programme on our breadboard computer and visualise the CPUs address and data buses on the LEDs

• allow the programme to show its calculations on the data bus LEDs

In this video I:

• talk about the memory map of our computer

• build an address decoder using logic gates, to activate two different memory chips depending on the address the CPU wishes to access

• add a RAM memory chip and connect both memories to the address decoder

• talk about interrupts in 8086 and explain the Interrupt Vector Table at the bottom of the RAM

• introduce the Programmable Interrupt Controller (8259) and its role in interrupt handling

• explain the concept of the processor's stack and its importance in the context of interrupt handling

• go into details of the programme used to initialise the processor and the handler of the Non-Maskable Interrupt

• raise the MNI interrupt (using a wire) and analyse the CPUs behaviour in details

In this video you can join me to see how I:

• add a new chip (74244) with 8 buffers to simulate the PIC's response to the interrupt request (without actually using the 8259)

• write a new programme with a new interrupt handler for the INTR (maskable) requests

• raise an interrupt using a wire on the INTR pin and, like previously, analyse the CPUs behaviour step by step

• add an I/O address decoder using 74138 chip which allows us to connect 8 different I/O devices

• add a Text LCD as our first device in the I/O address space, including logic required to access it from the CPU

• programme a set of functions to talk to the LCD and test it by running the computer step by step

• replace the manual clock with the proper crystal square wave generator using the Intel 8284 chip

• test the whole computer and the LCD again - this time by using high frequency clock generator

This video is exclusively devoted to programming our breadboard computer and the theory behind it. You can see how I:

• tidy up the last programme for the Text LCD testing

• explain calling conventions allowing to mix code from different languages

• talk about differences between functions compiled in different languages

• how to write functions in assembler, which can be called from C and which can call other C functions properly

• write functions both in assembler and C to support the Text LCD

• create a function to display values of all Intel 8086 registers on the LCD

• explain the breakpoint interrupt (INT 3)

• write the breakpoint handler to collect the full state of all CPU's registers and call the function to display them written in C

• discuss in details the FLAGS register of the 8086

• show how to switch the 8086 into the single-step mode

• write the single-step interrupt handler (INT 1) and display the registers' states on the LCD

In this video I add more peripherals and programme them. Here is what happens step by step:

• reactivate the 74244 octal buffers to act as a read-only register reflecting the states of the new push buttons

• add functions to read the button states to allow single-step full functionality

• add the PIC 8259 - Programmable Interrupt Controller

• initialise the PIC and test by raising an interrupt manually while single-stepping

• add the programmable timers - the 8254

• set-up the timer to raise a regular system tick interrupt 100 times a second

• test the whole thing

• talk a little bit more about flags in the FLAGS register

In this video I build a new computer using 80188 processor. This is what you will see in this video:

• 80188 introduction. Differences between multiple versions

• peripherals in the 80188

• similarities and differences of the pins in both 8088 and 80188

• changes required in software to handle the built-in peripherals

• testing the new computer

• both computers running the same programme side by side

In this video I design a PCB for the 80188 computer from the last video and add programmable I/O ports - the 8255. This is what you will see:

• the design of the PCB for my 80188 computer

• discussion about using the timers in the 80188

• testing new computer soldered on the PCB with the text LCD

• introduction of the programmable I/O ports: the 8255

• testing the 8255 using the LCD connected via its I/O pins