lots of words

README.md

@@ -1,5 +1,45 @@
 # 6502-hacking
 
-> HACKING <
+A project to work with [Ben Eater's 6502] computer kit, replacing the clock module
+and EEPROM, amongst other things.
 
+\> HACKING <
 
+This is very much work in progress but does manage to demonstrate several things.
+It's made up of two parts. `6502-contoller` is an Arduino firmware for interacting
+with the 6502 and `6502-loader` is a python script to interact with the Arduino.
+
+## 6502-contoller
+This Arduino firmware started off fairly similarly to Ben's monitor firmware but I
+needed a couple additional things. As I didn't have the clock module it also provided
+a clock signal from the start. It can also be tied to the 6502 `RSTb` line and control
+the reset signal. I also opted to not buy the EEPROM reader for several reasons.
+One, I don't have the money and additionally I just hate the idea of having
+to pull a chip to program it, place it back in, blah, blah. I spend 20 years in web
+development damn it! CTRL-R is my compiler! So the firmware can load the entire ROM
+into memory, read the `ADDRESS` lines coming off the 6502 and provided the addressed byte
+on the `DATA` lines.
+
+This second feature, while being generally great and speeding up development does have
+one major hiccup. It's requires not only an Arduino with many IO, like a Mega, it
+also requires a device with over about 60kb of memory... unlike a Mega. For this project
+I'm using an inexpressive STMicro Nucleo F401RE devboard. While inexpressive these
+are still not as accessible as a Mega for some people. The originally I had wanted to
+request each byte over serial as the address lines change but could not manage to make
+this work. Now that the entire project is working better and my understanding has
+improved I *do* think it's possible and might be worth revisiting.
+
+## 6502-loader.py
+This part interacts with the Arduino firmware. In it's basic flow it handles several things.
+
+* Stopping the clock
+* Putting the 6502 into reset
+* Loading the ROM into the Arduinos memory
+* Restarting the clock
+* Bringing the 6502 out of reset
+* Runs monitor mode
+
+At this point the script can be exited and the 6502 will continue to run. A normal terminal
+can be opened to stop the clock and use single stepping from the devboard.
+
+[Ben Eater's 6502]: https://eater.net/6502