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George Foot
United Kingdom
เข้าร่วมเมื่อ 26 พ.ย. 2009
Hobbyist electronics experiments, building homebrew computers based on 80s technology, and other things like that!
Debugging and Profiling 6502-based Computers
I wanted to demonstrate the process of debugging software and hardware faults in homebrew 6502 computer systems, using a cheap logic analyzer and the excellent 6502 Decoder software.
The logic analyzer is Cypress EZ-USB FX2LP. The fx2pipe and decoder software is here: github.com/hoglet67/6502Decoder
00:00 Intro
00:33 Example code to debug
02:38 Monitoring the circuit
03:38 Cypress EZ-USB FX2LP
06:24 Capturing data
08:00 Manual inspection
09:48 The 6502 Decoder
13:21 Diagnosing a software bug
15:07 Deeper investigations
17:11 Diagnosing hardware bugs
20:37 Faster clock speeds
24:49 Profiling your code
27:17 Conclusion
The logic analyzer is Cypress EZ-USB FX2LP. The fx2pipe and decoder software is here: github.com/hoglet67/6502Decoder
00:00 Intro
00:33 Example code to debug
02:38 Monitoring the circuit
03:38 Cypress EZ-USB FX2LP
06:24 Capturing data
08:00 Manual inspection
09:48 The 6502 Decoder
13:21 Diagnosing a software bug
15:07 Deeper investigations
17:11 Diagnosing hardware bugs
20:37 Faster clock speeds
24:49 Profiling your code
27:17 Conclusion
มุมมอง: 1 799
วีดีโอ
Demos and Tests of my Fast 6502 System
มุมมอง 3Kปีที่แล้ว
Here's a tour through some demos and test of my 6502-based system. The demos were intended to showcase its speed, but the flaw in that plan was not really being able to compare that against anything! Some of the demo code is available on github: Life - github.com/gfoot/life6502 Mandelbrot - github.com/gfoot/mandelbrot6502 Prime Sieve - github.com/gfoot/primesieve6502 00:00 Introduction 00:24 Li...
Fast PDIP 6502 computer explained
มุมมอง 3.1Kปีที่แล้ว
Talking through the ideas behind my Fast PDIP 6502 Computer that currently runs at clock speeds up to 35MHz, including how the Clock Stretching circuit works. Hackaday.io page with schematics and more details: hackaday.io/project/192630-fast-pdip-6502-computer 6502.org forum thread with design discussion: forum.6502.org/viewtopic.php?f=4&t=7670 00:00 Intro 02:04 Typical 6502 architecture 03:21 ...
Using KiCad to design Breadboard Layouts
มุมมอง 3.3Kปีที่แล้ว
A brief introduction to how I sometimes use KiCad's PCB layout tools to help with solderless breadboard layout planning. This is a great way to find a tidy layout, and ensure the thing you're building actually matches your schematic! (This segment was cut from another video as it's a bit of a digression, but I think makes sense standing on its own.)
Low Tech Serial Input with 6502
มุมมอง 818ปีที่แล้ว
Let's extend the serial transmit circuit by adding a receive circuit, so we can also receive data from the PC! 00:00 Intro 02:04 Design overview 07:11 Detailed tour of schematic 20:30 Schematic errata 23:41 Writing test code 32:19 Code errata 33:34 Practical test 36:26 Outro
Serial output circuit connected to 6502 computer
มุมมอง 1.2Kปีที่แล้ว
Let's take the low tech serial output circuit from my last video and hook it up to a new 6502 computer! Links to design of new computer: hackaday.io/project/192630-fast-pdip-6502-computer forum.6502.org/viewtopic.php?f=4&t=7670
Low Tech Serial Output
มุมมอง 3K2 ปีที่แล้ว
Let's implement a low-tech TTL serial output circuit, to provide a simple and reliable debug output port for the homebrew 6502 computer. This avoids dependencies on complex circuits and ACIAs that require configuration, so that the CPU will be able to output debug data with just a couple of lines of code. If you're interested in Debug Innovations' TTL VGA Terminal, you can get schematics, gerbe...
800x600 SVGA Upgrade for 6502 Breadboard Computer
มุมมอง 4.2K2 ปีที่แล้ว
Upgrading from 640x480 to 800x600 should be just a change in clock frequnecy and timings - but it opened a real can of worms! Code here, in the 800x600 branch: github.com/gfoot/simplevga6502/tree/800x600 00:00 Intro 01:44 Hardware changes 02:51 Software changes 04:36 Stability issues 07:10 Conclusion
Loading Data from a Floppy Disk on a 6502
มุมมอง 2.9K2 ปีที่แล้ว
After last week's hardware upgrades, the Floppy Disk Controller circuit is ready to read proper "user data" from a floppy disk - so I've improved the software side of things to do just that. Schematics, code, etc are all on github at github.com/gfoot/floppydisk6502 Next time we might try adding a new circuit to enable writing to disks!
6502 reading bytes from a Floppy Disk Drive
มุมมอง 3.6K2 ปีที่แล้ว
Continuing where we left off last week, let's extend the CPU interface to allow reading clock and data bytes from the floppy disk! The code is in github at github.com/gfoot/floppydisc6502, commit 9c4a3ea corresponds to this video. 00:00 Intro 00:33 Schematics 02:39 Breadboarding 07:13 Connecting to existing FDC circuit 11:23 New code 20:18 Connecting to the 6502 computer 22:35 Running the test ...
Homebrew 6502 controlling a Floppy Disk Drive
มุมมอง 4.9K2 ปีที่แล้ว
Let's build a CPU interface to allow a 6502 homebrew computer to control a Floppy Disk Drive! Previously I made a simple read controller and hooked it up to an Arduino - this time we'll focus more on the drive control signals, for things like turning the motor on and stepping the heads. The code is in github at github.com/gfoot/floppydisc6502, commit 69aeaf7 corresponds to this video. 00:00 Int...
Testing my Floppy Disc reading circuit with an Arduino
มุมมอง 4.7K3 ปีที่แล้ว
Let's make some extensions to the floppy disc reading circuit from last time to reduce the load on the CPU and so make it more stable. 00:00 Intro 01:33 Floppy disc track format 03:51 How to detect Address Marks 05:33 Updating the circuit 09:44 Testing the Address Mark detector 16:57 Fixing a clock signal timing bug 19:36 Adding a byte clock output 22:47 Testing the byte clock using the Arduino...
Reading data from a Floppy Drive
มุมมอง 9K3 ปีที่แล้ว
Let's make a circuit to read actual data bytes from a floppy disc using an Arduino! This requires reconstructing the clock for the input data, and then separating the clock and data from the FM-encoded data stream. 00:00 Intro 00:15 FM data stream 02:16 Clock recovery circuit 04:52 Building and testing the clock recovery circuit 19:26 Clock/data separation of the FM data stream 30:40 Reading se...
What causes these weird artifacts on the BBC Micro's data bus?
มุมมอง 1.6K3 ปีที่แล้ว
What causes these weird artifacts on the BBC Micro's data bus?
VGA Sprites on a 6502 breadboard computer
มุมมอง 11K3 ปีที่แล้ว
VGA Sprites on a 6502 breadboard computer
How to display VGA text output using the SCN2674 on a breadboard
มุมมอง 10K3 ปีที่แล้ว
How to display VGA text output using the SCN2674 on a breadboard
How to analyse VGA circuit timing using a spreadsheet
มุมมอง 1.8K3 ปีที่แล้ว
How to analyse VGA circuit timing using a spreadsheet
Simple 6502 Breadboard VGA - 640x480 8-colour upgrade details
มุมมอง 5K3 ปีที่แล้ว
Simple 6502 Breadboard VGA - 640x480 8-colour upgrade details
Simple 6502 Breadboard VGA - 640x480 with 8 colours
มุมมอง 2.5K3 ปีที่แล้ว
Simple 6502 Breadboard VGA - 640x480 with 8 colours
Simple Breadboard VGA - 640x480 monochrome upgrade
มุมมอง 4.3K3 ปีที่แล้ว
Simple Breadboard VGA - 640x480 monochrome upgrade
Simple Breadboard VGA - 320x480 resolution upgrade
มุมมอง 4.6K3 ปีที่แล้ว
Simple Breadboard VGA - 320x480 resolution upgrade
Soft Power Switch with Overcurrent Protection
มุมมอง 1.5K3 ปีที่แล้ว
Soft Power Switch with Overcurrent Protection
Happy Pi Day! Circle drawing on a Ben Eater 6502
มุมมอง 1.6K3 ปีที่แล้ว
Happy Pi Day! Circle drawing on a Ben Eater 6502
Simple VGA for Ben Eater's 6502 - Increasing the resolution
มุมมอง 12K3 ปีที่แล้ว
Simple VGA for Ben Eater's 6502 - Increasing the resolution
Homebrew ARM2 #8a: ARM2 Assembly Deep Dive
มุมมอง 9983 ปีที่แล้ว
Homebrew ARM2 #8a: ARM2 Assembly Deep Dive
Homebrew ARM2 #11: RAM Preloading Progress Update
มุมมอง 8993 ปีที่แล้ว
Homebrew ARM2 #11: RAM Preloading Progress Update
Raspberry Pi Pico EEPROM Programmer - PicoPROM
มุมมอง 9K3 ปีที่แล้ว
Raspberry Pi Pico EEPROM Programmer - PicoPROM