6502 X-Ray

6502 X-Ray is a tool for visualizing the connectivity inside the 6502 chip. It uses the data from the Visual 6502 project [1].

Support for other chips such as the 6800 may be added later.

[1] http://visual6502.org/

Dependencies

Requirements for running are Python 2.7, PyCairo and Gtk3 (through gi.repository).

In the case of Ubuntu or Debian-ish distros use:

apt-get install python-cairo python-gi python-gi-cairo

Starting

usage: xray6502.py [-h] [-n NODE] [FILE [FILE ...]]

6502 chip visualization tool

positional arguments:
  FILE                  Overlay data files (JSON) to load

optional arguments:
  -h, --help            show this help message and exit
  -n NODE, --node NODE  Highlight a node at start

Usage

Hover over the chip overview to show information about nodes in the infobox. To lock the selection, click with the left mouse button (use right mouse button to unlock).

Further navigation can be done by clicking on node numbers in the infobox, or selecting another node in the chip overview. Use backspace to go back to the last selected node.

With x, the context of the selected node (those nodes connected through transistors) will be shown as well.

The data shown in the infobox can be switched with 'n'. This will either show per-node or per-group information. A group here is a group of nodes connected through c1 and c2 of transistors.

Node mode shows the connected transistors. The top table shows the transistors connected to this node through C1 or C2, with the node connected to the gate and the node connected to the other side of the transistor being shown. The bottom table shows the C1 and C2s for transistors for which this node is connected to the gate.

Group mode shows the nodes in the connected group. If there is one output and this output can be interpreted as a boolean expression of the inputs, this expression is shown.

Keyboard shortcuts

Key	Description
+, >	Zoom in
-, <	Zoom out
0	Reset zoom
[shift-]Left	Scroll left
[shift-]Right	Scroll right
[shift-]Up	Scroll up
[shift-]Down	Scroll down
n	Toggle between showing group and node information
,	Previous frame
.	Next frame
x	Show extended context: upstream/downstream links for selected node
s	Make screenshot
BackSpace	Go to previous selection

Overlay files

Overlay files can be loaded to show more information on the chip map. These are simple json files with the following format:

{
    "title": "Title of this overlay",
    "values": [1.0, 0.0, ...],
    "tags": [1, 0, 1, 0],
    "cycle": <half-cycle number>,
    "PC": <current PC address>
}

• title specifies a title for this overlay, this is shown to the user
• values are scalar values from 0.0 to 1.0 per node
• tags are bitwise tags per node
• cycle is the current half-cycle, this is shown to the user
• PC is the current instruction pointer address, this is shown to the user

All of the keys are optional. Multiple data files can be read, in which case , and . can be used to browse between the frames.

Authors

• Wladimir J. van der Laan [email protected]