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--- blog:commodore_c64_dtv_hacking [2023/01/22 09:32] – [PS/2 Keyboard Connection] john
+++ blog:commodore_c64_dtv_hacking [2023/01/31 11:29] (current) – [Power Supply] john
@@ Line 1: / Line 1: @@
 ====== Commodore C64 DTV Hacking ======
-All pinouts below are looking in to the connector, //not the solder side//, unless otherwise states.
+From [[https://en.wikipedia.org/wiki/C64_Direct-to-TV|Wikipedia]]:
-All diagrams are correct for the DTV v2 (aka 'PAL') unit. DTV v1 and 'Hummer' models differ.
+> The C64 Direct-to-TV, called C64DTV for short, is a single-chip implementation of the Commodore 64 computer, contained in a joystick (modeled after the mid-1980s Competition Pro
+> joystick), with 30 built-in games. The design is similar to the Atari Classics 10-in-1 TV Game. The circuitry of the C64DTV was designed by Jeri Ellsworth, a computer chip designer who
+> had previously designed the C-One.
+These are my notes on converting the C64 DTV into a capable, full-featured 8bit computer system. I've written these notes down since a lot of the information on the C64 DTV has been lost over the years. This is a combination of the old web pages I've found, technical specs and my own findings/diagrams used to build my own C64 DTV Computer System.
+{{:blog:c64:commodore64_dtv_mugshot-x600.jpg?200|}}
+Firstly, there are some key things to look out for with the different versions of the DTV:
+== DTV (version 1) ==
+  * 128 kbytes RAM
+  * 2048 kbytes ROM
+  * DMA memory transfer engine
+  * Example serial/date codes:
+    * 041107
+    * 041103
+== DTV (version 2) ==
+  * 2048 kbytes RAM
+  * 2048 kbytes Flash
+  * DMA memory transfer engine
+  * Blitter engine with bugged transparency mode - //not-fixable//
+  * 256 colour 'chunky' display mode
+  * 8bit digital audio
+  * Chroma/Luma bugged - //fixable//
+  * Example serial/date codes:
+     * 050728
+     * 050919
+     * 050921
+     * 050927
+== DTV (version 3) ==
+  * 2048 kbytes RAM
+  * 2048 kbytes Flash
+  * DMA memory transfer engine
+  * Blitter engine - //working transparency//
+  * 256 colour 'chunky' display mode
+  * 8bit digital audio
+  * Chroma/Luma output fixed
+  * Example serial/date codes:
+      * 050927
+      * 051005
+      * 051008
+      * 060118
+== Hummer Game ==
+The 'Hummer' offroad game model is mostly similar to the later DTV (version 3), so has all of the bugged-features fixes, //but// a number of useful signals are not present on the board (i.e. it doesn't have all the joystick lines available), so it presents more of a challenge.
+----
+Realistically, the //best// version is clearly the DTV (version 3) which has all of the bugs fixed. But the DTV (version 2) is definitely useable if you are prepared to fix the Chroma/Luma output (linked below). Non-working blitter transparency is a pain, but could be worked around. If you want to take advantage of the unique DTV features, then the DTV (version 1) is **not** what you want.
+You can see that there is a period in September 2005 when the production of the DTV (version 2) change to the (version 3). If you want a fixed model then you need to look for serial numbers around or above **0509xx**.
 ==== Power Supply ====
-The DTV normally gets ~6v from 4x AA batteries in the joystick. But also has a red LED connected which regulates down the supply to the 3.3v circuitry on the PCB, as used by a number of the chips. If the DTV is removed from the case and original power switch and LED, it is important that a LED is refitted to remain as a regulator.
+The DTV normally gets ~6v from 4x AA batteries in the joystick. But also has a red LED connected which is used as part of the regulator circuit to reduce the supply down to the 3.3v circuitry on the PCB, as used by a number of the chips. If the DTV is removed from the case and original power switch and LED, it is important that a LED is refitted to remain as a regulator.
 //Note: The LED should have a **forward voltage** rating of **1.8v**.//
+=== Power Switch Wiring - DTV 1 ===
+On a DTV 1, the power switch is wired as follows:
+{{:blog:c64:img20230128171536.jpg?500|}}
+Note that the (black) ground wire is soldered directly to the battery tab (the - terminal). The floating (red) positive wire is soldered to the battery tab (+ terminal).
+=== Power Switch Sub-Board ===
+A more detailed image of the power switch sub-board:
+{{:blog:c64:img20230131102833.jpg?400|}}
+From left to right, the connections above are:
+   * LED - (~+3.3v return to PCB)
+   * LED + (+5v from PCB)
+   * VDD + (+5v to PCB, connected by switch)
+   * VCC + (+5v from battery compartment, connected to switch)
+Seen from above, and with the plastic cover removed, the power supply sub-board also has markings to indicate the connections:
+{{:blog:c64:img20230131103754.jpg?400|}}
+In summary:
+{{:blog:c64:c64_dtv_v1_psu.png?500|}}
+=== Power Switch Wiring - DTV 2/3 ===
 ==== Joystick Port 1 ====