Autopsy:

Here you can see a hack of my dtv (Direct-to-TV).

from Wikipedia:

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 self-taught computer chip designer who had formerly designed the C-One.

Tulip Computers (which had acquired the Commodore brand name in 1997) licensed the rights to Ironstone Partners, which cooperated with DC Studios, Mammoth Toys, and “The Toy:Lobster Company” in the development and marketing of the unit.[1] QVC purchased the entire first production run of 250,000 units and sold 70,000 of them the first day they were offered.

There exist multiple versions of the C64DTV. DTV1 (NTSC television type) comes with 2 MB ROM. It first appeared in late 2004 for the American/Canadian market. DTV2 (called C64D2TV sometimes) is a revised version for the European and world markets (PAL television type) and appeared in late 2005. The ROM has been replaced by flash memory in these devices. However, the DTV2/PAL version suffers from a manufacturing fault, which results in poor colour rendering (the resistors in the R-2R ladder DACs for both the chroma and the luma have been transposed). In the DTV3, a problem with the blitter was fixed. Another DTV variant is the Radio Shack “HUMMER Off-Road Racing Challenge Video Game”.

Hardware Specifications:

Core circuity:

• ASIC running at 32 MHz internally, implementing 6510 CPU, VIC-II, SID, CIA, and PLA

Casing/Connectors:

• Integrated in a Joystick (as if connected to port 2 of a real C64)
• Five additional buttons (acting like keys)
• Running from batteries only (four AA batteries)
• Composite Video, monaural audio (RCA connectors)
• Looks similar to a Competition Pro joystick

Graphics:

• NTSC (DTV2 and later: NTSC/PAL on chip, only PAL wired in end-market devices)
• Reprogrammable palette with 4 bits of luma and 4 bits of chroma
• DTV2 and later: “chunky” 256 color mode, additional blitter for fast image transformation

Sound:

• No support for SID filters
• DTV2 and later: 8 bit digital sound, additional options for envelope generators

Memory:   

• DTV1: 128 KB RAM, 2 MB ROM
• DTV2 and later: 2 MB RAM, 2 MB flash memory
• DMA engine for RAM/RAM and ROM/RAM transfers
• DTV2 and later: additional RAM access using bank switching and blitter

CPU:

• Implementing a 6510 at 1 MHz
• DTV2 and later: Enhanced CPU (fast/burst mode, additional registers and opcodes, support for illegal ops of the 6510)

source: wikipedia dtvhacking.retrosafe.com