First up, I have added Li'l Bro ii versions of the final two games released by Unisonic. As before, you can download the ROMs, box art and instructions over in the programming forum, here:
Surely though, a 40th birthday is worthy of more celebration than a rehash of four card game cartridges and the worst version of Math Fun ever?
Well, let's wait and see...
The rest of this is defintely only for those that do not suffer from TL;DR...
What was your idea to take "Linus"?
I was actually aiming for Linus' little brother, Rerun Van Pelt (it seemed appropriate). However, being a Peanuts lightweight I think I might have accidentally picked an image of Linus for the box art. Ahh well.
Wow, I never heard of the Unisonic console until now.
Given the discussion of the Champion I thought a brief run down of why it is considered the Intellivision's little brother and why it is so rubbish might be helpful for those that are unfamiliar with the machine.
The Unisonic Champion is a microprocessor based cartridge system that shares the rather unusual CP-1610 CPU and 10bit ROMs with the Intellivision.
the Unisonic Champion is the "Mid Range".
As Lathe26 and mr_me highlight, like the Intellivision, the Unisonic Champion is based on a General Instrument reference design, in this case the Gimini Mid-Range system:
Like the Gimini Deluxe design that underpins the Intellivision, the graphics chip in the Mid-Range system, the Graphics Interface Chip (GIC), is the heart of the design and controls everything, including the CPU.
Whilst the Intellivision's graphics chip (the STIC) is quirky and a bit flawed, as a general purpose graphics chip the GIC is a total disaster of a design. Now you might be thinking this is a bit harsh, as the GIC is clearly aimed at card video games. However, the various GI datasheets list 15 distinct cartridge titles, none of which are card games; and Unisonic marketed the Champion as 'fully programmable for unlimited family fun'. Therefore, both GI and Unisonic clearly hoped the GIC could be used more generally, and both were deluded.
The GIC has one, tile based video mode, which splits the screen into two areas, as shown below. On the left it is 6x12 characters, on the right 13x6 tiles. Each line is split in memory with rows in the left column occupying addresses $00-$47 and the right $48-$95. This makes implementing horizontal games that don't naturally fit into this split screen format hard.
There are no sprites or MOBs, and the font is limited, with only 64 uppercase characters and minimal graphics, none of which can be redefined.
It's interesting that Lil' Bro had smaller fonts than its big brother.
As has been noted, the font is 5x7 pixels, effectively 6x8 pixels once you add a 1 pixel border to prevent letters hitting each other. On the right hand side the 5x7 font fits into double height characters that are 9x16. So, the overall resolution (if you can call it that) is 153x96. In Li'l Bro all 6x8 characters are centred in an 8x8 Intellivision card, so the font is correct, but the spacing is not quite right (too widely spaced on the left, too closely on the right, as you can see below). You will also notice that some of the characters differ between MAME and Li'l Bro. Li'l Bro takes its font from the AY-3-8800 die shot dump by Sean Riddle, I think the MAME implementation may pre-date this.
Although it looks to be a colour system, the Champion is really monochrome. The overall background has to be green and foreground white. The only exception to this are the background colours of the double height card symbols. These can only be drawn on the right side of the screen. Effectively every character has a specific background colour that cannot be changed by the programmer.
Therefore, the only characters that can be displayed consistently across the full effective 19x6 character screen is one of 59 white upper case alpha-numeric text characters on a green background.
Everyone knows the CP-1610 is s-l-o-w, and the Intellivision's STIC annoyingly steals about 10% of the CPU time. However, the GIC in the Champion shuts the CP-1610 down for 75% of the time while it draws the whole screen. As a consequence the Unisonic Champion is really slow (about 25,000 intructions/sec).
The system only has 256 bytes of 8bit RAM and no 16bit RAM. Of the 256 bytes, 151 are dedicated to the GIC leaving 105 bytes for other uses. However, the bigger problem is the lack of 16bit RAM, which partly breaks the CP-1610 subroutine mechanism, as it is not easy to store and retrieve subroutine return addresses to an 8 bit stack. As a consequence, reusable functions carry a greater time and memory overhead.
It is probably not possible to add 16 bit RAM to the system in a cartridge, or make games bigger than 4K without using bankswitching. This is because it looks as though pins AD13-AD15 of the CP-1610 are tied to ground on the motherboard! This limits the address space to 8K and precludes the use of 16bit RAM or ROMs on a cartridge. Like the Intellivision much of the bottom 4K of the address space contains the GIC and EXEC, making it unavailable for games. Bizarrely, the shorted CPU signals do seem to be routed to the cartridge port, presumably just to taunt developers.
Somewhere down the line the AY-3-8910 programmable sound generator (PSG) in the system diagram above was removed from the Gimini reference design, as can be seen below. This was probably done to save cost and means that Unisonic Champion sound is supplied by a single channel beeper within the GIC with three, really annoying tones.
A side effect of removing the PSG, was that the controller inputs probably had to be rethought. The resulting design uses very limited hardware and led to each player only having two buttons, YES and NO, nothing else. No joystick, no action / fire buttons, nothing. Although there is a Reset button on each controller, this is directly connected to the GIC's reset line, and therefore, cannot be read by a program or repurposed.
At least the controllers are cordless, that's quite something but limits it to this two (three) buttons if you used only a single channel.
Although some images might suggest that these controllers are wireless, this is not correct, as can be seen here:
To describe this lot as crippling is a significant understatement. Unsurprisingly the Unisonic Champion was a commercial failure and, as a consequence, it is rarer than hen's teeth today. The very few that were made were sold in the US and Japan.
If you want to know more, the Unisonic Champion FAQ, Paul Robson's 2013 Retrochallenge pages, JoeZ's copies of the GI datasheets and this forum thread are great places to look.
Edited by decle, Thu Jan 11, 2018 1:02 PM.