Asie of ZZT reconstruction fame observed this auction:
https://zenmarket.jp/en/auction.aspx?it ... d496192012 ( https://archive.ph/T1bBe ) = https://page.auctions.yahoo.co.jp/jp/auction/d496192012
which has pictures of a not-previously-documented board for the WonderSwan, PTS-0102.
Visible on the component side are:
Battery socket
SW3, SW1, and SW2, respectively 2, 4, and 6 position DIP switches
"GIZA" battery management chip
U1 2003
U6, 8-pin unknown
U7 S-3711A RTC chip and X1 its 32KiHz crystal
Some unknown connector or switch in the corner
Solder jumpers J1, J2, J3
On the solder side
U3, BSI BS62LV4000STC-70 4mebibit SRAM
U4 and U5, Fujitsu 29LV160T-90PFTN 16 mebibit Flash
From the photo in the auction, currently on the cart there is some program to assist with self-flashing.
Wonderswan prototype cart
Re: Wonderswan prototype cart
Due to it mostly being preserved in the form of obscure forum posts and Twitter remarks, I have created a listing of known prototype WonderSwan hardware, available here.