WRAM pinout

Pinout
____________________                   |                    |             +5V -- | 01. 64 | -- GND CPU D4 <> | 02             63 | <> CPU D3          CPU D5 <> | 03              62 | <> CPU D2          CPU D6 <> | 04              61 | <> CPU D1          CPU D7 <> | 05              60 | <> CPU D0      SYSTEM CLK -> | 06              59 | <- CPU /WR REFRESH -> | 07             58 | <- /PWR /RESET -> | 08             57 | <- CPU /RD NC -- | 09             56 | <- /PRD CS1 (+5V) -> | 10             55 | ?? G (NC) CS2 (+5V) -> | 11             54 | <- PA1 CS3 (+5V) -> | 12             53 | <- PA0 /CS1 (GND) -> | 13             52 | <- PS3 (+5V) /CS2 (GND) -> | 14             51 | <- PS2 (+5V) /CS3 (/WRAMSEL) -> | 15  Nintendo   50 | <- PS1 (PA7)                    Orientation: +5V -- | 16   S-WRAM    49 | -- +5V GND -- | 17             48 | -- GND                       64         33 NC -- | 18             47 | <- /PS5 (PA6)                 |         | NC -- | 19             46 | <- /PS4 (PA5)                .---. NC -- | 20             45 | <- /PS3 (PA4)                | Nintendo  | NC -- | 21             44 | <- /PS2 (PA3)                |  S-WRAM  O|              NC -- | 22              43 | <- /PS1 (PA2)                |. |         CPU A0 -> | 23              42 | <- ENABLE (A22)              '---' CPU A9 -> | 24             41 | <- CPU A8                     |         | CPU A1 -> | 25             40 | <- CPU A16                   01         32 CPU A10 -> | 26             39 | <- CPU A7          CPU A2 -> | 27              38 | <- CPU A15               Legend: CPU A11 -> | 28             37 | <- CPU A6                          CPU A3 -> | 29              36 | <- CPU A14               --[S-WRAM]-- Power, n/a CPU A12 -> | 30     O       35 | <- CPU A5                ->[S-WRAM]<- S-WRAM input CPU A4 -> | 31             34 | <- CPU A13               <-[S-WRAM]-> S-WRAM output +5V -- | 32             33 | -- GND                   <>[S-WRAM]<> Bidirectional |____________________|                         ??[S-WRAM]?? Unknown

Signal descriptions

 * ENABLE: This enables WRAM A16 (and possibly also A15..13) and is connected to CPU A22, allowing CPU A16 to address different RAM in banks $7E and $7F, but not elsewhere (resulting in the same 8 KiB in the other banks).
 * /CS3: CPU select, connected to the CPU's /WRAMSEL output to map S-WRAM to CPU bus addresses $00-3F,80-BF:0000-1FFF and $7E-7F:0000-FFFF.
 * PS1, /PS5..1: Peripheral select, connected to PA7..2 to map S-WRAM to peripheral bus addresses $80-83.
 * PA1..0: These select the S-WRAM register being accessed on the peripheral bus (WRAM data or address).
 * G: Suspected to be an output indicating whether S-WRAM is selected on either bus. This has been seen outputting low while the console is held in reset and spiking high while running.