15 januari 2025 At the time of writing this page the PAL-2 has just been announced for sale, I am waiting for my kit!
So this is based upon the available documentation: User manual, Schematic, BOM.

What is the PAL-2?
The PAL-2 is a kit for an SBC in the now large family of KIM-1 clones. Ranging from the Micro-KIM to the PCB exact replica by Eduardo Casino, all share the KIM-1 ROMs, LED display and TTY interface and the 6532 RIOT instead of the 6530 RRIOT.

What makes the PAL-2 unique:

• It is a real and complete KIM-1 clone
• Available as a DIY kit with all components./li>
• The layout is close to the KIM-1.
• Application and Expansion connector with most KIM-1 signals.
• Lots of RAM in many configurable options
• Both RRIOTS 6532 on board
• TTY interface on TTL level, USB to TTL adapter included in the kit
• Power can come from USB to TTL adapter or from external 5V supply (same a KIM-1)

The PAL-2 differs from a KIM-1:

• No audio cassette circuit, not even the TTL parts
• Application and Expansion connector as 22×2 pinheader instead of PCB edge connectors
• The signals on the Application connector are not all identical: no audio, TTY instead of 20 mA loop, decoding lines added
• Not the same size PCB

The PAL-2 differs from the PAL-1:

• Improved keyboard, with labels and look of the KIM-1
• No need for a Motherboard:
  • No external RAM module required
  • No external RRIOT required
• E000-FFFF can be used freely
• Looks a lot more like a KIM-1
• Complete application and Expansion connector
• TTY on TTL level instead of (not standard) RS232

Schematic

RAM decoding
The PAL-2 has a very flexible RAM memory layout, as shown in the next parts of the schematics:

Internal ROM and external ROM
The PAL-2 has a 2K ROM with the KIM-1 monitor. Since there is no audio circuitry, the ROM from 1800-1BFF could be used for other programs, like the KIM Clone by Corsham Technology. The 28C16 is easy to program.

One of the first expansions that is to be expected is an external 8K ROM. The decoding for this ROM, e.g. an 28C64 is already present on the connectors and in the decoding circuit.
The decoding signals are 8K7_SELECT (CE on 28C64) and 8K7_ROM (OE on 28C64). Just the 28C64 IC has to be connected to address and data lines.

Application and Expansion connectors

KIM-1 Application connector

• AUDIO IN -> 8k7_SELECT
• AUDIO OUT LO -> 8K7-ROM
• TTY in and out now at TTL level for USB to TTL converter
• TTY PTR and KYBD, +1wV, AUDIO OUT LO not connected

This means, even if the edge to pin connector issue is solved, the standard KIM-1 I/O boards will not work for TTY and audio.

The expansion connector is identical to the KIM-1.

KIM-1 Expansion connector

Power
Power has to be applied in the standard KIM-1 manner to the application connector Pin 1 = GND, pin A = 5V. Note that reversing these pins will mean the dead of the PAL-2!

Expansion

As a first suggestion for a PAL-2 extension i see a board connected to Application and Extension connectors with at least:

• 28C64 (or bigger, switchable in 8K chunks) EEPROM
• Connector for the USB to TTL
• External power connector, switchable between this and USB to TTL connector
• TTY/LED keyboard switch
• Power switch

The excellent expansions by Bob Applegate for the Corsham clone will be a good inspiration, like 6522/6850 I/O board, breadboard board, motherboard.