This is the documentation for an improved version of v.0, I called it "Version 1.2". The total addressable RAM memory is still 64KB, but a few improvements have been made over v.0. Basically, this version is the equivalent of the "64K modification", meaning instead of DRAM#0, DRAM#2 si DRAM#3 (48K in total) only one 64K memory bank is used (of which only 48K are addressable), but there are a few more improvements aside from that.
Changes from v.0:
DRAM memory (48K) used can be of 3 different types (not simultaneously): 8 x 4164 chips (64K x 1 bit), 2 x 41464 chips (64K x 4 bit) or 1 x SRAM chip (128K x 8bit)
Video memory (16K) used can be of 3 different types (not simultaneously): 8 x 4164 chips (64K x 1 bit), 2 x 41464 chips (64K x 4 bit) or 1 x SRAM chip (32K x 8bit)
SRAM memory is installed on a separate board attached to the mainboard through 2 connectors
Selecting the DRAM and video memory type is done by only installing the respective chips
DRAM memory can be of a different type from the video memory at a given moment (4164 and 41464, but not DRAM and SRAM at the same time)
BOOT ROM memory can be one EPROM 2-16K chip (2716 - 27128) or an EEPROM chip 29EE010 (128K x 8)
BASIC ROM memory can be one EPROM 16-64K chip (27128 - 27512) or one EEPROM chip 29EE010 (128K x 8)
Selecting the type of BOOT ROM and BASIC ROM memory is done by configuration jumpers on the mainboard
BOOT ROM memory can be of a different type from the BASIC ROM at a given moment
Selecting the EEPROM area used is done manually by switches before power up.
Schematics - v.1.2
Version 1.2 features:
64KB total addressable RAM
64KB DRAM as 8 x 4164 chips (64Kx1bit) or 2 x 41464 chips (64Kx4bit) or 1 x SRAM chip (128Kx8bit)
16KB video RAM as 8 x 4164 chips (64Kx1bit) or 2 x 41464 chips (64Kx4bit) or 1 x SRAM chip (32Kx8bit)
2-16KB BOOT ROM as 1 x EPROM chip (2716-27128) or 1 x EEPROM chip (29EE010, 128Kx8bit)
16-64KB BASIC ROM as 1 x EPROM chip (27128-27512) or 1 x EEPROM chip (29EE010, 128Kx8bit)
Board layout - v.1.2
The component layer (above) is drawn in red and the opposite layer in blue.