About the PT-110 Additional memory
+++ For understanding of the memory bank configration of PT-110 +++
下に、翻訳文を添えてあります。
14288 HeroHero3 ： 2021/2/8 (月)
> PT-110 Additional memory
*Introduction
The PT-110 is a smaller version of the ThinkPad 230cs.
So the design is very similar to that.
There are also many similarities in his subsequent ThinkPad 530cs.
Information on these two models will be helpful.
The CPU of the PT-110 is an i486SX and the data bus is 32bit.
So we need 32 data lines.
And there are 4 memory banks from 0 to 3.
* Bank 0: 4MB of main board.
* Bank 1: Can be used by scraping the resist of BGA and soldering.
* Banks 2 and 3: Used for additional memory.
* Each memory bank can be equipped with 0,2,4,8,16MB of memory.
(I remember it was)
* CPU can use 32MB of memory.
(Some memory areas are reserved)
The information needed to modify the genuine additional memory can be found in the data sheet that can be downloaded from the archive below.
Search for information on the following chips from "datasheetarchive.com".
(1) HM51W16160
(2) HM5165165A
(3) HM5113165
You can download it from the "PDF" button at the top right.
The genuine 4MB expansion memory uses bank 2.
It is equipped with two HM51W16160 (or HM51W16180).
It is printed U1, U2 on the PCB.
The pin assignment on page 3 of the data sheet (1) is the basis for the modification.
Supplement to pin assignment footnotes ...
* I / O 0-15: Data line (32bit = 1 bank with 2 chips)
* Lines other than I / O, UCAS, LCAS, and WE are common to 2 chips.
* The signal with the bar above is the inverse logic signal (Hi = off, Lo = on)
* OE is always Lo (always output is possible)
* NC is an unconnected terminal, so it can be ignored.
* A0-11: For the address line, specify the memory cells arranged in a grid pattern by entering the values twice in the row and column.
(However, since the grid is not square, use A0-11 for rows and A0-7 for columns)
And before EDO memory, reading and writing is possible if the memory cell exists at the address specified by the address line.
In other words, in the case of HM51W16160, A0-7 is swappable.
The A8-A11 are also swappable, too.
Note: It is important that address line swapping is possible within the two ranges.
With DDR memory, multiple consecutive data can be retrieved once the address is specified, so it is not possible to swapp the address lines.
> PT-110追加（拡張）メモリ