new Casio’s fx-CG50

[jebem]

(01-31-2017 03:19 PM)jebem Wrote:  

(01-30-2017 08:58 PM)rprosperi Wrote:  According to the Casio Europe website, this is the Specification for memory:
"◦Available RAM/Flash ROM memory: 61 kB/16 MB"
This MUST be typo!? Above was copy/pasted, to be sure I didn't introduce an error.

I believe those are the correct values.

This question from Bob is a very good one, and my reply contains misleading information.
My answer was given based on the CASIO officially available information, but I found it suspicious as well. Then I forgot about it, until a recent CASIO announcement for the GRAPH 90+E equivalent model for French market.

Yet Casio keeps on supplying confusing information (May-2018) on the so called "fx-CG50 Hardware User's Guide":
- Programming capacity: 61,000 bytes (max.)
- Storage memory capacity: fx-CG50: 16MB (max.) fx-CG50: 4.5MB (max.)

I now realize that those values are referred to the end user available usable spaces, not to the actual RAM/ROM configured sizes.
So, the user would have around 61Kbyte of programming area, and a maximum of 16MByte of storage area on a fx-CG50.

Meanwhile I found a few pictures of the internal PCB at TI-Planet and a lot of investigation going on there as well, and that allowed me to find out the exact memory configurations:

- RAM: ESMT M12L64164A-7TI 8MByte SDRAM (versus 2MByte SRAM on CG10/20)
- Storage/ROM: SPANSION S99-50272 16M 16-bit words Flash ROM

A lot of people comments that there is no information available on the SPANSION S99-50272 chip, and some of them comments that it is a 16MByte chip.
Well, it is not. As correctly stated on Casiopeia Forum, this is a 32MByte chip.

And it makes sense to me, for two reasons:
- The Hitachi/Renesas custom made SH7305 processor for Casio fx-CG machines, uses a 16-bit data path.
- The Firmware OS would take a substantial amount of storage, increased if additional applications are installed (the latest 3.11 update fx-CG50 Series OS Ver.3.11 Update.exe file takes 19.7MByte, so I expect the base firmware to take close to 16MByte).
Therefore, a 16M 16-bit words (32MByte) storage is required to accommodate the firmware, additional apps, and leave the referred 16MByte of storage to the suer.

And I was lucky. I found the official Cypress (SPANSION's owners) product notification information containg the equivalence table from the PANSION S99-50272 to the
Cypress S29GL256S90TFI020.

Concerning the processor, there is a consensus on the SH7305, despite CASIO not disclosing information about it.
It seems to be similar to the standard SH7724 (which is documented), according to someone that should know what it is talking about, since he successfully built several overclock tools for those Casio calculators.