HP 49G Advantages over 49g+ & 50g
|
01-24-2018, 12:32 PM
(This post was last modified: 01-25-2018 09:16 AM by jebem.)
Post: #18
|
|||
|
|||
RE: HP 49G Advantages over 49g+ & 50g
(01-23-2018 04:12 PM)Dave Britten Wrote:(01-23-2018 03:28 PM)jebem Wrote: <Question on what ERAM and IRAM means> I thought the same way, but it seems that this is not the case. Meanwhile I have been doing further reading here and there, and: - I have learn that IRAM means "Independent RAM", as found on several HP-71 documents available elsewhere. The 71B was the first machine to use the Saturn processor. - I also learned that the Saturn processor does NOT have internal RAM to store programs. Its internal SRAM is dedicated to support the CPU Registers. - So, all the SRAM (static RAM), FLASH ROM, or SD Cards, must be External to the Saturn processor. - The internal PCB pictures I found at HPCALC shows, among other chips: - One TE28F160 16Mbit FLASH ROM; - One KM684000BLT-5 512KByte SRAM. This makes sense with what we see on the 49G File Manager information: Model 49G (ID93406767, Indonesia, 1999, week 34) VERSION: HP49-C Revision #1.18 HP 2000 Port 0: IRAM 241KB Port 1: ERAM 255KB Port 2: FLASH 1079KB Home 241KB (that's the shared Port 0 from above) Also, as I mentioned above in another post, while the IRAM is Volatile static RAM shared with "System RAM" and cleared by a memory clear operation, the ERAM it's not shared with "system RAM" and is not cleared by a memory clear operation. So, it seems that despite using one single 512KByte SRAM chip shared among ports 0 and 1, each segment is handled in a different way by the calculator kernel. And the question remains: What the ERAM acronym means? I'm hoping that one of the HP gurus read this and give me an answer, any answer at all will be good Jose Mesquita RadioMuseum.org member |
|||
« Next Oldest | Next Newest »
|
User(s) browsing this thread: 1 Guest(s)