Hitachi HM6116ZP-4 CMOS RAM Datasheet - Page 3 - Electronic Circuits Projects Diagrams Free

**Krumlink** · 17th March 2008, 10:39 AM

Quote:

Originally Posted by ericgibbs

hi,
If you used a 8255 PIO to connect to the 6116 SRAM, you would do the following write/read sequence.

Change the PIO's portA to output.
Set the PIO's portA to say the 8 bit data you want to write to the SRAM.
Then set the PIO's portB and portC[low nibble] to the the address [location] in the SRAM where you want the data on portA to be written.
Then set the SRAM WR and CS low and high,[using portC[high nibble] this will write the data to the addressed SRAM location.

For reading the SRAM,
Change the PIO's portA to input.
Then set the PIO's portB and portC[low] to the the address [location] in the SRAM where you want the data on portA to be read from
Then set the SRAM CS low and high, this will place the data of the addressed SRAM location onto the portA, which the program then reads.

As you can see, the write/read cycle is much longer than the 'clock' rate.

It would help if you could post a block diagram of your project.

Yes that would help a lot, I am looking for a schematic of the 8255, but it appears (from a websites description) sounds like a easy process.

Aussieproof: Yes that would also help out a lot, I PM ed you

**Krumlink** · 17th March 2008, 02:18 PM

I have the datasheets for 8255 and the 6116, so it is easier to understand what you are talking about (eric). I am wondering though how I would put the SRAM in standby mode, aka hold the data (since it's static ram). What's the minimal amout of power can I feed it just so it hold's its data? The power to everything else will be off. I still want to feed it the 5V line when the entire computer turns on.

So I was thinking cannabalizing some of my 4.8V batteries (taking the plastic thing off) and making a 9.6V battery pack, that way I can put it parallel to the 12V line, so it charges the battery through a current limiting resistor, then the battery goes through a 5V regulator that will only be switched on when I am about to turn off the computer. Here's what Im thinking of in a paint schematic pain stakingly drawn

ericgibbs · 17th March 2008, 02:57 PM

hi,
Can you get the LA version of the 6116. It is designed for data retention down to 2V with standby currents of less than 10mA.???

There are also non volatile Rams, with inbuilt battery and auto switchover at power down/up. Ref the Dallas range of ic's.

**Krumlink** · 17th March 2008, 08:17 PM

Quote:

Originally Posted by ericgibbs

hi,
Can you get the LA version of the 6116. It is designed for data retention down to 2V with standby currents of less than 10mA.???

There are also non volatile Rams, with inbuilt battery and auto switchover at power down/up. Ref the Dallas range of ic's.

I will see if aussie has the LA series, but I want to stick to the 6116

kchriste · 18th March 2008, 05:05 AM

You should be able to back the data up in a 6116LA for several years with a pair of AAA batteries because the chip typically draws VERY little current (typ 2uA) in standby mode.

**Nigel Goodwin** · 18th March 2008, 10:17 AM

Quote:

Originally Posted by kchriste

You should be able to back the data up in a 6116LA for several years with a pair of AAA batteries because the chip typically draws VERY little current (typ 2uA) in standby mode.

I would check what's still in mine, but they haven't been powered for 20 years or so, and the backup was a NICAD, which don't last very long

It's in a Microtan65 system, plugged in the backplane, and can be page selected in place of the normal expansion RAM - so you could load programs off tape into the 6116's, then just run them from there, and they were still there the next time you powered up. I actually bought the 6116 board as a kit from the guy who designed and sold them, I can't remember where he lived now, but it wasn't too far away, and I fetched it from his house.

**Krumlink** · 19th March 2008, 02:15 AM

Ok, after reading what eric posted I am still having problems understanding what he is saying.

Quote:

Change the PIO's portA to output.
Set the PIO's portA to say the 8 bit data you want to write to the SRAM.
Then set the PIO's portB and portC[low nibble] to the the address [location] in the SRAM where you want the data on portA to be written.
Then set the SRAM WR and CS low and high,[using portC[high nibble] this will write the data to the addressed SRAM location.

For reading the SRAM,
Change the PIO's portA to input.
Then set the PIO's portB and portC[low] to the the address [location] in the SRAM where you want the data on portA to be read from
Then set the SRAM CS low and high, this will place the data of the addressed SRAM location onto the portA, which the program then reads.

As you can see, the write/read cycle is much longer than the 'clock' rate.

It would help if you could post a block diagram of your project.

kchriste · 19th March 2008, 03:01 AM

Krumlink,
You'll have more fun with a bunch of LEDs and toggle switches connected to your RAM chip than playing around with 8255s or PIO chips. The 8255 or PIO is only "helpful" if you want to control the RAM chip from a micro controller and would be a hindrance to your relay based CPU in my opinion.
Nigel,
I checked my old Z80 project which I built in 1989. I think I have changed the batteries once or twice and the RAM data is still valid today! I'm powering two 6116's with a pair of AAA batteries:

Pommie · 19th March 2008, 03:18 AM

kchriste,

Prepare to be bombarded with questions and schematic requests from Mark256.

Mike.

kchriste · 19th March 2008, 03:38 AM

I think I already provided him with diagram snippets of it a few years ago. I think Marks256 is over the Z80, but Krumlink appears to be on the way to Z80 land. But first he must pass through relay hell and fight the Back EMF wizard with his trusty diode!

blueroomelectronics · 19th March 2008, 04:07 AM

Nice work on the Z80.
Is the keyboard made of paper?

kchriste · 19th March 2008, 04:38 AM

Thanks, it was my final year project at BCIT. Yes, the part you see is a piece of tape covered paper. The actual keyboard was one scavenged from an old calculator; the kind with metal popples on a PCB. I drew my custom buttons on a piece of paper with colored pens, covered it with clear tape for durability, and glued it on top of the popple PCB. The display was robbed from the same calculator.

**Nigel Goodwin** · 19th March 2008, 09:18 AM

Quote:

Originally Posted by kchriste

Nigel,
I checked my old Z80 project which I built in 1989. I think I have changed the batteries once or twice and the RAM data is still valid today! I'm powering two 6116's with a pair of AAA batteries:

As far as I remember, mine used a NICAD, and the life of those is VERY limited! - I'll try and dig it out and post a picture

**Krumlink** · 19th March 2008, 12:36 PM

So this is what I think:
1. Data input into the I/O lines.
2. Switch Addresses with the Address inputs with Binary, aka address line 1 in 000 0000 0001 and 37 in 000 0010 0101 correct?
3. All this will be configured with the Write enable and the Read enable stuff, which is easy. I believe I gotz it correct?

(Then to keep the chip alive I enable CS (Chip select) and GND, or so I think?

kchriste · 20th March 2008, 02:13 AM

Yes.
Set your address lines.
Put the data you want to load on the IO lines.
Make CS low. ( WR and OE are already high )
Make WR low and then high again.
The data is now stored at one address location.

To read the data back:
Set your address lines the same as above.
Make CS low. ( WR and OE are high )
Make OE low.
The data is now being outputted on the IO pins.
Make CS and OE high again and the chip is asleep with the data still valid inside it and the IO pins are disabled.
Note: The IO pins are typically connected to the data buss of a CPU. They are inputs when WR & CS are low and are outputs when OE & CS are low. They do nothing when CS is high and the RAM is asleep.

17th March 2008, 02:57 PM	(permalink)
ericgibbs Experienced Member	hi, Can you get the LA version of the 6116. It is designed for data retention down to 2V with standby currents of less than 10mA.??? There are also non volatile Rams, with inbuilt battery and auto switchover at power down/up. Ref the Dallas range of ic's. __________________ Eric "Good enough is Perfect" PIC tutorials: Gramo's: www.digital-diy.net/ Bill's: www.blueroomelectronics.com/

18th March 2008, 05:05 AM	(permalink)
kchriste Experienced Member	You should be able to back the data up in a 6116LA for several years with a pair of AAA batteries because the chip typically draws VERY little current (typ 2uA) in standby mode. __________________ --- The days of the digital watch are numbered. ---

19th March 2008, 03:38 AM	(permalink)
kchriste Experienced Member	I think I already provided him with diagram snippets of it a few years ago. I think Marks256 is over the Z80, but Krumlink appears to be on the way to Z80 land. But first he must pass through relay hell and fight the Back EMF wizard with his trusty diode! __________________ --- The days of the digital watch are numbered. ---

19th March 2008, 04:07 AM	(permalink)
blueroomelectronics Experienced Member Blog Entries: 4	Nice work on the Z80. Is the keyboard made of paper? __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com

19th March 2008, 04:38 AM	(permalink)
kchriste Experienced Member	Thanks, it was my final year project at BCIT. Yes, the part you see is a piece of tape covered paper. The actual keyboard was one scavenged from an old calculator; the kind with metal popples on a PCB. I drew my custom buttons on a piece of paper with colored pens, covered it with clear tape for durability, and glued it on top of the popple PCB. The display was robbed from the same calculator. __________________ --- The days of the digital watch are numbered. ---

19th March 2008, 03:18 AM	(permalink)
Pommie Experienced Member	kchriste, Prepare to be bombarded with questions and schematic requests from Mark256. Mike.

19th March 2008, 12:36 PM	(permalink)
Krumlink Moderator Blog Entries: 1	So this is what I think: 1. Data input into the I/O lines. 2. Switch Addresses with the Address inputs with Binary, aka address line 1 in 000 0000 0001 and 37 in 000 0010 0101 correct? 3. All this will be configured with the Write enable and the Read enable stuff, which is easy. I believe I gotz it correct? (Then to keep the chip alive I enable CS (Chip select) and GND, or so I think? __________________ MechTronics

20th March 2008, 02:13 AM	(permalink)
kchriste Experienced Member	Yes. Set your address lines. Put the data you want to load on the IO lines. Make CS low. ( WR and OE are already high ) Make WR low and then high again. The data is now stored at one address location. To read the data back: Set your address lines the same as above. Make CS low. ( WR and OE are high ) Make OE low. The data is now being outputted on the IO pins. Make CS and OE high again and the chip is asleep with the data still valid inside it and the IO pins are disabled. Note: The IO pins are typically connected to the data buss of a CPU. They are inputs when WR & CS are low and are outputs when OE & CS are low. They do nothing when CS is high and the RAM is asleep. __________________ --- The days of the digital watch are numbered. --- Last edited by kchriste; 20th March 2008 at 02:22 AM.

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