SRAM types, please help !

[Kroko]

Hello !

I am using a 628128 128K static ram. It has the control
line /WE /OE /CS1 and CS2. I have tied /OE and /CS1 to
ground. To control writing and reading I use /WE and CS2.
This works very well, no problem. I also select and deselect
the chip with CS2.

But I now changed the RAM type and am using a V62C518256LL
32K SRAM, because it has only 28 pins and I need space on
the board.

Unfortunately it doesnt have a CS2 but only /WE /OE and /CE

I thought it would be easy to modify my ram access to use this
chip, but it doesnt work:

I tied /CE to ground and use /WE as before. I use the same signal
as for CS2 to control the /OE line, just inverted.

Well, it doesn't work....

Do you have any ideas, why this is so ?

Kroko.

 

[George]

Kroko <Kroko@nil.com> wrote in message news:<s6kp10plbk1b5os7jp443fjb3jap5bhve3@4ax.com>...

Hello !

I am using a 628128 128K static ram. It has the control
line /WE /OE /CS1 and CS2. I have tied /OE and /CS1 to
ground. To control writing and reading I use /WE and CS2.
This works very well, no problem. I also select and deselect
the chip with CS2.

But I now changed the RAM type and am using a V62C518256LL
32K SRAM, because it has only 28 pins and I need space on
the board.

Unfortunately it doesnt have a CS2 but only /WE /OE and /CE

I thought it would be easy to modify my ram access to use this
chip, but it doesnt work:

I tied /CE to ground and use /WE as before. I use the same signal
as for CS2 to control the /OE line, just inverted.

Well, it doesn't work....

Do you have any ideas, why this is so ?

Kroko.

I'm not sure why your solution doesn't work, but I would simply tie
/OE to low and send the inverted CS2 to the /CE.

 

[John Larkin]

On Sun, 01 Feb 2004 11:17:54 +0100, Kroko <Kroko@nil.com> wrote:

Hello !

I am using a 628128 128K static ram. It has the control
line /WE /OE /CS1 and CS2. I have tied /OE and /CS1 to
ground. To control writing and reading I use /WE and CS2.
This works very well, no problem. I also select and deselect
the chip with CS2.

But I now changed the RAM type and am using a V62C518256LL
32K SRAM, because it has only 28 pins and I need space on
the board.

Unfortunately it doesnt have a CS2 but only /WE /OE and /CE

I thought it would be easy to modify my ram access to use this
chip, but it doesnt work:

I tied /CE to ground and use /WE as before. I use the same signal
as for CS2 to control the /OE line, just inverted.

Well, it doesn't work....

Do you have any ideas, why this is so ?

Kroko.

Tie /OE low and drive /CE with the active-low chip select.

John

 

[Kroko]

Tie /OE low and drive /CE with the active-low chip select.

Thank you, I have also tried this when the other solution didn't work,
but it still didn't work :-(. Are there other important differences
between the chips I am using ?

I am using a 628128 128K static ram. It has the control
But I now changed the RAM type and am using a V62C518256LL

Kroko