LPC Microcontrollers中的主题 Re: What could be practical reason for using two 1MB Static RAM chips on LPC1788?

What could be practical reason for using two 1MB Static RAM chips on LPC1788?

Eugene723 — Fri, 21 Jul 2023 12:49:31 GMT

I recently took on support for a board designed by others about 10 years ago. There are two 8Mbit (1MB) CY7C1051 chips on this board.

LPC1788 has four Chip Selects (CS0 through CS3) each supporting up to 64MB of static RAM.

I don’t have much hardware design knowledge hence my question. I briefly checked on pricing and noticed that one 4MB chip costs about as much as two 1MB while providing two times memory amount.

What could be the reason to design two separate 1MB chips as opposite to one of a larger size?

Thank you,

Eugene

Re: What could be practical reason for using two 1MB Static RAM chips on LPC1788?

Alice_Yang — Mon, 24 Jul 2023 12:29:38 GMT

Hello @Eugene723

Maybe one SRAM is broken, anther one can used.

Also for the chip costs, you need check the same company and same series.

Alice

Re: What could be practical reason for using two 1MB Static RAM chips on LPC1788?

Eugene723 — Mon, 24 Jul 2023 12:50:51 GMT

Thank you, Alice.

These chips are used for background and foreground frames for LCD so, if one were broken the entire board would stop functioning…

I just wanted to verify that there is no some sort of “symmetrical” reason - as for example, in desktop PCs it’s required to plug identical memory modules in slots 1 and 3; then 2 and 4.

Eugene

Re: What could be practical reason for using two 1MB Static RAM chips on LPC1788?

Alice_Yang — Tue, 25 Jul 2023 08:57:35 GMT

Hello @Eugene723

"I just wanted to verify that there is no some sort of “symmetrical” reason - as for example, in desktop PCs it’s required to plug identical memory modules in slots 1 and 3; then 2 and 4."

->> For LPC1788, no such limitation.

"one 4MB chip costs about as much as two 1MB while providing two times memory amount."

->> Recommend using one 4MB chip as this situation.

Alice