I am designing a new device, and plan to use the MK20DX64VLH7 Kinetis MUC. This system need 256kB external SRAM.
I have read the thread K20 external memory interface description wanted. But still not absolute sure. From the datasheet of the MK20DX64VLH7, there are FB_AD[17:0], FB_RW, FB_ALE/CS1/TS, FB_CS0#.
The SRAM Chip have A[17:0], D[15:0], WE#, OE#, CS1# and CS2.
Can i use that SRAM in multiplexed mode, by
latching the FB_AD[17:0] to SRAM_A[17:0],
FB_AD[15:0] to SRAM_D[15:0],
FB_RW to SRAM_WE#,
FB_ALE to the latched_FB_AD[17:0]
FB_CS0 to SRAM_CS0#?
Or do i any more glue logic? In the link above, the FB_AD[31:16] are used for data bus, but those pins are not available on the 64pin MK20DX64VLH7.
For this K20 device, the Fsys frequency is 36MHz. What could i expect as burst read/write rate? Considered the SRAM fast enough, are additional wait states required?
Any help or shared experiences with a multiplexed SRAM on the Kinetis would be helpful.
MS
Solved! Go to Solution.
Hi,
According to K20 product brief (page 25):
http://www.freescale.com/files/32bit/doc/prod_brief/K20PB.pdf
You can refer to AN4393 "Using FlexBus Interface for Kinetis Microcontrollers" Applicaction Note
http://cache.freescale.com/files/microcontrollers/doc/app_note/AN4393.pdf
It looks that latching in multiplexed mode as you wrote can work.
Hope this helps.
Hi, I am wondering the same thing.
The application note surely helps but does not show explicitly how to connect a 16bit(data bus) SRAM. I would REALLY appreciate to know exactly how to connect SRAM for maximum performance, preferably with a specific suggested SRAM device.
Thanks a ton!!
//bjoern
Michael,
how is it going? Was it helpful?
We'd like to know! :smileywink:
Regards!
Dear Monica,
thanks. First of all, i was impressed about the fast answer. And happy, that the answer was positive for my problem.
Actually, I have not implemented the details, so i dont know if the resulting hardware will work as expected. But i am positive for that.
best regards,
MS
Excellent Michael, we'll be around! :smileywink:
Hi,
According to K20 product brief (page 25):
http://www.freescale.com/files/32bit/doc/prod_brief/K20PB.pdf
You can refer to AN4393 "Using FlexBus Interface for Kinetis Microcontrollers" Applicaction Note
http://cache.freescale.com/files/microcontrollers/doc/app_note/AN4393.pdf
It looks that latching in multiplexed mode as you wrote can work.
Hope this helps.