Hi All
The new M5225X family have a reduced FlexBus supporting 2 Chip Selects. By configuring ports TE, TF, TG and TH to FlexBus mode it is possible to address up to 1Meg of 8 bit external memory (or other peripherals). The bus is fast, allowing 12.5ns* cycles with 80MHz PLL (which can be matched to the memory/peripherals using additional wait states). [*12.5ns at 80MHz in 1:1 mode or 25ns in 1:2 mode as controlled by MBMOD in the Chip Configuration Extended register]
The M52259EVB is delivered with an MRAM chip on-board (MR2A16ACYS35). This is a 256k magnetoresistive random access memory with read and write times of just 35ns, compatible with 35ns SRAM. It is made by EVERSPIN TECHNOLOGIES, to whom Freescale has transferred this technology to. It retains data for 20 years, has no wear-out and can replace SRAM and FLASH. Of course it is more expensive that FLASH but there are certainly applications where type of device is perfect - it is essentially FLASH with the ease and speed of SRAM (a modern bubble-memory may be the correct description..(?)).
So it was time to try out the FlexBus - and the MRAM was predestined. After learning some details about the FlexBus configuration I managed to add a set up to the M5223X project which operates the uFileSystem from MRAM. In addition I could confirm that the transfers to and from the MRAM via FlexBus works correctly using DMA.
This configuration will thus be included in the forthcoming SP9 to the M5223X project, including the new M5225X support. I believe that the DEMO and EVB boards will not be delivered for a couple of weeks so I prefer to continue experimenting with the new capabilities of the device so that the SP release will include as much new stuff as possible. If you do receive a board before expected just tell me so that the SP can be made ready to go. Note that you will not have MRAM on the DEMO board - it is only on the EVB.
Regards
Mark