NetBurner Community Forum

I would like to connect Everspin MR4A08B MRAM Memory to MOD54417 via FlexBus.
Memory is 8bit wide x 2MByte. So it has 8 data pins (D0..D7) and 21 address pins (A0..A20).
I understand that uP itself support this configuration. But I am not sure about module bus.
Is the module bus directly connected to uP bus pins, or it is latched some way?
From the module manual description the pins are named as A0..A15 and D16..D31.
(In contrast to FB_AD0 to FB_AD31 uP naming.)
Does it mean that A16 and above is not available on module and that maximum addressable space is 64k?
Or there is possibility to latch high address pins with hw buffer from D16..D31 pins?

For an 8 bit bus, data bus goes D31..D24
For a 16 bit bus D31..D16

By default the processor only brings out 64K worth of address.
You have two choices to fix this,
1)add a latch so you can write to a page register for the higher order bits.

2)Change the stuffing options on the MOD54415 there is a resistor jumper that will bring out the FB_ALE signal
out to the bus connector and you could use that to automatically latch the higher order address bits.
This change would require some minor rework on the 54415 , void the warenty etc...
IF you want more information on this submit a support request...