Does anyone know of a DDR stress test for Coldfire?
I am looking for something like this:
i.MX6/7 DDR Stress Test Tool V2.60
I haven't seen anything.
Which Coldfire chip are you using?
The i.MX DDR controllers are very complicated and have 64 32-byte registers that need to be set up "properly" for the 400MHz DDR3 bus to operate reliably. The timing is very fussy, as is the PCB layout. There's a lot of "calibration cycles" that need to be run, either "all the time" or once using the "Stress Test" to get the best numbers for your board and chips to pre-load into the huge number of registers.
The (much) older ColdFire chips like the MCF5235 only have to worry about simpler and slower SDRAM, usually running at 80MHz or less, The controller only has 5 bits plus an 8-bit counter in one control register and 10 bits in another control register to set up. There's a lot less to get wrong, and most numbers are simply lifted from the SDRAM data sheet.
The MCF5329 has a controller than can handle CSR or DDR, but only up to 80MHz. There are only three registers that need configuring to match it up with the RAM chip.
The MCF547x and MCF54455 controllers are the same, except they can run up to 133MHz.
That's not to say the RAM can't go wrong. Here's one thing you can get badly wrong with it:
Or this one:
Or you might want to start here for other problems:
Thanks Tom, the pad settings discussions you linked to are worth investigating.
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