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xmos / lib_sdram

SDRAM library
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SDRAM Startup sequence contains errors #12

Closed ed-xmos closed 7 years ago

ed-xmos commented 8 years ago

STartup code initially has CAS/RAS/WE set low. This is LOAD MODE REGISTER - it should start up in NOP (command inhibit not supported as CE permanently enabled). There are few problems with timing as well. This seemed to work on ISSI parts but failed on MT48LC16M16A2P resulting in device not responding to commands.

Updated code that does work on Micron and ISSI:

https://github.com/ed-xmos/lib_sdram/commit/f4b6821b427cf33ad5af66161bd7b9c8708ab00d

ed-xmos commented 7 years ago

Addressed by 3.2.0 / https://github.com/xmos/lib_sdram/pull/18