Electronic – Flashing of microcontrollers

Implement a USB-MIDI endpoint.

The Uno, with its secondary USB-capable MCU being used for serial communications by default, is not the best choice for this. Consider using a device with native USB support such as the Leonardo (ATmega32U4) instead.

It is 'just' DRAM, so you can interface it exactly like you would interface any other DRAM. Note though, that parallel DRAM is significantly more I/O intensive and very tough on simple microcontrollers as compared to SRAM. Also, 'computer' DRAM always has multiple packages of multiple banks of many pages, so you need to implement a bank/package aware driver. Otherwise you will only be able to address one of the chips (inside one of the packages).

As for timings: that's really easy. There is an i2c EEPROM on every bank that stores the timing data in a fairly straightforward manner (see the DDRx specification and search for SPD).

I would like to note, though, that although it's a cool little project, it wouldn't really be useful in a practical design. Computer DRAM is significantly more expensive to use and way overspecced for any microcontroller platform. An overview of the cost:

• DRAM socket ($2 in small quantities)
• Immensely large microcontroller ($15+ on top of whatever you have to get enough I/Os)
• Fast, fairly beefy 1.8V DC/DC converter ($2.50 for a switcher)
• Termination regulator ($1 for a Richtek part)
• quite a bit of board space for the module

If you really need gigabytes of RAM, this may be the only economical option. However, if you only need a couple (tens of) megabytes, there are some excellent PSRAM chips (e.g. https://octopart.com/is66wve4m16bll-70bli-issi-21833083) that work on (less than) 48 I/Os (i.e. small microcontroller package sizes), cost sub-$5, require almost no board space and still have ample performance for any microcontroller.