Bitstream loading through BL616 on Nano 20K

nand2mario / nestang

NESTang is an FPGA Nintendo Entertainment System implemented with Sipeed Tang Primer 25K, Nano 20K and Primer 20K boards

https://nand2mario.github.io/nestang

GNU General Public License v3.0

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Bitstream loading through BL616 on Nano 20K #7

Open nand2mario opened 1 year ago

nand2mario commented 1 year ago

In theory, BL616 can read bitstream from SD card or USB and program the FPGA, allowing switching between cores.

Some discussion here: https://www.reddit.com/r/GowinFPGA/comments/11u5vlf/usb_cdcserial_repl_for_pikapython/

Issues:

The BL616 doesn't have enough memory to hold the whole fs image (8MB).
BL616 is wired as a USB device (CC pins tied to ground). So it cannot act as a USB host even if the sdk allows it.

harbaum commented 9 months ago

The BL616 can act as a USB host. See https://www.youtube.com/shorts/bP5gK3nmv-o

harbaum commented 9 months ago

The fs image is only ~700k. The .fs files are ASCII and thus way bigger. But 700k is still too much for the BL616. I am considering using an external SPIU or I²C RAM.