# Interfaces for the 180nm Oct2020 ASIC
+[[ls180]] actual interfaces
+
+[List Link](http://lists.libre-riscv.org/pipermail/libre-riscv-dev/2020-May/006355.html)
+
Bugreport and discussion at <https://bugs.libre-soc.org/show_bug.cgi?id=304>
These are bare minimum viability:
+These should be easily doable with LiteX.
* [[shakti/m_class/UART]]
* [[shakti/m_class/I2C]]
* [[shakti/m_class/QSPI]]
* [[shakti/m_class/LPC]]
* [[shakti/m_class/EINT]]
+* [[shakti/m_class/JTAG]]
+
+Under consideration:
+
+* [[shakti/m_class/sdram]] see <http://lists.libre-riscv.org/pipermail/libre-riscv-dev/2020-May/006374.html>
# Secondary priorities
-TODO
+* a pinmux
+* USB - again doable with LiteX. I'm talking to Enjoy Digital about what
+ USB PHYs LiteX supports. - Yehowshua
+* SERDES for Ethernet - using LiteX and
+ [Marvell PHY](https://www.mouser.com/ProductDetail/Marvell/88E1512-A0-NNP2I000?qs=vdi0iO8H4N0XzuXqBRxTqg%3D%3D)
+* Noting that a SERDES to RGMII PHY is $20 (kinda expensive for total cost
+ of an SBC), we can instead do Eth over USB like the original RPI. This
+ moves the complexity to software - could make doing eth things during
+ boot loader a little more complex.
+
+Jacob notes:
+
+I haven't checked but I'm 99% sure that we will need to implement standard
+Power atomics, fences, ll/sc (including 128-bit version), cache flushes,
+and non-cacheable load/store operations if we want to support Linux on our
+october test chip.
+
+<http://lists.libre-riscv.org/pipermail/libre-riscv-dev/2020-May/006407.html>
+
+## Alternate USB Interface Options
+ - https://github.com/im-tomu/valentyusb
+ - https://github.com/lambdaconcept/lambdaUSB
+ - https://github.com/greatscottgadgets/luna