I've ended up talking to a few people recently about LEDs.
CE and EE have four user lights which are often hooked up in different
ways on each board.
Are there any common recommendations about default LED hook ups for the
kernel (e.g. USR1 -> heartbeat, USR2 -> disk I/O, etc)?
Similarly it might be useful to have a couple of events nominated where
we recommend a firmware level bootloader change LED status. Some
- Set USR1 on when bootloader starts up (a NOR/eMMC/SD is not empty
- Set USR3 on when entering fastboot mode (if supported)
- Set USR3 off when leaving fastboot mode, including via "fastboot
boot" (if supported)
- Set USR1 off and USR2, 3 and 4 on if bootloader panics.
Especially for CE board (where users often don't have a UART adapter)
even the above simple hints that the bootloader has been fetched from
somewhere is useful.
I know this can't be a rule, only "good advice" (like asking CE boards
to put console on LS-UART1 if possible). However, is there any appetite
to converge for the boards we have influence over?
 Here I definitely mean EDK2 rather than grub. If we have multiple
chained firmware level bootloaders (e.g. LK -> u-boot) things are
less clear although, as it happens, if *both* implemented the above
proposal the results would still be perfectly useable from a user
(cc'ing the appropriate 96boards dev list)
On Sun, Jun 18, 2017 at 5:11 PM, Robert P. J. Day <rpjday(a)crashcourse.ca> wrote:
> not sure if this is the right list to point out oddities in the
> documentation, but i'm reading this:
> and in the ToC, under "Low Speed Expansion Connector", there is no
> mention of I2S, but in the very next section, "Introduction", under
Actually, it says PCM/I2S, just like the specification.
> "I/O Interfaces", one reads:
> One 40-pin Low Speed (LS) expansion connector
> UART, SPI, I2S, I2C x2, GPIO x12, DC power
> should I2S be added to the ToC for consistency? or am i misreading
As per the spec, the LS connector must expose I2S/PCM. In other words,
PCM data over I2S interface. In the pinout for the LS connector, the
signals are named as PCM_FS, PCM_CLK, PCM_DO and PCM_DI on pins 16,
18, 20 and 22 respectively.
The text under the introduction could be fixed to say I2S/PCM to be
consistent with other parts of the documentation including the
Want to submit a patch to the documentation? :-)