Hi Daniel, I have discovered a problem with the M.2 Key B slot of the BPI-R4. The 32 kHz CLKOUT signal of the RTC is (according to the specs) connected to PIN 68.
However, on all the m.2 WWAN modules I have tested, this PIN is either not connected or is even used for a different function. For example, the Telit MV32-W-A (aka Foxconn T99W368) is not working until I disable the CLKOUT of the rtc. This module uses PIN 68 to enable write-protection of the internal flash. (so, a 32kHz signal on this pin isn't really a good idea) Unfortunately, it happens from time to time that I still can't start after disabling CLKOUT and the module has to be reset completely. My idea for a workaround would be to deactivate the CLKOUT of the RTC in the uboot (possibly using a preboot command) as soon as possible after power-on. However, this would also deactivate the signal at the M.2 Key M slot and I don't know whether it is actually needed there. Alternatively, only a hardware modification with removal of R62 would remain. What's your opinion? Regards, Martin _______________________________________________ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/mailman/listinfo/openwrt-devel
