However I don’t see how that’s achievable over a serial connection. The maximum speed I was able to configure it is with a baud rate of 921600. I tried recompiling pppd to be able to set the baud rate at 1842000 and 3686400 (as reported by AT+IPR=?) but it seems to perform worse than 921600 (e.g. only one ping out of 3 comes back if the baud rate is 1842000 or 3686400 when it works reliably at 921600). I suspect some flow control issues, and since the HAT is not exposing hardware flow control pins there is now way to fix this.
The obvious solution is to switch to the USB interface, sadly it is not routed on this HAT.
Do you have any suggestions to achieve better speeds? Thanks!
Hi, I see you edited the product page to remove the uplink and downlink speeds. It would be even better to specify the maximum achievable speeds with the UART interface.
Can you recommend a way to reach the 10Mpbs/5Mbps speeds? What about the USB hack mentioned above?
Hi, no this is definitely a hardware issue. I did not try the USB hack suggested above since I did not spend the time to reverse engineer the board. Help from Pimoroni would be appreciated but I did not get any helpful replies here.
Hi, I’ve written to Pimoroni support, but I haven’t received any response yet. I found the schematic, and it shows that USB is broken out to some test pads. According to the SIMCom A7683E datasheet, it supports USB 2.0, but the pads aren’t labeled, so it’s down to trial and error at this point.