Hi,
I'm trying to get into the UART of the EX220 on baud 115200 8 databits 1 stopbit no parity no flow control but I just get some random gibberish spam.
I connected my serial cable through a level shifter. Without the level shifter it had the same result.
Does anyone have any ideas on what is going wrong?
Console output:
Wrong baudrate, you connected RX/TX the wrong way around, you didn't connect GND....
I tried every baud rate, I did connect ground. The router refuses to boot if RX/TX are switched
What level shifter?
You are supposed to use a TTL serial cable.
I used a USB - RS232 cable and connected the TX, RX and GND pins.
I measured the RS232 cable to have a voltage of 6V so I used a level shifter to get it down to 3.3v
RS232 is not the same thing. RS232 uses both positive and negative voltages for communications, TTL-level UART doesn't use negative voltages. RS232 also uses inverted levels for 1 and 0 compared to TTL UART. By using RS232 on the pins, you may have already fried your SoC.
That is not possible to measure like that since rs232 is differential voltage signals so that signal is free floating from ground and 15V between + and - cable.
Oh derp, I had RS232 cables because I manage a lot of enterprise switches/routers. Ordered a TTL cable. I'll update this thread in a couple of days when it arrived.
Thank you for the quick responses.
Been there done that😂
But my poor old wrt3200acm did survive😁
It was indeed just the cable.
I should probably open a new thread for this but I'm unable to have the router boot to OpenWRT
=> tftp openwrt.bin
Using eth@1e100000 device
TFTP from server 192.168.0.100; our IP address is 192.168.0.1
Filename 'openwrt.bin'.
Load address: 0x80010000
Loading: T #################################################################
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#
285.2 KiB/s
done
Bytes transferred = 4993135 (4c306f hex)
=> bootm 0x80010000
## Booting kernel from Legacy Image at 80010000 ...
Image Name: MIPS OpenWrt Linux-5.4.188
Image Type: MIPS Linux Kernel Image (lzma compressed)
Data Size: 4993071 Bytes = 4.8 MiB
Load Address: 80001000
Entry Point: 80001000
Verifying Checksum ... OK
Uncompressing Kernel Image ... lzma compressed: uncompress error 1
Must RESET board to recover
It's not listed as supported device, they are rather new. They also only ship to service providers as they have built-in remote management tools.
I see.
The LZMA error is pretty common, you can find several threads about it on the forum.
What compression was selected for kernel?
It actually looks like it's already running OpenWRT from the factory?
## Loading kernel from FIT Image at 80010000 ...
Using 'config@1' configuration
Trying 'kernel@1' kernel subimage
Description: MIPS OpenWrt Linux-4.4.198
Type: Kernel Image
Compression: lzma compressed
Data Start: 0x800100e4
Data Size: 3991654 Bytes = 3.8 MiB
Architecture: MIPS
OS: Linux
Load Address: 0x81001000
Entry Point: 0x81001000
Hash algo: crc32
Hash value: 0839e10e
Hash algo: sha1
Hash value: a344580f8713e7a72a272b8c58323d442f61a3b4
Verifying Hash Integrity ... crc32+ sha1+ OK
## Loading fdt from FIT Image at 80010000 ...
Using 'config@1' configuration
Trying 'fdt@1' fdt subimage
Description: MIPS OpenWrt EX221-G5V1 device tree blob
Type: Flat Device Tree
Compression: uncompressed
Data Start: 0x803dea88
Data Size: 10998 Bytes = 10.7 KiB
Architecture: MIPS
Hash algo: crc32
Hash value: 56e738e1
Hash algo: sha1
Probably just customized openwrt with their own firmware? Or is this just from me trying to get openwrt to run. It is booting tplink's firmware here.
They all are, or LEDE.
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