BMC console com2 on Talos II

[twenex]

Hello, I've got one of these TTL/USB serial adapters that are suggested in the wiki and am
able to get output at 115200bps 8n1 which appears to boot up the BMC.  Unfortunately I don't seem
to be able to interrupt the boot process by "pressing any key" nor able to login.  I've tried setting
and unsetting software flow control to see if I can get any input.

The cable is pretty simple, TXD/RXD and GND.  I am not using the power lead (it shouldn't be necessary).

Is there something else I should be doing?

DRAM Init-V12-DDR4
0abc1-4Gb-Done
Read margin-DL:0.3470/DH:0.3470 CK (min:0.30)


U-Boot 2016.07 (Mar 17 2021 - 04:57:57 +0000)

       Watchdog enabled
DRAM:  496 MiB
Flash: 32 MiB
In:    serial
Out:   serial
Err:   serial
Net:   aspeednic#0
Hit any key to stop autoboot:  0
## Loading kernel from FIT Image at 20080000 ...
   Using 'conf@aspeed-bmc-opp-talos.dtb' configuration
...
[  OK  ] Started OpenBMC Software Update Manager.
[  OK  ] Started OpenPower Software Update Manager.
[  OK  ] Started Phosphor SNMP conf Manager.
[  OK  ] Started Phosphor Network Manager.
[  OK  ] Started Wait for /xyz/openbmc_project/state/chassis0.
[  OK  ] Started Phosphor Ldap config updater.
[   66.758448] ftgmac100 1e660000.ethernet eth0: Set package 0x0, channel 0x0 as preferred
[   66.769830] ftgmac100 1e660000.ethernet eth0: NCSI: No channel with link found, configuring channel 0

Phosphor OpenBMC (Phosphor OpenBMC Project Reference Distro) 0.1.0 talos ttyS4

talos login:

[MPC7500]

Hi, did you connect it to the internal header? Also pay attention to the correct pinout (DTK/Intel compatible)?

[twenex]

Yes, it is connected to the internal header on pints 3, 5 and 9 (gnd).

The part I have is from the Adafruit site which is linked on the page you've linked to.  But I'm willing to try another connector if these
do not really work.

Serial Adapters for BMC TTL Auxiliary Serial Header
Adafruit USB to TTL Serial Cable - Debug / Console Cable for Raspberry Pi [5]

[atomicdog]

Have you tried a different terminal program?

[twenex]

I'm trying with putty and teraterm.

I did check the J7701 pinout with the wiki concerning DTK/INTEL as I noticed the header had IC style numbering rather than as pin pairs.

3: RXD
5: TXD
9: GND

On the Adafruit USB to TTL serial the color scheme is:

BLK: GND
WHT: RX
GRN: TX

Red is for +5v which I do not have hooked up.

I also tried strapping CTS to RTS thinking they may need to be looped.

Right now, I just get output when BMC boots up, but I cannot input.  Reversing TX/RX makes the output look garbled.

Voltages on the J7701 header are all zero, except 3(RX) is -5.6, 4(RTS) 6.1+ and 7(DTR) 6.1+

[ClassicHasClass]

Just turn off flow-control entirely. You can get it working later.

[atomicdog]

PuTTY doesn't work with some devices because the line ending type is hard coded. You can change it in TeraTerm though, so I would try different setting for CR/LF in TeraTerm.

[twenex]

OK, flow control is off, and I'm using TeraTerm with CR+LF with transmit,
no luck.  I'm going to order another unit, as now that I think of it when it arrived it was
"open box" but I didn't think much of it at the time.

[atomicdog]

Sorry, I don't know if CR/LF is the correct setting, just meant you should try different ones.

You can also connect the TX and RX together on the dongle and see if you get what you type to loop back.

[twenex]

You're right, connecting TX to RX in loopback is simple enough to show that the USB adapter is working properly.
Meanwhile a second adapter arrived which was new and behaves the same way.  Basically, connect the adapter, open a TeraTerm session, apply mains power and watch it boot up.  Input from TeraTerm (with or without CR, CR/LF on transmit) isn't making it and when it gets to the Talos login: prompt input continues to not make it.

If I press the soft power after the BMC gets to the login: prompt the machine will attempt to IPL and display on the VGA port, but gets to a point where no progress is made.

I also have LAN1 on ethernet where it could DHCP, but I'm not seeing any requests.

[atomicdog]

There are a few issues. The connection should be RS232 not TTL. So you need a USB to RS232 adapter not USB to TTL.
I tried my USB/TTL and got the same result you did. So, I checked the schematic and noticed it shouldn't be TTL and also the pinout in the schematic is different from the manual.

In the manual pin numbers alternate rows. So, ground is the bottom right most pin9 (pin 5 in schematic).

[ClassicHasClass]

For the record, this is how mine is hooked up: basically one of those 10 pin to DE-9 headers, and then a regular USB serial connector. https://www.talospace.com/2020/04/what-to-do-when-bmc-wont-talk-to-you.html

[MPC7500]

I have the DIGITUS AK-610300-003-E. But until today I haven't needed it yet.

[twenex]

Wow, OK so I hope that for others this thread helps to understand type of cable and connection needed for COM2 J7701 on the Talos II board.

* It is not TTL and following the manual pinout and using a TTL/USB might give you false hope
* Pin out is incorrect

It is DTK/INTEL DB9M to IDC10 which is part number 07121 from pccables.com
Use with a RS232 serial cable with a null modem.

Thanks!

After that I was able to interrupt the boot and can poke around.  Unfortunately it does look like the BMC root password is no longer 0penBmc though, so that will be the next step for me.

https://wiki.raptorcs.com/wiki/BMC_Default_Password

I do not have the slip of paper. 

[MPC7500]

Why don't you have the paper with the password? It's in the mainboard box. Is the Talos used? If yes, I would ask the seller.