[seL4] Re: sel4 on bare-metal | Questions and comments

Hi Peter, Thanks, for the explanation. Shall we add this to PC99 https://docs.sel4.systems/Hardware/IA32 site? Could potentially save people a lot of time :) Sid On Thu, Jun 9, 2022 at 4:01 PM Peter Chubb wrote:

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"Sid" == Sid Agrawal writes:

Sid> An update for the archives. Desktop: ----------- I tried doing Sid> the same experiment Peter suggested - i.e., try from Linux to Sid> check if the serial port worked fine. But I was still getting Sid> garbled data, I played with baud, parity, stop bits, etc., but no Sid> luck. The serial to USB cables I tried was:

Desktops/servers etc., use the RS232 standard for their serial ports. Embedded X86 boards can use RS232 or RS422, or occasionally other standards. These use ą12V levels, referenced to ground for RS232, and floating in pairs for RS422.

The embedded development boards we use bring out the UART pins directly, without an RS232 or RS422 driver, so they are at whatever voltage the UART chip runs at, using gound as a reference. Usually, that's 1.8V, 3.3V or 5V. Your typical FTDI cable will talk one of these.

Peter C -- Dr Peter Chubb https://trustworthy.systems/ Trustworthy Systems Group CSE, UNSW Core hours: Mon 8am-3pm; Wed: 8am-5pm; Fri 8am-12pm.