We have a RS-485 interface being driven by UART2 on the Orin module. The JetPack OS sees this as “/dev/ttyS0”. The UART2/RTS signal runs to the DE pin of a MAX22500 level shifter. The DE pin enables the outputs when high and High-Z the outputs when low. Unfortunately, the way JetPack/UART2/RTS is co…

Sorry, to enable bit 3 (start from 0), you should write 0x8. $ sudo busybox devmem 0x03140020 w 0x8 $ sudo busybox devmem 0x03140020

Hi mt_developer, Are you using the devkit or custom board for AGX Orin? Could you share the block diagram of your connections? [image] mt_developer: the way JetPack/UART2/RTS is configured, the UART2/RTS sits high and is driven low only when we write data to RS-485@ttyS0. It seems the expe…

[image] KevinFFF: Are you using the devkit or custom board for AGX Orin? We are using a custom board developed by our consultant (so not an in-house design). [image] KevinFFF: Could you share the block diagram of your connections? I have uploaded the MAX22500e part of the schematic. T…

As my ubderstanding, RTS/CTS are used for HW flow control of UART communication. RTS will be asserted (pulled low) when it is ready to send data and will be deasserted (pulled high) when it finishes the transmission. For DE(Driver Enable), it seems HIGH to allow data transaction and LOW to disable…

I apologize if what follows seems confusing, I’m using analogies to Ethernet… I haven’t had to deal with RS-485, but it has a lot in common with RS-232. On RS-232, when directly connecting one UART to another without the intermediate data device, one would connect the first TX to the second RX, and…

If you read my quote or followed the Advantech link from my previous post, you would have seen that the story from Advantech and my quoted text (from the same story), states the exact opposite. I have requoted the story and reposted the link. Can you address the specific statement from Advantech con…

Yes, I know that you want to invert the behavior of RTS for your RS-485. I’m asking for your dmesg to confirm which UART interface is in use and will suggest you how to do that. PLEASE share the full dmesg for further check.

I have attached the dmesg log. This is the command I used to capture this [sudo dmesg > dmesg.log]. If this is not what you want/need please tell me exactly how to retrieve what you do want/need. dmesg.log (55.7 KB) Thanks, Bob

Here you go … fc-dev@jetsonorinotto:~$ sudo busybox devmem 0x03140020 0x00000000 fc-dev@jetsonorinotto:~$ sudo busybox devmem 0x03140020 32 4 fc-dev@jetsonorinotto:~$ sudo busybox devmem 0x03140020 0x00000004 It looks like that bit can be flipped, so that’s good. I will have to (re)setup the R…

Okay, please let us know if it could invert the behavior of RTS.

Need to Invert UART2 RTS

Robotics & Edge Computing Jetson Systems Jetson AGX Orin

KevinFFF September 2, 2024, 6:43am 11

[    6.279043] 3140000.serial: ttyS0 at MMIO 0x3140000 (irq = 113, base_baud = 4250000) is a Tegra

Okay, it seems you are using serial@3140000 currently.

Please share the result of the following command on your board.

$ sudo busybox devmem 0x03140020

It is the register of UART_IRDA_CSR_0 of UARTE.
The bit 3 is INVERT_RTS.
Please try to enable it to check if it can help for your case.

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Need to Invert UART2 RTS

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