Activity
From 06/16/2024 to 07/15/2024
07/03/2024
- JC 02:19 PM Software Development: RE: MityDSP-L138 Power Draw in Deep Sleep? Waking ARM core from DSP core? Power and Sleep Controller (PSC)
- Michael Bisbano wrote in message#6697:
> Hi Jonathan,
> ...
We have some posted power usage measurements for the module here: https://support.criticallink.com/redmine/projects/arm9-platforms/wiki/33V_Supply_Requirements
A max of 1W l...
07/01/2024
- MB 09:16 PM Software Development: RE: MityDSP-L138 Power Draw in Deep Sleep? Waking ARM core from DSP core? Power and Sleep Controller (PSC)
- Hi Jonathan,
Thank you for the response, please let me know what you find out! The system as a whole must be under 1W average while operating, and very low <50mW when in sleep. When operating, it will be performing some audio signal pr... - JC 07:05 PM Software Development: RE: MityDSP-L138 Power Draw in Deep Sleep? Waking ARM core from DSP core? Power and Sleep Controller (PSC)
- Michael Bisbano wrote:
> Hi all,
> ...
Hi Michael, I did a bunch of work for the MitySOM-335x for sleep mode but am not sure about the L138. I'll ask around and let you know what I find out.
>
> ...
In the meantime could you clarif... - Hi all,
I was wondering if anyone had data on power draw for the MityDSP-L138 in deep sleep? My application is battery powered and we are determining if it is more feasible to have an external circuit on our custom baseboard control p... - JC 03:49 PM Software Development: RE: Serial port 2 issue, RS485, RTS drops to early
- Fred Weiser wrote in message#6688:
> Changing the timer is probably not in my best interest; my project supports down to 1200 baud with packets up to 256 in length (that's over 2 seconds). I see two possibilities:
Can you try it just t...
06/27/2024
- FW 09:06 PM Software Development: RE: Serial port 2 issue, RS485, RTS drops to early
- Changing the timer is probably not in my best interest; my project supports down to 1200 baud with packets up to 256 in length (that's over 2 seconds). I see two possibilities:
# Add RTS/CTS back into the pinmux, disable the 485 confi... - FW 06:12 PM Software Development: RE: Serial port 2 issue, RS485, RTS drops to early
- Here's the snip:
- JC 05:45 PM Software Development: RE: Serial port 2 issue, RS485, RTS drops to early
- Looks like wait_for_xmitr has a 10ms timeout, this might explain why the TXEN is enabled for a constant time. At low baud rates the 10ms timeout would be more of an issue I suspect.
Note in newer kernels, the stop_tx call checks the ... - JC 04:19 PM Software Development: RE: Serial port 2 issue, RS485, RTS drops to early
- What does your pinmux look like for UART2?
- FW 03:36 PM Software Development: RE: Serial port 2 issue, RS485, RTS drops to early
- Please see two attached scope traces; the second with a 7 character buffer, the first with a 16 character buffer. I wanted to provide some objective evidence to your comments above... Notice the RTS active time is the same; it is that wa...
- TI 02:31 PM Software Development: RE: Serial port 2 issue, RS485, RTS drops to early
- It looks like (in the 3.2 kernel anyway) the only serial port driver that supports the delay_rts_after_send option is the atmel_serial.c, and it uses features of the UART to implement it.
You could implement this in the 8250 driver and ... - FW 01:46 PM Software Development: RE: Serial port 2 issue, RS485, RTS drops to early
- Thanks for the ideas; I'm looking into the code cited above now; I don't have any new news there at this time.
However, here is some additional info: when the RTS line drops early, it may be a partial character, or sometimes as many ... - TI 01:05 PM Software Development: RE: Serial port 2 issue, RS485, RTS drops to early
- My suspicion is that the register read in wait_for_xmitr() is "lying" and the UART is actually still serializing the data even though it says the TSR is empty.
My suggestion is to put a delay of 1 char before releasing the GPIO. This co... - JC 08:47 PM Software Development: RE: RS485 Direction Control on UART1
- Seems like it could work. Good find.
- MB 07:17 PM Software Development: RE: RS485 Direction Control on UART1
- I did come across this application note from TI: https://www.ti.com/lit/ug/tidubw6/tidubw6.pdf?ts=1719509747706
(if the link is broken in the future to others with this need, the article is titled: "TIDUBW6 - June 2016: TI Designs Autom...
06/25/2024
- JC 09:59 PM Software Development: RE: Serial port 2 issue, RS485, RTS drops to early
- The kernel driver code for RS485 support can be found here: https://support.criticallink.com/gitweb/?p=linux-davinci.git;a=blobdiff;f=drivers/tty/serial/8250.c;h=fd19e7d82137f1bcccae36b6cade7878267fc8f9;hp=eeadf1b8e093202234b30c688490da2...
- FW 06:58 PM Software Development: RE: Serial port 2 issue, RS485, RTS drops to early
- Seems a "paste" didn't work as expected...
SER_RS485_USE_GPIO is the same as 1<<5 - We are having a problem with serial port ttyS2 on our L138 SoM which I believe resides in the Linux driver or the TI serial port support. The port is used as a RS-485 interface running Modbus, which requires using the RTS line to control...
06/20/2024
- JC 07:57 PM Software Development: RE: RS485 Direction Control on UART1
- How long are you looking for?
The kernel documentation mentions getting extended distance for rs232 by using UTP cat 5 cable. Or using a shield low-capacitance wire. Also mentions using line drivers to get larger distances.
https://... - MB 03:43 PM Software Development: RE: RS485 Direction Control on UART1
- Hi Jonathan,
thanks for the quick response. I will look into the 8250 driver, it might be useful (if only for my runtime code). I expected a hesitant response with regard to this scheme, but half duplex RS485 is unfortunately the mos...
06/19/2024
- JC 07:09 PM Software Development: RE: RS485 Direction Control on UART1
- The serial 8250 driver has an rs485 mode which we extended to allow using a gpio to generate a RS485 TX enable. However this was intended to be setup at runtime for a separate interface and not for the debug console. Though you may be ...
- Hi all,
My application requires installation embedded in a battery power system with long wire. I would like access to UART1 over the wire, which we have decided to use half duplex RS-485 for. Is there a way to make the UART1 integrat...