tag:blogger.com,1999:blog-5768610196044632406.post5448890444928630145..comments2024-01-07T16:20:36.838+00:00Comments on Steven's Blog: MTK (Mediatek) debug cablestevenhoneymanhttp://www.blogger.com/profile/06494159684713841991noreply@blogger.comBlogger17125tag:blogger.com,1999:blog-5768610196044632406.post-47802250128090620182017-02-21T18:13:32.497+00:002017-02-21T18:13:32.497+00:00I wouldn't recommend it (although I have done ...I wouldn't recommend it (although I have done in the past without causing any noticable damage). The datasheet says 1.7-1.9v as the absolute max rating.<br /><br />You can make a level shifter with just a few parts, or buy them for a few cents/pence on ebay. This kind of thing will work fine for UART/JTAG/etc: https://learn.sparkfun.com/tutorials/bi-directional-logic-level-converter-hookup-guidestevenhoneymanhttps://www.blogger.com/profile/06494159684713841991noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-54702553678267950952017-02-21T07:00:38.235+00:002017-02-21T07:00:38.235+00:00I've finally managed to get systemd to work (e...I've finally managed to get systemd to work (even though I used kernel for other MTK6589 SP). One last question: is it OK if I also connect RX pin (1.8V) to my USB-TTL (3.3V)?<br />Thank you for everything.tmp64https://www.blogger.com/profile/18087145371467789624noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-55169782139457681232017-02-20T06:31:20.403+00:002017-02-20T06:31:20.403+00:00Ah well, I'm glad you got it working!Ah well, I'm glad you got it working!stevenhoneymanhttps://www.blogger.com/profile/06494159684713841991noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-18935115640562024422017-02-20T02:29:31.548+00:002017-02-20T02:29:31.548+00:00Fixed it with the orange loop. It was the interfer...Fixed it with the orange loop. It was the interference.<br />http://imgur.com/a/8Xljhtmp64https://www.blogger.com/profile/18087145371467789624noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-75419358426184458002017-02-19T14:44:52.454+00:002017-02-19T14:44:52.454+00:00It's probably not interference at the low spee...It's probably not interference at the low speeds that UART runs at. Do you have any kind of oscilloscope or logic analyzer? That'd be the easiest way to see what's actually being transmitted.stevenhoneymanhttps://www.blogger.com/profile/06494159684713841991noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-6708705936426586452017-02-19T13:54:16.779+00:002017-02-19T13:54:16.779+00:00I tried different baudrates (921600 too), but I ha...I tried different baudrates (921600 too), but I had the same result: garbage instead of text. Is it possible that my thin wires cause interference :) ?<br />By the way, thanks for quick reply.tmp64https://www.blogger.com/profile/18087145371467789624noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-77423304432182731912017-02-19T13:30:04.015+00:002017-02-19T13:30:04.015+00:00Looks like a wrong baud rate setting. The MTK defa...Looks like a wrong baud rate setting. The MTK default is 921600.stevenhoneymanhttps://www.blogger.com/profile/06494159684713841991noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-11880332972157564472017-02-19T13:21:44.717+00:002017-02-19T13:21:44.717+00:00Hello again. I've connected UTXD4 to my PL2303...Hello again. I've connected UTXD4 to my PL2303HX (only GND and RX). I get come output to the console, but I think the charset is wrong (I use UTF-8): http://imgur.com/VSK9L0a . Do you have any ideas?tmp64https://www.blogger.com/profile/18087145371467789624noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-75132525093406183622016-12-28T15:59:09.514+00:002016-12-28T15:59:09.514+00:00I was wrong, actually. I checked it with a multime...I was wrong, actually. I checked it with a multimeter and it's 3.3V. But it didn't work anyway.<br /><br />I tried modifying the LK to have printk.disable_uart always 1, but it didn't work. Swapping the RX and TX lines didn't help either. And there's no UART on the motherboard, no kernel sources for the phone. And the LCD screen is dead too.<br /><br />I needed the UART to try to install Debian instead of Android.tmp64https://www.blogger.com/profile/18087145371467789624noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-83102704562965775362016-12-28T12:23:51.262+00:002016-12-28T12:23:51.262+00:00If it's definitely using 5V I/O then yes, prob...If it's definitely using 5V I/O then yes, probably. The Mediatek data brief lists the absolute maximum rating for the USB to be 3.465V<br /><br />However the datasheet for the PL2303HX (rev D) says the serial signals are limited from 1.8V to 3.3V... not as far as 5V. http://www.prolific.com.tw/userfiles/files/ds_pl2303hxd_v1_4_4.pdf<br />(page 13, pin 4)stevenhoneymanhttps://www.blogger.com/profile/06494159684713841991noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-7653295194905945082016-12-28T11:39:57.392+00:002016-12-28T11:39:57.392+00:00So, my 5V USB-TTL PL2303HX might have killed the U...So, my 5V USB-TTL PL2303HX might have killed the UART in my old phone :)tmp64https://www.blogger.com/profile/18087145371467789624noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-16719885114506636872016-12-28T07:36:43.113+00:002016-12-28T07:36:43.113+00:003.3V on the SoCs I've tested - the same as USB...3.3V on the SoCs I've tested - the same as USB FS ( https://en.wikipedia.org/wiki/USB#Signaling )stevenhoneymanhttps://www.blogger.com/profile/06494159684713841991noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-2039366799043849832016-12-28T06:48:13.776+00:002016-12-28T06:48:13.776+00:00Does it use 5V or 3.3V data voltage levels?Does it use 5V or 3.3V data voltage levels?tmp64https://www.blogger.com/profile/18087145371467789624noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-60745338413153861462016-08-19T21:13:31.404+01:002016-08-19T21:13:31.404+01:00This does not work on my Honor 3C (H30-U10). There...This does not work on my Honor 3C (H30-U10). There's no output produced. I tried swapping TX/RX, no success. And yes baud rate was set to 921600.Anonymoushttps://www.blogger.com/profile/08964000087838975960noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-1915163218263806802016-06-18T15:07:59.483+01:002016-06-18T15:07:59.483+01:00It just needs to be plugged in while the phone is ...It just needs to be plugged in while the phone is switched off. This starts producing output from the preloader, and keeps running through lk, but most likely output will stop once the kernel starts - the default boot cmdline includes a printk.disable_uart=1<br /><br />You can either patch this in lk, or there is an undocumented fastboot command to toggle it for the next reboot. I can't quite remember what it was, but something along the lines of "fastboot oem p2u 1"<br /><br />You should still see hundreds of lines of output before the kernel loads though, so if you've got nothing then maybe your tx/rx are swapped, or baud rate is incorrect?stevenhoneymanhttps://www.blogger.com/profile/06494159684713841991noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-43702838148880158032016-06-18T11:51:06.438+01:002016-06-18T11:51:06.438+01:00Is there anything needed in terms of kernel settin...Is there anything needed in terms of kernel settings? I can't get this to work on either fairphone1 nor Wiko Stairway.<br /><br />Is there a specific boot up sequence needed? Like plugin cable when battery out?Unknownhttps://www.blogger.com/profile/04884035781441873870noreply@blogger.comtag:blogger.com,1999:blog-5768610196044632406.post-54706533148807469582015-02-24T14:48:41.198+00:002015-02-24T14:48:41.198+00:00hey, that's what i'm looking for :)hey, that's what i'm looking for :)Anonymoushttps://www.blogger.com/profile/06997375954439802039noreply@blogger.com