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JTAG debugging at 1.8v

Posted: Thu Jan 04, 2018 9:21 pm
by hassan789
I am running my ESP32-D2WD at 1.8v
Looks like the FT2232H chip does not support 1.8v JTAG debugging.

Any recommendations for debugging the chip at 1.8v?

Thanks :)

EDIT:
Looks like the Flyswatter2 supports 1.8v, must have level sifters inside?

Re: JTAG debugging at 1.8v

Posted: Thu Jan 04, 2018 9:45 pm
by ESP_igrr
Like other variants of ESP32, ESP32D2WD is rated for supply voltages down to 2.3V.
Only the pins in VDDSDIO power domain of the ESP32D2WD work at 1.8V, the rest of the pins work at 2.3-3.6V.
JTAG pins are not in VDDSDIO power domain, so your JTAG adapter does not need to be 1.8V compatible.

Re: JTAG debugging at 1.8v

Posted: Thu Jan 11, 2018 2:30 am
by Daniel
dear hassan789,@ hassan789 I want to use the ESP32-D2WD, but it seems that my PCB has problem.so I was burning to know how the circuit diagram you make ? Would you give me a reply ?Thanks very much.
Best wishes .Daniel.

Re: JTAG debugging at 1.8v

Posted: Sat Jan 13, 2018 5:47 am
by hassan789
ESP_igrr wrote:Like other variants of ESP32, ESP32D2WD is rated for supply voltages down to 2.3V.
Only the pins in VDDSDIO power domain of the ESP32D2WD work at 1.8V, the rest of the pins work at 2.3-3.6V.
JTAG pins are not in VDDSDIO power domain, so your JTAG adapter does not need to be 1.8V compatible.
igrr,
According to the latest ESP32 datasheet, both VDD3P3_CPU & VDD3P3_RTC can be power from 1.8v to 3.6. See attached..
Since the JTAG lines are in RTC domain, they should be 1.8v, if my understanding is correct. I am designing a board with all domains powered at 1.8v (except VDDA at 3.3v). Please Advise!

Re: JTAG debugging at 1.8v

Posted: Sat Jan 13, 2018 9:47 am
by ESP_igrr
Oh, apparently I was reading an older version of the datasheet. Sorry for the confusion.

Re: JTAG debugging at 1.8v

Posted: Sun Jan 14, 2018 2:22 am
by ESP_Sprite
FYI, a fair few other boards like the TUMPA also have level shifters inside. If you don't have one, maybe you can hack something up with a SN74LVC16T245 or a discrete set of resistive dividers on tck/tdo/tms plus a comparator on tdi.

Re: JTAG debugging at 1.8v

Posted: Sun Jan 14, 2018 5:34 am
by sudee.as
since i am successful in jtag debug the eps32 wrover with open ocd , change the voltage value in esp32_xxx.cfg file to 1.8V , try.

Re: JTAG debugging at 1.8v

Posted: Wed Jan 17, 2018 5:08 pm
by hassan789
looks like the problem with flyswatter2 is that the UART is 12v...
the TIAO USB Multi-Protocol Adapter (TUMA) claims to be 1.8v JTAG compliant, but the UART is either 3.3v TTL or 12v RS-232.