JTAG debugging at 1.8v

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hassan789
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JTAG debugging at 1.8v

Postby hassan789 » Thu Jan 04, 2018 9:21 pm

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?

ESP_igrr
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Re: JTAG debugging at 1.8v

Postby ESP_igrr » Thu Jan 04, 2018 9:45 pm

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.

Daniel
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Joined: Tue Jan 09, 2018 12:55 pm

Re: JTAG debugging at 1.8v

Postby Daniel » Thu Jan 11, 2018 2:30 am

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.

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hassan789
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Re: JTAG debugging at 1.8v

Postby hassan789 » Sat Jan 13, 2018 5:47 am

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!
Attachments
domain.jpg
domain.jpg (80.28 KiB) Viewed 886 times
rtc.JPG
rtc.JPG (129.84 KiB) Viewed 887 times

ESP_igrr
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Re: JTAG debugging at 1.8v

Postby ESP_igrr » Sat Jan 13, 2018 9:47 am

Oh, apparently I was reading an older version of the datasheet. Sorry for the confusion.

ESP_Sprite
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Re: JTAG debugging at 1.8v

Postby ESP_Sprite » Sun Jan 14, 2018 2:22 am

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.

sudee.as
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Re: JTAG debugging at 1.8v

Postby sudee.as » Sun Jan 14, 2018 5:34 am

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.

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hassan789
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Re: JTAG debugging at 1.8v

Postby hassan789 » Wed Jan 17, 2018 5:08 pm

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.

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