Date: Tue, 14 Jan 2025 22:37:28 +0000 From: bugzilla-noreply@freebsd.org To: usb@FreeBSD.org Subject: [Bug 284042] FTDI: UART breaks JTAG Message-ID: <bug-284042-19105-uK8mdZgYCj@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-284042-19105@https.bugs.freebsd.org/bugzilla/> References: <bug-284042-19105@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D284042 --- Comment #7 from Tomasz "CeDeROM" CEDRO <tomek@cedro.info> --- Very cool that modern uftdi can disable JATG port not to be grabbed by ucom= it was not there back then. From my initial report it seems it was working as = ucom then jtag then ucom then jtag.. so probably a bug in uftdi / ucom :-( Accor= ding to FT2232H datasheet it is possible to configure two channels independently= so one works as UART and the other one works as MPSSE in theory they should not disturb each other. https://ftdichip.com/wp-content/uploads/2024/09/DS_FT2232H.pdf Regarding USB-Serial-JTAG the ESP32-C3 and ESP-C6 (RISC-V CPU) indeed has s= ome minimalistic implementation. But if you look at ESP32-S3 TRM Chapter 33 Page 1247: > The CPU JTAG signals can be routed to the USB Serial/JTAG Controller or e= xternal GPIO pads using eFuses > and when the user program has started, software control as well. At that = time, the JTAG signals from the USB > Serial/JTAG can also be routed to the GPIO matrix. This allows debugging = a secondary SoC via JTAG using the > ESP32-S3 USB Serial/JTAG Controller. It would not be RISC-V CPU but the probe can be built that way utilizing ES= P's JTAG Command Processor. What is more both channels use CDC-ACM so it should= be also possible to expose this simple serial transport over BLE or WIFI. Wish= I had time to play around with it. Unfortunately I could not find anyone interested in funding this kind of research. Maybe you can make it happen := -) https://www.espressif.com/sites/default/files/documentation/esp32-s3_techni= cal_reference_manual_en.pdf --=20 You are receiving this mail because: You are the assignee for the bug.=
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