CIRCLE WITH A DOT

@whitequark in theory you can use openocd to wake it up and switch it to 4 wire mode but thats also not very fun;

in the TI parts the GPIO mux is subordinate to the JTAG TAP so if you wake up 4 wire mode it takes over the other two pins no matter what the GPIO mux is set to afaict

@whitequark yeah it's a PITA I was trying to bring up a CC1354 and just could not get it to respond

@whitequark if the REd schematic is to believed TCKC goes only to a testpoint

@whitequark yup i only mention because TMSC (GPIO11) and TCKC (GPIO10) both go straight to vias (and then maybe to the array of testpoints on the back?); Wheras TDO (GPIO9) seems to go to the flash and TDI (GPIO8) seems to go ??.

So I was thinking there's a chance they might be explicitly configuring it as cJTAG and using it for a boundary scan test after manufacture.

@whitequark could it have booted in cJTAG mode?

@artemist @whitequark ️IP

@whitequark @gsuberland @ftg cursed thought: pentium based ECU

@whitequark @gsuberland @ftg maybe its a rebranded automotive part

@whitequark @gsuberland @ftg from what i understand one of the big selling points of ARC is that they let you add ~whatever instructions you want and they make it relatively easy to use those instructions from C, so that might be whats going on there?

@azonenberg @ftg @whitequark @gsuberland Yes the Genesys 2 has this; it's very funny (but makes sense in an education setting if you want to keep your PS2 mouse lab without keeping the mouses)

@gsuberland @ftg @whitequark looks like yes

@gsuberland @ftg @whitequark did they ever ship non-es silicon for the propeller 2

@gsuberland @ftg @whitequark its at least less unhinged than the hard microblazes that show up in a bunch of xilinx parts

@whitequark @gsuberland @ftg excuse me thats where 8051s are supposed to live; thats an invasive species

@gsuberland @ftg @whitequark It's also pretty common inside memory controllers afaict (the STM32MP2 and some RKs that use Synopsys DDR IP use it). I would be surprised if its not embedded in a lot of Synopsys IP

@Rairii @gsuberland @ftg @whitequark a lot of modern problems can probably be blamed on starfox

@gsuberland @ftg @whitequark This is my industry standard very normal CPU core (no you cannot look at)

@gsuberland @ftg @whitequark exactly

@ftg @whitequark yeah that's why it's kind of funny, it is simultaneously a very common CPU and a very obscure CPU (ie it's hard to get comprehensive documentation, the devkit is literally an FPGA, etc)

Like they're not lying but they're trying to imply it's a normal CPU to use and be able to program which isn't really true

@whitequark Calling an ARC CPU industry standard is very funny to me