[SOLVED] Unknown Port in Raspberry pi 4
Can anyone tell me what is this port back of the Raspberry Pi 4 B
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Last edited by ASCII8BiT on Fri Jan 03, 2020 1:18 pm, edited 1 time in total.
Re: Unknown Port
JTAG interface for the VideoCore VPU. It isn't populated because it is useless for everybody except Raspberry Pi engineers working on the firmware. The JTAG interface for the ARM cores is on the GPIO header as one of the alternate functions.
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klricks
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Re: Unknown Port
JTAG port used during manufacture to set the serial number etc.
Unless specified otherwise my response is based on the latest and fully updated RPiOS Buster w/ Desktop OS.
Re: Unknown Port
It's not actually used in manufacture. Production test uses a custom buildroot image on SD card to flash the various EEPROMs and run the suite of test routines. The port is strictly for Videocore firmware development and debug.
Rockets are loud.
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