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furrtek / SiliconRE

Traces, schematics, and general infos about custom chips reverse-engineered from silicon
GNU General Public License v2.0
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315-5195 wrong pins ~BR/~BGACK #15

Open jotego opened 2 years ago

jotego commented 2 years ago

pin_br_out appears as a fixed low, which would stop the M68000 forever as that is the bus request signal.

The /pin_br_en doesn't go anywhere either.

A similar story applies to BGACK.

furrtek commented 2 years ago

Confirming that the output level for both pins BR and BGACK is fixed low.

/PIN_BR_EN and /PIN_BGAC_EN go straight to the IO blocks, they're used to enable the open-collector output of those pins.

After reset both signals should be set high, effectively leaving the pins in hi-z (there might be an internal pull-up in the chip ?).