Port in tristate mode

jm · ‎2004-03-10

Posted on March 11, 2004 at 06:36

jm · ‎2004-03-09

Posted on March 09, 2004 at 11:44

Hi,

I work on ST10F168 with 6M*16bits external ram.

This external Ram is used by the microcontroller and a xilinx, so the datas and adress bus are divided by 2 chips.

I would to know if i can put POL & POH & P1L & P1H & P4 in tristate mode when the xilinx is accessing external Ram. Can i do this manually by software or using HOLD,HLDA,BREQ signals with logic combination?

I see this signals work automatically but i don't know if it work with another chip. If it can, how does it work?

Thanks

Regards,

Jim

charles239955_st · ‎2004-03-10

Posted on March 11, 2004 at 06:36

Hello,

The bus arbitration mechanism can work with any other chip.

See the attached pdf pages extract from the ST10F269 user manual.

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Attachments :

Bus_arbitration.pdf : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I0OP&d=%2Fa%2F0X0000000bYR%2FBMoyXuq2HoGirzkKUMYXrKVqwBlUmDOq2tO0ArYUvkc&asPdf=false