where is the Localbus for mpc8247, I can find PCI and 60X bus in the datasheet.

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where is the Localbus for mpc8247, I can find PCI and 60X bus in the datasheet.

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ivanfeng
Contributor I

where is the Localbus for mpc8247, I can find PCI and 60X bus in the datasheet.

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alexander_yakov
NXP Employee
NXP Employee

MPC8247 device does not have local bus, it has only PCI.

For other MPC82xx family devices, for example MPC8280, there is a possibility to select between Local bus and PCI, but in MPC8272 family devices (MPC8272, MPC8271, MPC8248, MPC8247) there is no Local Bus block.

(Because of this reason, PCI must be always enabled. If PCI is not used, it should be properly terminated, leaving PCI floating is not correct.)

Note that the local bus in MPC82xx devices is not "common" local bus, present in MPC83xx and later devices. In the MPC82xx devices local bus is special bus designed to be directly accessible by CPM (CPM has direct data path to local bus), so CPM could access local bus directly, without blocking 60x bus. This theoreticaly could give a performance benefit for CPM-initiated accesses, for example for SDMA transfers from communication controllers FIFO to buffers in memory.

If you mean local bus in "common" sence, i.e. as a bus to connect boot flash and SDRAM memory, than you have to use 60x bus, but not local bus.

Please look schematic of our "MPC8272ADS" board and use as reference:

MPC8272ADS: Application Development System for MPC8272

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ivanfeng
Contributor I

hi alexander.yakovlev

thank you for replying.

It must be a mistake on freescale`s home web.

but it doesn`t matter, Ti am3359 is the right one for me now.

mpc8247 is 10 years ago`s product, I need to persuade myself to abandn it.

thank you again.

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