Questions in PCIe BAR

Question

1. Why do we need BAR in PCIe?

2. Why do we need multiple BARs in PCIe?

3. How do we choose type of BAR in PCIe? (64 bits/34 bits, Prefetchable/non-prefetchable)

4. With multiple devices (a RAM, a FIFO, a DMA and few I/O Registers) connected to PCIe, how do we know which BAR to connect to which device?

Thank you,

Ranmu

altera_forum · Answer

BAR stands for Base Address Memory and you use them as a reference address when you want to access for example a PIO component from your software.

You decide which BAR will be connected to which device. Dont forget that you will use these addresses when you will write your driver.

altera_forum · Answer

Dear Tonisss,  Thank you for the reply.  It helps me to understand more about PCIe.  Thank you again, Ranmu

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