[microblaze-uclinux] What is the maxium BRAM?

["Qichen Huang" <huangqichen@xxxxxxxx>]

Hi all,
I'm now quite confused by the BRAM configuration. On the spartan 3E datasheet, XC3S500E should have 360Kbit Block RAM. But when configuring the MicroBlaze with 8KByte On-Chip RAM for data and instruction (ilmb and dlmb), the RAM usage is already 100%, 20 of 20 Blocks. Where are the other BRAMs?

And for Virtex 4. When configuring XC4VFX12 with PowerPC, I can use 4KByte docm_cntlr and iocm_cntlr and 64KByte plb_bram_if_cntlr. But with MicroBlaze, 32KB opb_bram_if_cntlr is already overmapped. (4KByte ilmb and dlmb).

Why is there a difference between MicroBlaze and PowerPC? Does the MicroBlaze use some of the RAM resource for itself?

Qichen