Issue with EBI on A1U Xplained PRO board

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Hi guys,

 

I'm playing around with the XMEGA A1U Xplained PRO board and I manage to get the SRAM running with the EBI ASF libraries. I have an issue though, I can't access to the whole ram, I can only access to the first 256kB, for some reason the A18 (PK7) line is not being activated, do you have any experience with this?

 

config code:


ebi_setup_port(19, 0, 3, EBI_PORT_3PORT | EBI_PORT_SRAM | EBI_PORT_CS2);

ebi_cs_set_mode(&cs_config, EBI_CS_MODE_LPC_gc);
ebi_cs_set_address_size(&cs_config, EBI_CS_ASPACE_512KB_gc);
ebi_cs_set_base_address(&cs_config, BOARD_EBI_SRAM_BASE);

ebi_cs_set_sram_wait_states(&cs_config, EBI_CS_SRWS_1CLK_gc);

ebi_cs_write_config(2, &cs_config);

ebi_enable_cs(2, &cs_config);

 

conf_board.h:

 

#define CONFIG_HAVE_HUGEMEM

#define BOARD_EBI_SRAM_BASE    0x40000UL

#define BOARD_EBI_SRAM_SIZE    0x40000UL

 

Thanks!

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Hi! For the 3rd parameter of the ebi_setup_port() the ASF documentation says:

lpc_ale - Number of address latches to enable for LPC mode, 0 to 2 - but you have there 3

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From the schematic:

 

Greg Muth

Portland, OR, US

Xplained/Pro/Mini Boards mostly

 

Make Xmega Great Again!

 

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Attached is a solution/project that initializes the EBI w/o using ASF calls.

 

 

Attachment(s): 

Greg Muth

Portland, OR, US

Xplained/Pro/Mini Boards mostly

 

Make Xmega Great Again!

 

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I see now. The A18 pin of the SRAM is not connected to the EBI A18 signal output but somewhere else. This means that you have to set it manually before every read/write if you want to use it.

 

For EBI, the A18 and the CS2 signals share the same pin so when CS2 is enabled, the A18 is not available. This was the reason why they connected it to another pin.

See XMEGA AU Manual > EBI > I/O Pin... > SRAM 2/3/4 PORT ALE12 column in the table.

 

But what if one would move the CS signals to another port (EBICSOUT bits)? Would then all the address signals be available? (XMEGA AU Manual > I/O Ports > Reg. Descr. - Port Configuration > EBIOUT > EBICSOUT)