Use of AHB SRAM

[jean-marcrouxel]

I'm working on a LPC4337.

I want to use the AHB SRAM (32 KB at 0x2000 0000, 16 KB at 0x2000 8000 and 16 KB at 0x2000 C000) to store program.

Question 1 : what are the differences between local SRAM and AHB SRAM? The AHB SRAM access time is the same as for local SRAM?

Question 2 : I want to use it to store program (no data). These areas are contiguous, aren't they ? So I just have to define one area in my scatter file (from 0x2000 0000 to 0x2000 C000) and not 3 differents ?

Jean-Marc

[soledad]

Hello Jean-Marc,

Please check the below image, you can find the system memory map, the AHB SRAM areas are contiguous.

"When the ETB is used, the 16 kB memory space at 0x2000 C000 must not be used by any other process."

When Bit0 = 0 ETB accesses SRAM at address 0x2000 C000.
When Bit0 = 1 AHB accesses SRAM at address 0x2000 C000

Please check the value in the ETB SRAM configuration register (ETBCFG, address 0x4004 3128).

In addition please check the below thread Can't Access AHB SRAM on LPC4350 at adress 0x20004000 

Have a great day,
Sol

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