LPCXpresso IDEのトピックRe: Bit banding in RAM

Bit banding in RAM

lpcware — Wed, 15 Jun 2016 21:33:11 GMT

Content originally posted in LPCWare by Deepak Bansal on Fri Sep 28 05:27:11 MST 2012
Is entire RAM area of Cortex M3 is available for bit banding.

Re: Bit banding in RAM

lpcware — Wed, 15 Jun 2016 21:33:12 GMT

Content originally posted in LPCWare by daniel.widyanto on Thu Oct 04 01:05:44 MST 2012
Hi,

Nope. Only address 0x2000_0000 to 0x200F_FFFF and 0x4000_0000 to 0x400F_FFFF that's available for bit-band.

Most of NXP MCU has RAM at 0x10000000, which is not accessible for bit-banding feature.

Re: Bit banding in RAM

lpcware — Wed, 15 Jun 2016 21:33:13 GMT

Content originally posted in LPCWare by Deepak Bansal on Tue Oct 09 21:55:19 MST 2012
Hi, Thanks 4 ur reply.

Here is the link for cortex-m3 memory map:
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0182h/CHDBFJED.html

It states that SRAM address starts from 0x20000000.

But memory map of LPC1317 which is also cortex-M3 mcu shows that SRAM starts from 0x10000000 which according to above link falls into code segment.

Why is that?

Re: Bit banding in RAM

lpcware — Wed, 15 Jun 2016 21:33:13 GMT

Content originally posted in LPCWare by Deepak Bansal on Thu Oct 11 18:43:12 MST 2012
any help..........

Re: Bit banding in RAM

lpcware — Wed, 15 Jun 2016 21:33:14 GMT

Content originally posted in LPCWare by ArtjomGromak on Thu Oct 11 19:03:34 MST 2012

Quote: Deepak Bansal
Hi, Thanks 4 ur reply.
Here is the link for cortex-m3 memory map:
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0182h/CHDBFJED.html

Cortex-m3 has diffirent versions and versions has different memory map.

Quote: Deepak Bansal

It states that SRAM address starts from 0x20000000.

Look in LPC13 User manual.

Quote: Deepak Bansal

But memory map of LPC1317 which is also cortex-M3 mcu shows that SRAM starts from 0x10000000

Yes, SRAM in lpc13xx starts at address 0x10000000.

Re: Bit banding in RAM

lpcware — Wed, 15 Jun 2016 21:33:14 GMT

Content originally posted in LPCWare by Deepak Bansal on Fri Oct 12 03:16:15 MST 2012
Hi,

LPC1317 is cortex-M3, r2p1 processor.

& below is the link of arm site showing memory model for cortex-m3, r2p1:
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0337i/CACDCJFI.html.

SRAM starts from 0x20000000.
While in LPC1317 it starts from different address

Re: Bit banding in RAM

lpcware — Wed, 15 Jun 2016 21:33:15 GMT

Content originally posted in LPCWare by daniel.widyanto on Sun Oct 14 21:02:51 MST 2012
Read the LPC131x User Manual (UM10524) Chapter 2, Figure 2. The address 0x2000_0000 is occupied by SRAM

There are few SRAM banks in LPC131x, 0x1000_0000 is the standard bank, 0x2000_0000 is another extra SRAM bank. Both can be used for general purpose SRAM.