[URGENT] Is 32 bit NOR flash booting available on At91sam9m10 based device ?

Discussion around AT91RM9200 and SAM9 Series Products.

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nexfield
Posts: 3
Joined: Fri Oct 31, 2014 12:08 pm

[URGENT] Is 32 bit NOR flash booting available on At91sam9m10 based device ?

Tue Jan 16, 2018 2:16 pm

Hello every one.

We have big problems on NOR flash booting.
We've designed our custom device with 32bit NOR flash , actually 2×16 NOR configuration on NCS0.
Say 1 NOR device is connected with D0-D15 data bus, and the other one is connected with D16-D31 EBI1 data bus.


We tried to read NOR device ID by using modified Samba applet, but we couldn't access the upper flash device connected to D16-D31 ( EBI1 data bus ).
Say more detail, the value was always 0xffff, and the data bus were not changed in spite of writing on it.

Thus, we doubt that the at91 processor doesn't support 32 bit data bus for NCS0.

Could anyone tell us clearly?

Please send a mail for me.

Thanks very much in advance.

D.M. Kim
Email : dmkim@nexfield.net
blue_z
Location: USA
Posts: 1704
Joined: Thu Apr 19, 2007 10:15 pm

Re: Is 32 bit NOR flash booting available on At91sam9m10 based device ?

Wed Jan 17, 2018 3:22 am

nexfield wrote:Say 1 NOR device is connected with D0-D15 data bus, and the other one is connected with D16-D31 EBI1 data bus.
Starting a sentence with "say" indicates a hypothetical situation.
Is your board real or hypothetical?

nexfield wrote:We tried to read NOR device ID by using modified Samba applet, but we couldn't access the upper flash device connected to D16-D31 ( EBI1 data bus ).
Say more detail, the value was always 0xffff, and the data bus were not changed in spite of writing on it.

Thus, we doubt that the at91 processor doesn't support 32 bit data bus for NCS0.
Samba is a network protocol.
Don't you mean SAM-BA?
If that's the extent of testing your hardware, then IMO that's a rash conclusion (which is backwards).

Your testing doesn't match your title.
The datasheet clearly answers your title:
On startup the "Static Memory Controller (SMC) in default configuration (byte select mode, 16-bit data bus, Read/Write
controlled by Chip Select, allows boot on 16-bit non-volatile memory
".


nexfield wrote:Please send a mail for me.
Don't ask people to reply by private e-mail.

Regards
nexfield
Posts: 3
Joined: Fri Oct 31, 2014 12:08 pm

Re: [URGENT] Is 32 bit NOR flash booting available on At91sam9m10 based device ?

Thu Jan 18, 2018 12:40 pm

Hello blue_z
Thanks for your kind reply.

Do you mean At91 processor doesn't support 32-bit NOR (actyally 2×16 NOR) flash?
If booting from 16-bit NOR device is possible,
ARM mode instructions(4-byte word instruction) could be executed from 16-bit NOR?

We are using Windows CE as embeddes OS on our custom device, and I believe WINCE can only support with ARM mode.

If AT91 processor could support booting from only 16-bit NOR device , not 32-bit NOR device , Windows CE could not be booted from such configuration (from external 16-bit NOR device).

I think booting from 16-bit NOR may require 16-bit instruction, likely THUMB mode.
Am I wrong?

I hope to get your reply.

Thank you.

D. M. KIM
blue_z
Location: USA
Posts: 1704
Joined: Thu Apr 19, 2007 10:15 pm

Re: Is 32 bit NOR flash booting available on At91sam9m10 based device ?

Fri Jan 19, 2018 2:53 am

nexfield wrote:Do you mean At91 processor doesn't support 32-bit NOR (actyally 2×16 NOR) flash?
No, I wrote nothing close to that.
Do not conflate booting from a NVM with accessing a NVM.
The default SoC configuration on startup mandates a 16-bit interface for the SMC NVM when used for boot.
If the SMC NVM is not the boot device, then the interface could be 8, 16, or 32 bits.

nexfield wrote:If booting from 16-bit NOR device is possible,
ARM mode instructions(4-byte word instruction) could be executed from 16-bit NOR?
There's nothing in the datasheet that states otherwise.

nexfield wrote:I think booting from 16-bit NOR may require 16-bit instruction, likely THUMB mode.
Am I wrong?
Yes, according to the datasheet you are wrong.
From the datasheet: "All instructions fetches, regardless of the state of ARM9EJ-S core, are made as 32-bit accesses on the AHB.
If the ARM9EJ-S is in Thumb state, then two instructions can be fetched at a time.
"

Regards
nexfield
Posts: 3
Joined: Fri Oct 31, 2014 12:08 pm

Re: [URGENT] Is 32 bit NOR flash booting available on At91sam9m10 based device ?

Fri Jan 19, 2018 7:57 am

Thanks blue_z

I will consider of using seperate boot ROM with our 2x16bit NOR flash of our custom product.

Since Windows CE bootloader nomally requires 256KB code size , I think serial EEPROM would be proper on our purpose.

However I'm wondering it would be robust enough solution.
You know the robust booting is very important to industrial product like our coustom product.

Or could you recomend any other booting solution in case of our product having 2x16 bit external NOR devices?

Thanks and be good weekend.

D.M. Kim

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