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Question on HPI bootup and switch to EMIF mode

Started by zhon...@senao.com June 22, 2007
I have a question about EMIF/HPI mode in C5507. It is true that we can not use HPI and EMIF at the same time, but the question is

Can we use HPI mode to boot up DSP when power up and then switch to EMIF
mode by the application code after that?

Thanks
Zhongkai-

> I have a question about EMIF/HPI mode in C5507. It is true that we can not
> use HPI and EMIF at the same time, but the question is
>
> Can we use HPI mode to boot up DSP when power up and then switch to EMIF
> mode by the application code after that?

It might work, but TI won't officially support this. I got something like this to work once for C5421, booting it
first into multiplexed-HPI mode, then switching it over to non-multiplexed. I think also we had to apply some
software strangeness, like throwing out the first few HPI transfers.

In the worst-case, your DSP code can use external circuitry to change the boot-mode Rs, then re-apply Reset and come
up in EMIF mode. That would be safe and officially supported, and your DSP code would be loaded, which I assume is
the objective.

-Jeff
Hi,

I have worked with C5502, I am not sure the things are same with 5507 or
not. In our case we manage like this.

1. Host downloads First BootLoader into internal DARAM of C5502 and does
kick start for execution after downloading first Bootloader. First
Bootloader is located in internal DARAM only.

2. When this first bootloader executes, it Checks integrity of External
SRAM. First bootloader wait for any memory block to write in external RAM.
Host will ask First bootloader to write block of memory into external SRAM
with specific Address. First bootloader writes that memory.

3. After downloading complete application onto external SRAM through First
Bootloader, Host ask First BootLoader to jump to entry point of External
Application which is loaded into External Ram. This way control goes to
external loaded application in SRAM.

In our case Host is capable of parsing coff (object) file and can determine
address to load.

- Prakash

_____

From: c... [mailto:c...] On Behalf Of
z...@senao.com
Sent: Thursday, June 21, 2007 11:35 PM
To: c...
Subject: [JUNK 1] [c55x] Question on HPI bootup and switch to EMIF mode

I have a question about EMIF/HPI mode in C5507. It is true that we can not
use HPI and EMIF at the same time, but the question is

Can we use HPI mode to boot up DSP when power up and then switch to EMIF
mode by the application code after that?

Thanks
Prakash-

> I have worked with C5502, I am not sure the things are same with 5507 or
> not. In our case we manage like this.

C5502 allows HPI and EMIF operational at the same time. C5507 does not.

-Jeff

> 1. Host downloads First BootLoader into internal DARAM of C5502 and does
> kick start for execution after downloading first Bootloader. First
> Bootloader is located in internal DARAM only.
>
> 2. When this first bootloader executes, it Checks integrity of External
> SRAM. First bootloader wait for any memory block to write in external RAM.
> Host will ask First bootloader to write block of memory into external SRAM
> with specific Address. First bootloader writes that memory.
>
> 3. After downloading complete application onto external SRAM through First
> Bootloader, Host ask First BootLoader to jump to entry point of External
> Application which is loaded into External Ram. This way control goes to
> external loaded application in SRAM.
>
> In our case Host is capable of parsing coff (object) file and can determine
> address to load.
>
> - Prakash
>
> _____
>
> From: c... [mailto:c...] On Behalf Of
> z...@senao.com
> Sent: Thursday, June 21, 2007 11:35 PM
> To: c...
> Subject: [JUNK 1] [c55x] Question on HPI bootup and switch to EMIF mode
>
> I have a question about EMIF/HPI mode in C5507. It is true that we can not
> use HPI and EMIF at the same time, but the question is
>
> Can we use HPI mode to boot up DSP when power up and then switch to EMIF
> mode by the application code after that?
>
> Thanks
Jeff:

Thanks very much. But I still have something unclear. I want to download the DSP codes from a host MCU via the HPI bus each time power up. After the DSP codes has been transfered to DSP, I want to switch to EMIF mode because I need use this data bus. If I use an external circuit to reset and switch to EMIF, I wonder if my DSP codes in memory will be lost because of the reset.

Thanks
Zhongkai
Zhong Kai-

> Thanks very much. But I still have something unclear. I want to download
> the DSP codes from a host MCU via the HPI bus each time power up. After
> the DSP codes has been transfered to DSP, I want to switch to EMIF mode
> because I need use this data bus. If I use an external circuit to reset
> and switch to EMIF, I wonder if my DSP codes in memory will be lost
> because of the reset.

Memory contents will only change if you remove power from the DSP. You should be
careful with Reset vector, and what code the DSP will execute immediately after
Reset.

-Jeff