Booting ADSP TS 201S TIGER SHARC FROM EXTERNAL FLASH

Hi Mohit,

I'm going to assume that all three processors are going to interface to a single flash memory. If you plan on booting from this flash memory then you will need to interface the /BMS signal for the device for the chip select.

The Boot memory select memory space is limited ro 16MB so this is the amount of memory space that is shared between all three processors.

Q) The size of the code that would be required to boot each of the three with different code and data respectively

This question is a little bit difficult for anyone to answer. The processors will first of all boot in a maximum of a 512 byte boot kenrel, but after this you can boot the proceccors with as little as acouple of bytes if the processor is to simply site there and enter "idle" or you can boot it with a full blown application. This a question in which only you can are able to answer depending on the application that you wish to load.

Q) The interfacing requirements

I would suggest you take a look at the ADSP-TS201 EZ-KIT schematics for details of the iterfacing requirements. These schematics also interface the /MS0 signal to the flash chip select line. Not only does this allow for the /BMS signal to be used for booting purposes but it also maps the flash device to the MS0 memory space which can support greater than 16MB of addressible memory.

Q) Whether Visual DSP supports only specific flash memories for programming the boot flash memory

The VisualDSP++ software does only ship with the flash programmer drivers for the flash devices populated on the EZ-KITs. The full source code however is included in the VisualDSP++ installation directory and can be easily adapted to suite other flash devices, especially if it's a flash device that supports the same commands etc for the basic programme operations. I would suggest to take alook at the software drivers fro the flash programmers included with the tool chain, it's fairly straightforward to follow and check that the command sequence required for a program operations is the same for your choses device. The flash device on the EZ-KIT performs a flash unlock operation:

See the function UnlockFlash() in file "adi_at49bv040.c". This details the flash unlock operation required before a program operation. Hopefully, based on your flash device you should only need to make some slight modifications to this function in order to get the flash programmer working with your device.

Q) I want to use the asynchronous read mode for reading the flash.Is there anything else I need to take care of?

You will obviously need to hook the lfahs up to the memory slelect space such as MS0 like in the EZ-KIT if you wish to use the basic asynchronous read and write operations. This would need to be in addition to interfacing the flash to the /BMS signal if the flash is also to be used as a boot source. One thing you should be aware of is the fact that the flash boot source is 8-bits. If you hook up an 8-bit flash also to the /MSx memory space then you will need to perform padding of the data as you can only write to the /MSx interface in 32- or 64-bit transactions, so you need to pad the data accordingly before a write operation or discard the redundant data then shift it for read operations. If you do a DMA in "prom" mode then the 8-bit read operations are all packed automatically but will still need to pad the data for program operations.

Regards

Andy

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