13.2.7. Downloading new application versions

There are a number of techniques you can use to move successive versions of your application onto a development board. Each technique has advantages and disadvantages:

Using Angel with a serial port

This gives slow downloading, but has the advantage that it requires only a simple UART on the development board. If your board supports Flash download you can use this method to fix your image in Flash.

Using Angel with serial and parallel ports

This provides medium speed downloading, but requires a serial and a parallel port on the development board. If your board supports Flash download you can use this method to fix your image in Flash.

Using Angel with an Ethernet connection

This provides fast downloading, but requires Ethernet hardware on the development board and a considerable amount of Ethernet support software to run on the development board. If your board supports Flash download you can use this method to fix your image in Flash.

Flash download

This provides slow to fast downloading, depending on the type of connection you are using.

This method is only available on boards that have Flash memory and are supported by the Flash download program. It has the advantage that, after the Flash is set, the image is fixed in memory, even if the board is switched off.

You can also download application-only images using this method, but you cannot then use Angel.

Refer to your development board documentation for more information on downloading to Flash.

Using a ROM emulator to download a new ROM image

This provides medium to fast downloading, depending on the ROM Emulator. You must have access to a ROM Emulator that is compatible with the hardware.

You cannot replace application-only images using this method. You must replace the complete ROM image.

Blowing a new ROM or EPROM each time

This provides slow replacement in that it takes a relatively fixed amount of time to physically remove your ROM or EPROM, blow a new ROM image, and replace it. If you need to erase your EPROM this will add to the time required.

However, this method might be preferable for extremely large ROM images where only a slow download mechanism is available.

Replacing the ROM or EPROM also has the advantage that the application is permanently available, and does not have to be reloaded when the board is switched off.

You cannot replace only a part of the program using this method. You must replace the complete ROM image.

If you use one of the ROM replacement methods then you must change from building application images to building ROM images as soon as the development phase starts.

If you use a simple download method then the transition to the development phase is easier because you can move to building ROM images when everything else is working and you are preparing to move to production hardware.

Refer to The Flash downloader of the ARM Software Development Toolkit Reference Guide for information on using the Flash download utility.

Refer to The fromELF utility of the ARM Software Development Toolkit Reference Guide if you are using an EPROM programmer to program big-endian code into 16-bit devices.

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