Add support for modifying USB strings during runtime #3

jedrzejboczar commented 2019年11月29日 17:27:53 +01:00 (Migrated from github.com)

This is to allow FX2 to set some USB strings that are being read from other devices.

This is to allow FX2 to set some USB strings that are being read from other devices.

jedrzejboczar commented 2019年11月29日 18:50:59 +01:00 (Migrated from github.com)

Travis fails while linking boot-dfu because there is not enough RAM space, but I cannot reproduce this when building with exactly the same flags. Could it be related to SDCC version?

Travis fails while linking boot-dfu because there is not enough RAM space, but I cannot reproduce this when building with exactly the same flags. Could it be related to SDCC version?

whitequark commented 2019年11月29日 18:53:09 +01:00

You don't need any new code for this, just cast away the __code const qualifiers like here and replace them with __xdata. (Of course, this is only legal to do on the FX2, since 8051 code and xdata spaces don't have to address the same memory in general.)

That's a bit dirty, and perhaps it would be better to have all descriptors mutable and __xdata in the first place. But I think it should be one of those two options rather than adding any new code.

You don't need any new code for this, just cast away the `__code const` qualifiers like [here](https://github.com/GlasgowEmbedded/glasgow/blob/master/firmware/main.c#L252-L265) and replace them with `__xdata`. (Of course, this is only legal to do on the FX2, since 8051 code and xdata spaces don't have to address the same memory in general.) That's a bit dirty, and perhaps it would be better to have all descriptors mutable and `__xdata` in the first place. But I think it should be one of those two options rather than adding any new code.

jedrzejboczar commented 2019年12月02日 09:26:10 +01:00 (Migrated from github.com)

Thanks. This is of course much better solution. In fact I tried to do this, but missed the __xdata specifier. Should have known that with small memory model it is needed.

Thanks. This is of course much better solution. In fact I tried to do this, but missed the `__xdata` specifier. Should have known that with small memory model it is needed.