RK002 code and data capacity?

capacitance

What are the memory specifications of the RK002?

How much code can I upload to it?

What is the maximum amount of dynamic memory that can be allocated?

albert

The amount of memory isn't that meaningful. For the intended use of the cable (=MIDI processing) there is plenty memory. If you want to create a DAW with it, it might be a little-bit under-spec :-)

amount of free code = +/- 14Kbyte
amount of free RAM = +/- 3Kbyte
(a propos: 'dynamic memory' = really?)

and by the way: it is possible to give up some code-space, and in stead use that as a non-volatile memory. This memory content is retained, even when the power is removed (!) (can be very usefull storing configuration data)

capacitance

Thanks.

So, it is not possible to receive and process, for example, a 10K sysex message (with only 3K of RAM available).

("Dynamic memory" is the standard term for variably-sized, heap-allocated memory in C/C++-like languages, no?)

Another related question...

When compiling code, is data declared in global/static in code allocated in RAM , or as part of the code image? For example, could I declare a global array, 10K in size, and use it to hold a large sysex message? (This assumes that the sysex message is "streamed in" in smaller chunks as it arrives, but it is not clear if that is how the RK002_onSystemExclusive callback works.)

So, last related question: What is the largest size sysex message that can be received via RK002_onSystemExclusive?

capacitance

That all said, I assume the cable will always pass any size sysex message, even if internal limitations might prevent it from being delivered to RK002_onSystemExclusive, no?

albert

max. size of sysex message = 256 bytes in the RK002 sysex parser. So no small chunks or whatever :-( (unfortunately; .. this maybe needs some improvement indeed; by default the cable will not pass-through messages bigger than that it seems)

however : you can implement
bool RK002_onRxByte(byte d) {}
yourself, and parse every byte received on the input 🫤

"Dynamic memory" : yes: variably-sized, heap-allocated, memory garbage generating, evil construct which should be avoided in realtime systems, because of it's intrinsic nondeterministic behaviour.

data declared as global/static is not per-se stored inside the code image, 'data' is 'initialized memory', and takes up ROM (for the init value) as well as RAM (for the working memory) (!)

if you want to store a sysex message you can declare it as 'const' (!) which will not take-up RAM memory, and only ROM/FLASH. In Arduino this is done by declaring a variable with 'PROGMEM' .. I'm not entirely sure whether the RK002 compiler also accepts this.

the API call 'RK002_sendSystemExclusive()' will happily send-out big chunks of sysex for you.

capacitance

Thanks for that info, that is useful.

I don't want to store a (pre-initialzied) sysex message as part of my program at compile-time. Rather, I am wondering about receiving and storing a sysex message that is larger than RAM (larger that 3K) at run-time.

As you pointed out (thanks), I could manually parse/recognize sysex messages longer than 256 bytes (say, several kilobytes long) by writing my own onRxByte() handler. But, maybe storing such a message is not possible?

I tried declaring a large (10K) uninitialized static buffer and compiling with (beta) online compiler:

byte bigData[10 * 1024];

It failed with this error:

linker: sketch section '.bss' will not fit in region 'RamLoc4' linker: region 'RamLoc4' overflowed by 6464 bytes collect2: error: ld returned 1 exit status

So, global/static data items are allocated in RAM, it seems? And so are limited to about 3K.