Just a quick clarification of Mr Knapp's amplification on my posting... ;-)

the evaluation version of Keil creates code that only runs when programmed into external Flash

The restriction is that the Eval Linker will only produce code located from address 0x4000; that's a standard Keil restriction on all their C51 Evaluations - not something specific to Triscend.

On the board in question, this restricts you to running from FLASH - because that's what the board has.
However, if your target happened to have RAM at that address, you would be able to download & run code in it - Keil does not restrict you specifically to FLASH, and the Triscend tools support download & run in RAM.

Similarly, if you used one of the bigger Triscend devices (eg, TE520) which does have internal RAM above 0x4000 then you could use that with the Keil Eval tools.