Microcontrollers become more difficult - acquire integrated hardware implementations of interfaces, the separation of flash memory for the bootloader and the main program.
Now the microcontroller itself(the loader) pierces through the serial interface, was used almost video recording internal memory while programming in parallel the interface - hence the pile of wires.
Sandra_Kautzer42 answered on June 26th 19 at 14:26
so it is possible and a conclusion to do.
reduction in signal lines complicates the internal logic of the programmer/debugger of. previously, the cost of the keys in the chip was a road, and therefore did not complicate the schemes is poor (the programmer used a couple of times during the entire life of the processor) nodes.
Now the cost of a penny, plus a tried and tested scheme, system, there are a bunch of waste of IP blocks and such. because put.