from the conventional "Serial Load Hardware Configuration":
to this one:*uses PL2303 from this cable: CHEAP USB-serial interface cable for our MCU projects!
*no other addtional IC (e.g 74xx125)
**but still need to place the external crystal on the DS89C4x0
inside the cdrking's nokia data cable:
connections (tapping of wires):
actual circuit:*has a pull-up on P3.7 pin (only for some batches of ds89c420 as indicated in their errata)
the 40-pin DIP DS89C420 (obsolete part):
the MTK (Loader software):*the actual hardware is not working with version 2.4.10
*works also with Loader420 and hyperterminal..
demo ("classic" LED blinker program):
SDCC code:Compiled using M-IDE with SDCC