... using the serial DSUB9 connector - as it is connected now, you can't use a standard cable.
Also, make sure you understand which gender you'll use.
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What I am doing quite often now is, I take a piece of protoboard (for soldering, but not the isolated pins type but the short strips type, that works the best for me), and wire up the following:
,
- a power source:
- socket for the wallwart plug
- series diode (a bridge is more comfortable but not necessary)
- a fat cap (470uF/16V or so)
- a slim cap (100nF) close to the 7805's terminals
- 7805
- another slim cap (100nF) close to the 7805's terminals
- and the resulting 5V and GND goes to the long "rail" lines
- a DIL40 socket for the '51
- (I almost always use the "precision" sockets, yields better sleep :-) )
- GND and VCC connect to the "rails"
- and an another slim cap (100nF) as close to the power terminals as possible(e.g. under the socket)
- reset
- for *beginning*, a cap (say 10uF/16V or so) from pin 9 to VCC will do, but consider something decent later, please
- a manual reset pushbutton from pin 9 to VCC
- crystal
- as close as possible to pins 18 and 19
- 27pF (22-33pF will do) caps with as short connections as possible - I often use SMD caps there
- /EA to VCC (!important)
- /PSEN via cca 1k resistor to a pushbutton to GND (for the ISP entry)
- MAX232 (but better a version dedicatedly using 100nF caps), you will need 5 (five) caps (I use 100nF so I don't need to be bothered with the polarity) - 1-3, 4-5, 2-VCC (but 2-GND will do on the protoboard), 6-GND, and don't forget, 15-16 (power decoupling). All caps as close to pins as possible.
- P3.0 and P3.1 through MAX232 as appropriate, and then Rx goes to pin 3 and Tx to pin 2 of DSUB9F (pin 5 to GND). This allows to use the "straight" COM cable. I use a cable type DSUB9F pushed on the edge of the PCB, the pin spacing does not match but for the 5 pins you'll need it will do.
- a LED from a port pin (say, P3.3, or any other) via 1k resistor to VCC (for the "blinkey" test).
The DIL40 allows you to use AT89C51RD2, P89V51RD or DS89C450, all of them have their ups and downs. All of them have a dedicated "programming" software - FLIP, FlashMagic, and I don't remember the Dallas one :-)
After you manage blinkey (which is still a long journey to go - learning hows and whys of asm and/or C, peculiarities of the innards of '51, trying a simulator, learning how to download etc.), you can add LCD, pushbuttons (and maybe even the ADC if you insist on it) etc. easily.
Not worth making your own PCB until you managed this. This all costs a few pennies and will teach you a lot. If you are afraid of the soldering gun, buy a readymade protoboard, such as the 8052.com SBC.
IMHO not really worth starting with the Silabs's, but YMMV.
JW
