-Does the Arduino Serial Board (pic 1) works and programs exactly like an Arduino Uno/Duemilanove? (A Serial - USB cable needed, pic 2)
-Can the ATMega 8 be replaced with the ATMega 328?
-Does it run the uploaded sketch through the USB - Serial Cable?
-Is there only 3 Serial Connections (pic 3, bottom left) to the Serial socket?
-Is that (pic 3, top left) the power jack?
-How does it power itself? through Serial-USB?
im not really sure if this is the correct explanation but the ftdi chip used to provide usb to serial on the newer boards has a DTR pin which according to the datasheet is
Output Data Terminal Ready Control Output / Handshake Signal.
which could mean that when the chip is preparing to send data the pin changes state and makes the atmega reset
now the rs232 connector has a pin that its called DTR but im not sure if it does the same thing as the ftdi chip and if it does why isn't it used to provide an auto reset function - but if it does the same thing you could solder that pin with a capacitor to the reset pin and "enable" auto-reset
anyway i could be wrong maybe someone knows what really happens there
But I found another version (Single sided) on http://arduino.cc/en/Main/ArduinoBoardSerialSingleSided3 that it has a auto reset by just adding a 100nF capacitor and connect it to pin 4 on the DB9 serial socket (refer schematic below). So is it possible to auto-reset now?
J P 4
2 p i n s ju m p e r
W h e n i n p o s i t i o n 1-2, t h i s j u m p e r e n a b l e s a u t o r e s e t f e a t u r e, u s e f u l
w h e n u p l o a d i n g a s k e t c h t o A r d u i n o , r e s e t t i n g A t m e g a a u t o m a t i c a l l y .
I t m a k e s u n n e c e s s a r y t o p r e s s r e s e t b u t t o n ( S 1 ) w h e n u p l o a d i n g
s k e t c h e s .
B e s u r e t h a t c o m p u t e r C O M P o r t s p e e d i s s e t t o 1 9 2 0 0b p s o t h e r w i s e
a u t o r e s e t w i l l n o t w o r k p r o p e r l y .
I f r e m o v e d , d i s a b l e s a u t o r e s e t f e a t u r e . V e r y u s e f u l t o p r e v e n t
u n d e s i r e d A t m e g a r e s e t w h e n u s i n g s k e t c h e s tha t n e e d s s e r i a l
c o m m u n i c a t i o n .
A u t o r e s e t w o r k s w i t h D T R p u l s e o n s e r i a l p i n 4 . S o m e t i m e s A r d u i n o
s e n s e s a D T R pu l s e w h e n c o n n e c t i n g X 1 ( s e r i a l c o n n e c t o r ) a n d s o m e
s o f t w a r e s s e n d s a D T R p u l s e w h e n i t s t a r t s o r w h e n i t c l o s e s , t h a t
m a k e s A t m e g a r e s e t w h e n n o t d e s i r e d .
If you do indeed want or require a RS-232 connected arduino board, there is a far better and more modern circuit to model around, see below. I bought this kit as my first arduino board and it still is functioning well for me. Kit price is now down to $17. It uses a proper max232 type RS-232 to TTL interface chip and implements the auto-reset function.
A max232 circuit is a real ttl to rs232 voltage level converter, and it will give you "real" rs232 on the port, and insulate you from certain types of badness that might occur on real rs232 ports that are connected to the input.
The transistor circuit in the original steals power for the arduino sending from the receive line, which is clever, but a bit prone to failure. Also, it'll only provide +5V for the "mark" level on the line (which is technically OK, but the +9V that the max232 will give you is better.)
OTOH, component costs for the max232 circuit probably start at about $1 and probably can't be bought at the local store, while the transistor circuit is $0.25 and works with "junkbox" components.
maybe someone knows what really happens there
