As a newbie i want to ask about the easiest or better way to establish communication between mainboard PC with Microcontroller?using PPI8255 or Serial?
But if i want to use 2 microcontrollers ( DT-AVR 8535 ) and RS232 port from PC, what device should added between them ( mainboard PC can communicate with 2 mircocontrollers separately ) ?
And what are the different between RS232 and RS485? advantage and disadvantege between them?
But if i want to use 2 microcontrollers ( DT-AVR 8535 ) and RS232 port from PC, what device should added between them ( mainboard PC can communicate with 2 mircocontrollers separately ) ?
And what are the different between RS232 and RS485? advantage and disadvantege between them?
If u use MAX232 or compatible, it has two RS232 tranceivers on single chip. So, two microcontrollers can communicate with pc, both at a time if you use two different ports on pc.
RS232 signals are +15, -15 referenced to ground, while RS485 signals are differential. Also, RS485 is multipoint communication where many devices can be connected on a single RS485 bus. the problem is, PCs don't have RS485 port,so u need a RS485/RS232 converter!!
my adviser told me to find out about serial and PPI8255, i don't really know if PPI 8255 is antique.....
@All
So can i say to make my PC board ( with only 1 serial port ) can communicate with 2 µcontrollers separately ( multipoint communication ), it's better to use RS485/RS232 converter ( PC board -> RS485/RS232 -> 2 µcontrollers ) ?
Max3162 can do the job. it's an RS232-RS485 protocol translator. the RS232 side u can use for connecting with PC and both your controllers can be connected on RS485 line.
refer to this application note from maxim: **broken link removed**
And here is a simple RS232/485 converter using the max232 & max485: **broken link removed**
for starting on RS485, u can refer to this application note on RS422/485 bus:
**broken link removed**