View Full Version : Whats the use of a MAX233 chip?

01-09-2006, 05:39 AM
I've seen people using this chip around the forums, to connect the BS2 to the serial (or usb) ports on their PC's. Is it necessary to have this chip to convert RS232 voltage levels to TTL ? I mean, I connect my serial-to-usb cable directly between my PC and the BS2 for programming the microcontroller, and there doesnt seem to be any problem.. So in which case would i have to use that MAX233 chip ?


01-09-2006, 06:21 AM
The MAX232/233 chip is helpful if you want to use flow control and higher baud rates. Note some RS232 devices require flow control to operate properly.

Steve Joblin
01-09-2006, 06:48 AM
I am using it as the core of my "Basic Stamp Lite" programmer...·I have simplified the Basic Stamp to just have the pre-programmed PIC, EEPROM, and resonator... all of the other components are for supporting communications (which I am building based on the MAX232).

01-09-2006, 07:07 AM
The BS2 has a built-in circuit so you can program it with 'true' RS-232 levels. Sometimes its nice to have a second port. The MAXIM Max232 chip gives you that -- but you have to wire in 4 capacitors. The Max233 doesn't require external capacitors.

Steve Joblin
01-10-2006, 07:54 AM
Great! Now I find out I could simplifiy by using a 233 and not needing the 4 extra caps.... Oh well, guess I will be including a 233 in my next purchase!

01-12-2006, 03:14 AM
The draw back to a max233 is that they are more expensive.· Digikey has DIP max233's for·$10 and $14 each.· That's not bad if you are doing a one of a kind project but if you are doing quantity it adds up quickly.· You can get a comparable line driver IC for much less even when you add in the price of the required caps.

www.speechchips.com (http://www.speechchips.com)

Speech & Video IC's for BasicStamps

01-12-2006, 11:53 AM
thanks a lot, this helped me a lot