Post by thread:[PIC]: No MAX232 needed with PIC16F628 ?

Hi, am I right to assume the PIC16F628 does not need a MAX232 chip, since it is a hardware usart (RB1(RX)/RB2(TX) ? I checked the data sheet and searched the archives, but no luck. Thanks in advance, Kevin -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Depends: the MAX232 converts the UART I/O to RS-232 levels (inverted +-12V). If you are communicating with an RS-232 device you probably need it. You could equally communicate via RS-485, RS-422, MIDI, or whatever uses a serial protocol using the same USART but you will need different hardware to transform the signals to/from TTL levels. /\/\/\/*=Martin {Original Message removed}

Thanks Martin and Wouter, you both answered my question :) I guess I should have been clearer in asking it. I wanted to communicate with my PC serial port, and I was a little confused on what the usart actually did. I have used bit banged RS232 with the F84 with a MAX232 and without. So, I probably will use one with the F628, to get true RS232 levels. Thanks again, Kevin {Quote hidden}> >> Hi, >> am I right to assume the PIC16F628 does not need a MAX232 chip, since >> it is a hardware usart (RB1(RX)/RB2(TX) ? I checked the data sheet and >searched >> the archives, but no luck. >> >> Thanks in advance, >> Kevin >> >> -- >> http://www.piclist.com hint: PICList Posts must start with ONE topic: >> [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads >> >> > >-- >http://www.piclist.com hint: PICList Posts must start with ONE topic: >[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Actually with the hardware UART you kinda have to use a level converter since the polarity of RS232 is the inverse of the TTL that comes out of thge UART (a '1' in RS232 is a negative voltage while in standard TTL a '1' is a positive voltage). TTYL > {Original Message removed}

>So, I probably will use one with the F628, to get true RS232 levels. I like the F628, but you still need the MAX232 interface chip in order to get RS232 voltages. Jay -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads