Rikard, I am sorry for the ambiguity. By write-not I mean the write signal (WR) is active low. It is the write signal with the bar over the it. And by read-low I mean that the read signal is active low. It is the read signal (RD) with the bar on top. ----- Original Message ----- From: "Vasile Surducan" To: "Microcontroller discussion list - Public." Sent: Wednesday, May 30, 2007 1:17 AM Subject: Re: [EE] Bidirectional bus driver direction control > Depends. If you take a look here: > http://www.geocities.com/vsurducan/electro/8255/8255.htm > you'll see it's read-not. As I remember read-not and write-not signals are > in opposite phase but that depends hardly on your system timings. > > greetings, > Vasile > > On 5/29/07, Rikard Bosnjakovic wrote: >> On 5/30/07, Rich wrote: >> > Hi all. If I use a 74LS245 bidirectional bus transceiver is the >> > write-not >> signal the one to the direction control pin? Or can either the write-not >> or >> read-not be used to control the direction? >> >> I'm not sure what you mean by "write-not" and "read-not". >> >> The 74LS245 has got two pins that control the flow, the DIR (pin 1) >> and G' (pin 19). The DIR selects if the bus A should move to B, or B >> to A. The G' effectively turns the whole bus ON or OFF. >> >> >> -- >> - Rikard - http://bos.hack.org/cv/ >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist