From mboxrd@z Thu Jan 1 00:00:00 1970 To: "yhxing" Cc: "linuxppc-embedded@lists.linuxppc.org" Subject: Re: How to control RTS signal ? From: Wolfgang Denk Mime-version: 1.0 Content-type: text/plain; charset=ISO-8859-1 In-reply-to: Your message of "Fri, 19 Dec 2003 12:50:53 +0800." Date: Fri, 19 Dec 2003 21:37:39 +0100 Message-Id: <20031219203744.6CE0AC5F5F@atlas.denx.de> Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: In message you wrote: > > Now we are using a mpc823 embedded system, and there is some trouble. > We need to use SCC3 UART to control RS485 tranceiver. TXD3 is connected > to RS485 tranceiver's D pin, RXD3 is connected to RS485 tranceiver's R > pin, and RTS3 is connected to RS485 tranceiver's RE# and DE pin. Then > when transmitting data, we hope RTS3 signal can keep low to enble D. > When receiving data, we hope RTS3 signal can keep high to enble R. > So my question is, how can I program to control RTS3 signal in ppclinux. You will need a version of the UART driver that supports hardware handshake and allows you to configure the processor pins for handshake operations. See for example the source trees on our CVS server. Best regards, Wolfgang Denk -- Software Engineering: Embedded and Realtime Systems, Embedded Linux Phone: (+49)-8142-4596-87 Fax: (+49)-8142-4596-88 Email: wd@denx.de Q: Why do mountain climbers rope themselves together? A: To prevent the sensible ones from going home. ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/