> Date: Wed, 10 Jan 2007 11:13:44 +0100 > From: Txema Lopez <[EMAIL PROTECTED]> > Subject: MPC5200B TxRTS auto-toggle mode. > To: [email protected] > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset="iso-8859-1" > > Hi all, > > I'm working in a MPC5200B based plataform. I want to use the TXRTS > feature of the MPC5200B's PSC-UART(auto toggle when the transmitter > ends) to manage a rs485 transceiver but I'm unable to do it. Googling, > I've found that a year ago Stefan Eletzhofer asked for the same > question, but I can't find any answer to this question (neither in the > linuxppc-embedded mailing list archives). Did anyone find a solution? Is > there a patch available for a Denx's 2.4.25 kernel?.
Maybe this is of interest for you - I got this answer from Freescale support after I asked a Freescale engineer at embedded world fair in Nuremberg: Dear Mr. Moll, please find below answers to your question concerning RTS deassertion on MPC5200B PSC in UART mode. Basically it works that RTS is negated when the shift register of the PSC has transmitted the current data word. Please see also: >MPC5200B Users Manual Chapter 15.3.1.3 Transmitting in UART Mode >In applications in which the transmitter is disabled after transmission is complete and RTS is appropriately programmed, RTS is negated one >bit-time after the character in the shift register is completely transmitted. The transmitter must be manually re-enabled by reasserting RTS >before the next message is to be sent. However, this is based on a single data word to be sent. Data still residing in the transmit FIFO would remain there until the next transmission is initiated. Both, disabling and re-enabling of the transmitter has to be done manually. For your particular case it probably makes more sense to use the TxEMP interrupt of the PSC and deassert RTS manually in the interrupt service routine. (please see Table 15-28. Interrupt Mask Register (0x14) for UART / SIR Mode in the MPC5200B Users Manual) Unfortunately there is no MPC5200 App-Note or demo application for the use of EIA-485 available. _______________________________________________ Linuxppc-embedded mailing list [email protected] https://ozlabs.org/mailman/listinfo/linuxppc-embedded
