On the M10x, DTR is hardwired to the RS232 interface chip so you can't control it. I think the only way to control RTS is directly through the UART. I control the RTS by closing the port when I don't want the control line active. (your mileage may vary)
----- Original Message ----- From: "Morgan Demers" <[EMAIL PROTECTED]> Newsgroups: palm-dev-forum To: "Palm Developer Forum" <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Friday, October 04, 2002 12:03 AM Subject: Need Help Using RTS or DTR as a control line below 2400 baud > Hi all, > > I'm working on a senior design project for school which involves the > wireless communication of 2 palm devices. I'm using the UART of the palm to > handle the communications. They lines are fed through a MAX232 transceiver > and then to the wireless hardware (a transmitter and receiver). > > Everything works fine, except the MAX232 inverts the signal such that > 0's are high and 1's are low (only way for the receiver to know what really > is a 0 or a 1, since rs232 has +Vcc for high and -Vcc for low). > > My problem is that the transmitter is now always on, even when I'm not > actually sending data. I need another control line to actually turn the > transmitter on during a transmission and off otherwise. > > Since I have the baud set to 1200, I don't need to use hardware flow > control, so I'm looking to use RTS as a control line. I've been trying to > find code (either using the API or with assembly) to actually do this, but > I've been unsuccessful thus far. > > I can guarantee that the hardware and software will only be used with > m100 palms, so compatibility with later devices isn't an issue (using > assembly to directly manipulate the RTS or DTR line for the m100 > specifically would work in my case). > > I have also tried to use the built in API function SrmControl with the > "srmCtlSetDTRAsserted" opcode. I'm passing it a boolean variable set to > "false" after I open the serial port with "SrmOpen". Unfortunately when > probing the DTR line I still get +6V, expecting ~+3V when the line is off > (not asserted). If anyone has tried to manually assert the DTR line low or > high before, please let me know - since I need +5V to operate the wireless > transmitter, I can use the DTR line to effectively turn the wireless > transmitter on and off also. > > Once again, this is for a senior design project, it's our only hold up > and we have a couple weeks left. Any suggestions, links to reference > documentation for the m100 hardware or more info about the palmOS 3.5 api > would be a great help. If anyone has source code related to controlling the > DTR or RTS line manually that would be awesome. > > Thanks for taking the time to read this, > Morgan J. Demers > > > -- > For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/ > -- For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/
