User:JanosA

I am IP Network and Datacenter engineer, currently I'm working for an Internet Service Provider in Hungary.

My hobby is programming embedded systems and creating my own small electronic boards.

Skills

• Assembly programming: PIC 8bit family
• C programming: PIC 8bit / PIC32MX family, Linux
• Perl, PHP, Javascript, Html programming with MySQL
• Linux system administration
• RS-232/485 serial communications: Ascii, Modbus, Saia Sbus, etc.
• IP networking

My ArmadeuS plans (APF28 based)

• Creating an universal home automation hardware for my friends, with easy programming in perl or PHP. :)
• Datacenter temperature monitoring, with RS-485 and OneWire communications.
• Data logger for Saia Sbus based intelligent power meters.

RS485

Mini HOWTOs for my APF28/iMX28 mxs-auart and busybox stty patches.

• Setup APF28 serial port for RS485 communication:

# stty -F /dev/ttySP0 raw
# stty -F /dev/ttySP0 -echo -echoe -echok
# stty -F /dev/ttySP0 rs485

• Set extra delays for TXEN/RTS signaling before and after the transmitted packet (in microseconds):

# stty -F /dev/ttySP0 rs485delaybefore 100
# stty -F /dev/ttySP0 rs485delayafter 100

• To get current RS485 parameters. (If the port device supports the RS485 options you will see the last two lines)

# stty -F /dev/ttySP0
speed 9600 baud; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>;
eol2 = <undef>; swtch = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R;
werase = ^W; lnext = ^V; flush = ^O; min = 1; time = 0;
-brkint -imaxbel
rs485 -rs485rtsonsend -rs485rtsaftersend -rs485rxduringtx
rs485delaybefore = 100; rs485delayafter = 100; rs485delaylastchartx = 1250;

Please note:

• You can't set the "rs485delaylastchartx" parameter, it's calculated automatically from the baudrate.

Special notes only for APF28/iMX28 mxs-auart driver:

• All delays are in microseconds.
• The "rs485delaylastchartx" parameter is not used in DMA mode.
• The parameters: "rs485rtsonsend" "rs485rtsaftersend" "rs485rxduringtx" are not used.