Table of Contents
DCC232
Content → Command Stations → DCC232
Introduction
All personal computers now days have plenty of power free for doing much more then only show and control a model train layout.
Generating a digital signal for mobile and stationary decoders is one possibility to use this potential.
The DCC232 library is a lightweight DCC only generator for boosters like the ORD-3.
DCC signal is generated using a serial device.
Legacy RS232 devices and many USB-RS232 converters are supported.
Advantages
- very low CPU load
- no command station needed (third party firmware)
- complete control of the process
- only modem privilege is needed for accessing the serial device
- runs under Windows and Linux
Disadvantages
- The generated DCC signal does not fully conform to the NMRA standards; Some decoders will not operate or only partial.
- No service mode programming. (PT)
Features
- 128 loco slots
- auto purging
- 14, 28 and 128 speed steps
- short and long loco addressing
- 28 mobile decoder functions
- Operations Mode Programming (Ops, POM)
- Write
- Read; needs a RailCOM cutout booster and detector
- stationary DCC decoders
- short circuit checking
- ORD-3 support
Tests
Ubuntu 10.10
| PC | Device | Chip | Result | CPU % |
|---|---|---|---|---|
| Intel Pentium Dual Core 1.73GHz 1GB | /dev/ttyUSB0 | PL2303 | OK | 0…2 |
| Intel Pentium Dual Core 1.73GHz 1GB | /dev/ttyUSB0 | FTDI | OK | 0…2 |
| Intel Pentium Dual Core 1.73GHz 1GB | /dev/ttyUSB0 | DELOCK Serial HUB | UNSTABLE | 0…2 |
| Intel Atom 1.6GHz 1GB | /dev/ttyS1 | Legacy | UNSTABLE; super user only | 0…2 |
Raspbian
| PC | Device | Chip | Result | CPU % |
|---|---|---|---|---|
| Raspberry Pi Rev. B | /dev/ttyUSB0 | PL2303 | OK | 1…4 |
| Raspberry Pi Rev. B | /dev/ttyUSB0 | FTDI | OK | 1…4 |
Windows XP
| PC | Device | Chip | Result | CPU % |
|---|---|---|---|---|
| Intel Celeron 300MHz 256MB | com1 | Legacy | OK | 0…3 |
Mac OS X 10.6
| PC | Device | Chip | Result | CPU % |
|---|---|---|---|---|
| Intel Core 2 Duo 2.26GHz 8GB | /dev/tty.usbserial-ftEHGJCX | FTDI | Slow reaction.(4 sec.) | 2…3 |
| Intel Core 2 Duo 2.26GHz 8GB | /dev/tty.PL2303-00001004 | PL2303 | No valid DCC signal | 2…3 |
| Intel Core 2 Duo 2.26GHz 8GB | /dev/tty.MCS78XX_Port0.0 | DELOCK Serial HUB | No valid DCC signal | 2…3 |
Setup
Only the IID and the serial port has to be set, the rest is optional.
Device
Port
The device name of the serial port to use with DCC232.
Commonly used devices:
| OS | Legacy RS232 | USB |
|---|---|---|
| Linux | /dev/ttyS0, /dev/ttyS1 | /dev/ttyUSB0 |
| Mac OS X | - | /dev/tty.*¹ |
| Windows | com1, com2 | com7 |
| RasPi | /dev/ttyAMA0 | /dev/ttyUSB0 |
¹) Manufacturer dependent.
Slot management
Purge
Remove idle mobile decoders, using the purge time, from the slot after the velocity is zero.
No DCC refresh packets are generated for this address after purge.
Purge time
The number of seconds a mobile decoder must be idle before it is purged.
Idle = stalled.
Short circuit checking
Active
Activate the short circuit checking on the DSR line in a separate watchdog thread.
Invert DSR
Invert the short circuit signal connected to the DSR line of the RS232 interface.
This option must be set in case the ORD-3 is used as booster.
Delay
The time in milliseconds the short circuit must resist before the Rocrail server is informed of a short circuit.
PT
fastcvget
Usable in cases of an old native RS232 interface, to get a fast reading of the CV's.
- Note: With very many of USB-RS232 converters, the reading CV's is not possible, because the RI connection of the RS232 (pin 9) is not supported.