User Tools

Site Tools



This shows you the differences between two versions of the page.

Link to this comparison view

gca174-en [2019/01/03 16:22] (current)
phg created
Line 1: Line 1:
 +====== GCA174 DCC/​Motorola decoder for GCA145 ======
 +[[:​english|{{ ​ rocrail-logo-35.png}}]]
 +[[:​english|Content]] -> [[:​hardware-en|Hardware]] -> [[:​hardware-en#​interfaces|GCA]]
 +  *  [[:​mgv-overview-en|The GCA modules]] ​
 + \\
 +^^^^By Peter Giling ^^^^
 +===== Direct decoder for Motorola or DCC =====
 +This board is based on the design of\\
 +The firmware , copyright of,​ is available at http://​​bau_led/​led_schalten.htm#​download\\
 +This board is only attachable to J5 of GCA145/​MGV145.\\
 +It features the 7 outputs, needed to select position 1..48 on GC145/​MGV145.\\
 +Also an isolated feed-back is provided.\\
 +Feed-back is free to be used with systems like S88.\\
 +The on-board opto-couplers isolate the didital rail signals and feed-back from the board.\\
 +Feed-back is very nice inside Rocrail environment,​ because it can signal Rocrail to start a train AFTER the selected postion has been reached.\\
 +===== The prototype =====
 +|   ​{{:​gca:​gca174_pict_02.jpg?​600 ​ }}  |  The board with opto-couplers \\ ready to be connected to GC145  |
 +===== Hardware files of protoype =====
 +{{:​gca:​gca174_sch.pdf|The schematics}}\\
 +{{:​gca:​gca174_pcb.pdf|The pc-Board and parts positions}}\\
 +{{:​gca:​gca174_parts.pdf|The bill of materials}}\\
 +===== The final board design =====
 +|  board in production, coming in short term  |
 +===== Hardware files for final GCA174 design =====
 +|  {{:​gca:​gca174final_sch.pdf|The schematic drawing}} ​ |
 +|  {{:​gca:​gca174final_pcb.pdf|The pcb and parts positions}} ​ |
 +|  {{:​gca:​gca174final_parts.pdf|The bill of materials}} ​ |
 +===== Address selection =====
 +Basicly, the firmware from comes with adress ​ 1..7.\\
 +By pressing the button, the decoder is in learning mode, showing D1 to flash.\\
 +All you have to do now, is sending the first address from your central unit.\\
 +After that, just pwer off GCA145 and power on again.\\
 +The addresses of the next ports will be automaticly set in following sequence\\
 +One other option is to download hex_minipu from this page: http://​​bau_pic/​hexmanipu.htm#​download .\\
 +It will give you the option to directly change adresses and store them, before programming the chip.\\
 +===== Feed-back =====
 +GCA174 has a feed-back signal, to inform Rocrail that turntable is ready to move trains on/off.\\
 +This feed-back signal is electrical (galvanic)isolated from the GCA174.\\
 +By connecting J2 pt 1(-) and 2(+) to any device like S88 units or derivates,​\\ ​
 +Rocrail will receive this port condition.\\
 +Settings in Rocrail , see Position sensor
 +===== Led signals =====
 +GCA174 is priovided with 6 yellow leds for indication of decoded turntable position.\\
 +The red led(D7) shows the write signal ( in Rocrail, look for 'new Position Flag' ), to inform GCA145 to start responding on the given position.\\
 +===== Connections of GCA174 =====
 +===== Extra modification on GCA145(MGV145) =====
 +GCA174 needs 5 Volt which is by default not available from J5 on GCA145.\\
 +Therefore, this diode 1N4003 (or equivalent) should be mounted under J5 as this picture shows.\\
 +**NOTE:** The latest green pcb has this diode(D10) on board, so no further attention needed.\\
gca174-en.txt ยท Last modified: 2019/01/03 16:22 by phg