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+====== GCA_PI08 16 channel module with max 40V 100 mA output per channel ======
+[[english|{{  rocrail-logo-35.png}}]][[:rocnet:rocnetnode-en|{{ :rocnet:rocnet-hw.png}}]]
+[[english|Content]] -> [[hardware-en|Hardware]] -> [[hardware-en#raspberry_pi_rocnet|GCA-RasPi]]
+  * [[GCA1-PI01-en|GCA-PI01]] | [[:rocnet:pi01can-en|Pi01CAN]] | [[GCA_PI02-en|GCA-PI02]] | [[GCA-PI03-en|GCA-PI03]] | [[:gca-pi04-en|GCA-PI04]] | [[:gca-pi05-en|GCA-Pi05]] | [[:gca-pi06-en|GCA-Pi06]] | [[:GCA-PI07-en|GCA-PI07]] | **[[:GCA-PI08-en|GCA-PI08]]** |  [[:gca107-en|GCA107 Relay board]] | [[:rocnet:rocdisplay-en|RocDisplay]] | [[:rocnet:fastclock-en|Fast Clock]]
+  * [[mgv-overview-en|The GCA modules]]
+  * [[:rocnet:rocnetnode-en|RocNetNode]]
+ \\
+^^^^By Peter Giling ^^^^
+[[http://raspberrypi.org|“Raspberry Pi" is a trademark of the Raspberry Pi Foundation.]]\\
+ \\
+===== Description =====
+NXP created several high current output chips for I2C\\
+Unfortunately, these chips are all only available in TSSOP shape, \\
+which makes doityourself very difficult.\\
+Since GCA always have been trying to make all kits really simple to build, this chip was no option this way.\\
+{{  :gca:pca9622_pict_01.png|}}So this was ordered on a small factory made and assembled pc board.\\
+A next nice feature of this chip was the built-in I2C driver, so no extra driver chip was needed, as used on other GCA_PIxx boards.\\
+On board, there is space for two led bars, to indicate the functioning of each ouput.\\
+These leds do not needed installation if you see no purpose there.\\
+The resistor arrays RP1 and RP2 need to be adapted to the voltage as supplied to the GCA_PI08, \\
+so these arrays will be mounted in sockets, making it simple to change if needed.\\
+Also, because of the hight Voltage of 40V max, each port can drive a large serial train of leds, using only one \\
+serial resistor in each chain.\\
+Each port can drive up to 100 mA max.\\
+The GCA_PI08 is part of the RocNet network, Rocrail provides of course all the setting options that are needed.\\
+See: __**[[:rocnet:rocnetnode-led-en|RocNetNode Pi08 LEDs]]**__ .\\
+The GCA_PI08 has a connection J3 \\
+   * for power in of max 40 V dc (V+, V-)
+   * and (OE+, OE-) to connect an external switch to disable all ports.\\
+When not used OE+ and OE- should be bridged with a short piece of wire.
+The connection of ports can be done in various ways.\\
+First of all there are two PSS 254 connectors, quit familiar in GCA kits.\\
+Instead of that, also a AST 021-10 connector will fit instead of PSS 254.\\
+Here you can simply connect wires without the need of a screw driver.\\
+And all outputs are also available on a 20 pin flatcable header.\\
+This poor quality type of connector is not really favorite inside GCA boards, but is possible anyway.\\
+|  {{:gca:gca_pi08_pict_01.png?500}}  |  The drawing of version 1 69 x 63 mm board.  |\\
+The standard used PSS 254/PSK254 connectors might be not the first choice of many railroaders, but consider that this connector\\
+can handle a current of at least 1,5 amp att each pin and is very rigid.\\
+All you need to buy is a crimping tools, available from GCA for € 20.\\
+Once you have that settled, you can easily make you own cables in any length with the use of 0,25 mm wire.\\
+The kit will be delivered with standard PSK connectors.\\
+In stead of PSK connectors, as delivered in the kit,  also the more costly AST021 connectors can be mounted.\\
+Another, rather expensive option is a 10 pin detachable connector WAGO type MCS. (known for example from Intellibox rail connection)\\
+It will also fit instead of PSS 254 connectors.\\
+The position of the led bars is the next possible option.
+In this place, a standard 2x8 pins boxheader will fit.\\
+The resistor array keeps its place, so you do not need any addional resistors.\\
+Using boxheaders here also has the nice advantage , that short circuit of any output does not do much harm.\\
+The outside pins of the boxheader are the + for the connected leds, the inside pins are minus.\\
+Please keep in mind to adapt the input power to the amount of leds that is connected to each oupput.\\
+For example do not use 30V power when only one led is connected to each output.\\
+It will result in too much heat in the resistor array!\\
+\\
+==== How to find out which pcb I have? ====
+\\
+On version 1.x there is no C3 nor R3.\\
+\\
+===== The version 1 hardware files =====
+|  {{:gca:gca_pi08_sch.pdf|The schematic drawing}}  |
+|  {{:gca:gca_pi08_pcb.pdf|The pc-board and parts positions}}  |
+|  {{:gca:gca_pi08_gerber.zip|Gerber files for pcb}}  |
+|  {{:gca:gca_pi08_parts.pdf|Bill of materials}}  |\\
+\\
+===== Version 2 =====
+In the first edition, it was possible to damage the PC9622 chip, when suppply was changed from 15 to 5 Volt.\\
+To avoid that, v2 has an extra capacitor.\\
+\\
+|  {{ :gca:gca_pi08_v2_sch.pdf  |  The schematic drawing  }}  |
+|  {{ :gca:gca_pi08_v2_pcb.pdf |The pcb and parts positions}}  |
+|  {{ :gca:gca_pi08_v2_parts.pdf  |  The bill of materials  }}  |
+\\
+===== Important warnings for version 1 ! =====
+If you are using external power to be connected to J3, please be sure that this power is 100% isolated from anything else.\\
+It seems that some power supplies, for example, have their low voltage output connected to ground via the mains sockets.\\
+Where also your PC is grounded that way, serious damage on PI08 pcboard or elsewhere in the RocNet circuit might be initiated.\\
+Be sure of that before you connect it! \\
+There was no reasonable easy and payable way to make a galvanic isolation between RocNet and board PI08.\\
+The first goal in developing this unit was to create something that is not too expensive.\\
+Therefore ground level of RocNet and ground of J3 on PI08 are linked together.\\
+Another issue has occurred with practical test, which never have been realised here in my workshop.\\
+If you connect external power to J3, and later on you deside to switch back to 5V supply for the leds, \\
+it appears that capacitor C2 is fully charged.\\
+Since there is no more drain for that capacitor, it will put the full charge into the 5V circuit,which will destroy the PCA9622 immediately.\\
+Version 2 has a protection for that.\\
+An option for version 1 is to fix a resistor of +/- 10 KOhm between the + and - of the large Elco.\\
+Just fit it at the bottom side of the pcb.\\
+\\
+===== Jumper JP1 en power supply =====
+The on-board chip is connected to 5 V of the RocNet bus.\\
+But the common anode of all leds to be connected are seperated from that.\\
+With JP1 it is possible to select a n external supply (coming from J3),\\
+or the 5V from the RocNet bus.\\
+Indication on board shows the right settings for this jumper.\\
+\\
+:!: **In version 1 it must be absolutely certain that during operation the jumper between pin 2 and 3 may only be connected when capacitor C2 is discharged beforehand.\\
+In version 2 that action is protected.
+** :!: \\
+===== Total possible led outputs in one RocNet setup =====
+The PCa9622 is configured to be adressed from &H060 to &H06F.i.e. 16 modules.\\
+Since each chip  is controlling 16 Led outputs, the total amount is 256 Led outputs in this RocNet.\\
+\\
+===== Adressing the PCA9622 chip. =====
+{{  :gca:gca_pi08_pict_03.png?300|}}
+This board comes , as from factory, with all adresses left open.\\
+The picture shows the four adresses connected to 0V meaning that this chip is addressed to &H060.\\
+Logic '1' to be selected by connecting the two top pads of the correspondent number, instead of the bottom two.\\
+^  Address settings  ^^^^^^
+|  Address  |  A0  | A1  | A2  | A3  |  Leds #  |
+| | | | | | |
+|     60     |  0  |  0  |  0  |  0  |  1..16  |
+|     61     |  1  |  0  |  0  |  0  |  17..32  |
+|     62     |  0  |  1  |  0  |  0  |  33..48  |
+|     63     |  1  |  1  |  0  |  0  |  49..64   |
+|     64     |  0  |  0  |  1  |  0  |  65..80   |
+|     65     |  1  |  0  |  1  |  0  |  81..96   |
+|     66     |  0  |  1  |  1  |  0  |  97..112   |
+|     67     |  1  |  1  |  1  |  0  |  113..128   |
+|     68     |  0  |  0  |  0  |  1  |  129..144   |
+|     69     |  1  |  0  |  0  |  1  |  145..160   |
+|     6A     |  0  |  1  |  0  |  1  |  161..176   |
+|     6B     |  1  |  1  |  0  |  1  |  177..192   |
+|     6C     |  0  |  0  |  1  |  1  |  193..208   |
+|     6D     |  1  |  0  |  1  |  1  |  209..224   |
+|     6E     |  0  |  1  |  1  |  1  |  225..240   |
+|     6F     |  1  |  1  |  1  |  1  |  241..256   |
+==== a small correction needed ====
+It appears that version 1 circuits are missing the internal ground connection with the two RJ12 connectors\\
+That can easily be solved with the short wire bridge marked in this picture:\\
+{{:gca:ground_patch.png?300}}