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product:usb2ax:specs [2013/04/01 05:32]
xevel
product:usb2ax:specs [2014/05/15 00:29]
xevel
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 ===== USB2AX: Technical Specifications ===== ===== USB2AX: Technical Specifications =====
  
-The hardware of the USB2AX ​is relatively simple: only 17 components ​and a 16x20mm PCB.+//This page is currently referring to v3.1a, ​and will be updated with infos for v3.2a shortly.// 
  
-At its core is an ATMega32u2, an USB-enabled 8bit MCU with 32KB of FLASH, 2.5KB of RAM and 1KB of EEPROM, running at 16MHz.+The hardware of the USB2AX ​is relatively simple: only 17 components ​and a 15x20mm PCB.
  
-The USB2AX v3.1 has a double LED (Red/​Green),​ ESD protection on both connectors (USB and + 
 +{{product:​usb2ax:​USB2AXv31_front_euro_s.jpg}} 
 + 
 +At its core is an ATMega32u2, an USB-enabled 8bit MCU with 32KB of FLASH, 1KB of RAM and 1KB of EEPROM, running at 16MHz. 
 + 
 +The USB2AX v3.1 has a double LED (Red/​Green),​ ESD protection on both connectors (USB and serial), 0.1" breakout pads for RST, GND, HWB and the 4 SPI pins (PB0 to PB3). 
 + 
 + 
 +To achieve Half-duplex operation on DATA, TX and RX are shorted together and the firmware alternatively turns ON the transmission or reception side of the MCU's UART. This is inspired by the [[http://​www.vanadiumlabs.com/​arbotix.html|Arbotix]].
  
 ==== Schematics ==== ==== Schematics ====
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 [[https://​paranoidstudio.assembla.com/​code/​paranoidstudio/​git/​nodes/​master/​usb2ax/​elec|All Eagle files]] [[https://​paranoidstudio.assembla.com/​code/​paranoidstudio/​git/​nodes/​master/​usb2ax/​elec|All Eagle files]]
  
-The protection circuitry for TX and RX comes from the [[http://​ruggedcircuits.com/​html/​ruggeduino.html|Ruggeduino]],​ and makes it possible to withstand applying 12V to DATA indefinitely, which can easily happen in real life with a shoddy custom cable, ​or damage cable.+The protection circuitry for DATA, with the zener diode and PTC resistor, ​comes from the [[http://​ruggedcircuits.com/​html/​ruggeduino.html|Ruggeduino]],​ and makes it possible to withstand applying 12V to DATA indefinitely. More detailed explanation of how it works [[http://​forums.trossenrobotics.com/​showthread.php?​5675-USB2AX-v3.1&​p=53101#​post53101|here]]. This situation ​can easily happen in real life with a shoddy custom ​or damaged ​cable, ​and improper protection could result in fried motherboard..
  
  
 ==== Bill Of Material ==== ==== Bill Of Material ====
  
-FIXME +^ #  ^ Ref. ^ Qty. ^ Description ​                                                ^ Part Value ^     ​Package ​   ^ 
- +| 1  | U1    | 1 | ATMega32u2 MCU                                                | ATMEGA32U2-MU | QFN-32 ​     | 
 +| 2  | Q1    | 1 | SMD 16MHz quartz ​                                             | 16MHz | CRYSTAL-SMD-3.2X2.5 |  
 +| 3  | USB1  | 1 | USB Type A Plug through hole                                  |          | USB-A-THT ​       |  
 +| 4  | DXL1  | 1 | Dynamixel Connector Right Angle                               | SPOX2.5-3WAY ​               | 
 +| 5  | C1    | 1 | USB decoupling capacitor ​                                     | 4.7µF ​   | C0603            |  
 +| 6  | C2,C3 | 2 | ATmega decoupling capacitors ​                                 | 0.1µF ​   | C0402            |  
 +| 7  | C4    | 1 | Capacitor for UCAP                                            | 1.0µF ​   | C0402            | 
 +| 8  | C5,C6 | 2 | Load capacitor for quartz ​                                    | 18pF     | C0402            |  
 +| 9  | R1    | 1 | USB line resistor array                                       | 22R      | 0402x2 ​          |  
 +| 10 | R3    | 2 | DATA line protection and current limiting resistor array for LEDs | 150R | 0402x2 ​          |  
 +| 11 | RPTC1 | 1 | PTC resistor for DATA overvoltage protection ​                 | 100R     | C0603            |  
 +| 12 | D1    | 1 | Zener diode for DATA overvoltage protection ​                  | 5.1V     | SOD-923 ​         |  
 +| 13 | LED1  | 1 | Double LED                                                    | Green/Red | C0603           |  
 +| 14 | U2    | 1 | ESD protection ​                                               | IP4282CZ6,​115 | XSON6         |  
 +| 15 |       | 1 | Heat-shrink tubing (diam:​12,​7mm)(length:​24mm+/​-1mm)(TRANSPARENT) |            |  |
  
 ==== Mechanical ==== ==== Mechanical ====
  
-Size: 16mm x 36mm x 7mm (without heat-shrink tubing)+Size: 15mm x 36mm x ~7mm (without heat-shrink tubing)
  
 [[http://​www.xevel.fr/​other/​usb2ax_v3.1.stl|3D CAD file (stl)]] [[http://​www.xevel.fr/​other/​usb2ax_v3.1.stl|3D CAD file (stl)]]
  
product/usb2ax/specs.txt · Last modified: 2017/07/27 08:04 by xevel