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product:usb2ax:specs [2013/04/01 05:32] xevel |
product:usb2ax:specs [2014/02/05 17:19] xevel |
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The hardware of the USB2AX is relatively simple: only 17 components and a 16x20mm PCB. | The hardware of the USB2AX is relatively simple: only 17 components and a 16x20mm PCB. | ||
- | 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. | + | {{product:usb2ax:USB2AXv31_front_euro_s.jpg}} |
- | The USB2AX v3.1 has a double LED (Red/Green), ESD protection on both connectors (USB and | + | 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). | ||
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+ | 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 a 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 a 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: 16mm 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)]] | ||