USB转并口的资料

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http://www-user.tu-chemnitz.de/~heha/bastelecke/Rund%20um%20den%20PC/USB2LPT/index.html.en

USB2LPT – Cloning instructions for Release 1.6

This device is almost the same as Release 1.5.
For high-speed USB, there is a Release 1.7.

If 3.3V operation of ATmega is wanted, a user can now populate a dual diode BAV199 instead of the LD1117 of the previous version. This enables drawing less than 500 µA of standby current in this case.

Electronic Components

You need:

Pieces	Description	Reichelt Order Code	Price in € (2007)
1	ATmega8 in TQFP32 package	ATMEGA 8-16 TQ	1.70
1	Ceramic capacitor 100 nF 0603	X7R-G0603 100n	0.051
1	Resistor array 220 Ω 1206	BCN16	0.02
1	Resistor 10 kΩ 0805	SMD-0805 10k	0.10
1	Electrolytic capacitor 10 µF	rad 10/35	0.041
1	Yellow LED 3 mm	LED 3mm ST ge	0.051
1	SubD receptacle 25 pin	D-SUB BU 25	0.15
1	USB receptacle MiniB through-hole	USB BWM	0.50
1	Housing	Kappe CG25G	0.13
1	USB cable 1 m	AK 673-A	0.98
1	Two-sided PCB (see below)	UL16LP	1.00

It's not hard to populate this PCB.

 
(Sufficiently) populated PCB

The LED

The yellow multi-function LED shows following states:

• off:
  • No power supply (cable broken or similar)
  • USB2LPT not recognized by computer
  • USB Standby mode - e.g. at notebook's suspend mode
  • USB2LPT in bootloader mode
• on:
  • USB2LPT active, output drivers enabled, inputs with pull-up resistors
• flashing:
  • fast: USB BULK or INTERRUPT transfers (redirected IN and OUT instructions; normal operation)
  • slow: USB CONTROL transfers (mostly initiated by Windows)

Software

• Schematic and PCB, Source
• For Windows driver and AVR firmware, see page above, and how-to-use instructions.
  Here you can browse the firmware source in your web browser.

Preparations

• Drill holes into SubD shell for LED
• Label the shell
• Bend pins of USB receptacle straight – see picture
• Trim pins of LED and electrolytic capacitor to about 1 cm length
• Download and install either 　 PonyProg2000 or WinAVR
• PonyProg2000: Setup interface as shown here, check by connecting the programming adapter (this checks for connection between Pin 2 and Pin 12), invoke Setup→Calibration

Making-Of

• put SMD cream, 4 SMD components, make a reflow process – or solder by hand
• Check for short circuit between 5 volts and ground
• press and solder SubD receptacle keeping ½ mm gap between PCB and SubD shroud
• Align and solder USB receptacle (see helper tool), solder the pins with lowest possible iron temperature
• Populate electrolytic capacitor as flat as possible
• Align and solder the LED using the shell, watch for right polarity
• Check for short circuit between 5 volts and ground again
• Check "operation" by connecting the USB cable, must show as "inoperational USB device", this is the power supply for programming the bootloader
• Connect programming adapter to an old-style parallel port and program the bootloader, either
  • PonyProg2000: load main.hex, write, set fuses exactly as shown here
    Do not twiddle with the fuses without knowledge! You may make the ATmega unaccessible to PonyProg2000 and all other low-voltage serial programmers!
    or
  • WinAVR: invoke make prog (directory src/firmware/USB2LPT6/bootloadHID)
  If your programming software doesn't recognize the right controller, check:
  • Programming adapter soldered correctly?
  • Programming adapter used in correct direction?
  • Solder jumper SJ2 (still) connected?
  • Pins of SubD25 socket soldered correctly?
  • Microcontroller soldered in correct alignment and angle? (If wrong, remove with a hot-air gun. If 180° wrong, use new ATmega8.)
  • Mikrocontroller soldered without shorts?
• Cycle power to USB2LPT, let install driver usb2lpt.inf. The Bootloader ( HIDboot) will not occur bevause the .hex file above contains both bootloader and the real USB2LPT firmware.
  If there is no USB2LPT, then check:
  • Solder joints on USB socket correctly?
  • USB socket not melted? (Contact springs still visible?)
  • SMD solder joints correctly without shorts?
  Check with another computer and/or with front-side or back-side USB connectors on PC, or using a USB hub. If USB2LPT seems to work unreliable, populating the crystal and downgrading to USB2LPT 1.5 firmware may help. The reason is an unstable 5V supply, that jitters the internal RC oscillator of the 1.6 firmware solution.
• Remove programming adapter
• Scratch jumper SJ2 (the only solder jumper on silk-screen-less lower PCB side)
• Connect LPT checker or similar device, run Kurzschlusstest.exe, make corrections if necessary
• Close shell, make a final check

Known PCB bugs

• The crystal and the both 22 pF capacitors are not to populate
• Population with ATmegaX8 is currently not recommended.
  If you want ATmega48 population, R₁ should be 4.7 kΩ, and the older firmware USB2LPT5 (and crystal) must be used. A bootloader cannot be used (this chip has no bootloader support)
• If D₂ (BAV199) is used, R₁ must be 1.5 kΩ

Solder jumpers

This revision 6 (USB2LPT 1.6) has 3 pre-connected solder jumpers:
    SJ1 can assign power to pin 25 of SubD receptacle:

• open: Pin 25 unbeschaltet
• right connected: Pin 25 to ground (default)
• left connected: Pin 25 to 5 volts

If power is needed, populating a self-resetting fuse is highly recommended.

• SJ2, connected at PCB fabrication, scratched at device manufacturing: activates the RESET pin of ATmega for programming the microcontroller.

• SJ3, connected by default, scratch when you want 3.3 volts operation of ATmega8 (e.g. for safer JTAG connection), populate a BAV199 and change R₁. Moreover, scatch it to measure device's current consumption and re-solder.

USB2LPT – Cloning instructions for Release 1.7

Electronic Components

Almost identical to Release 1.4. Except voltage regulator:

instead	now	GND current	output current	options	attention
LD1117S33	TPS79733DCK	1,3 µA	50 mA (190 mA typ.)	PowerGood output	Populate C4
	TPS71533DCK	3,2 µA	50 mA (125 mA min.)	–
	TPS71433DCK		80 mA (100 mA min.)
	TPS77033DBV	17 µA	50 mA (340 mA typ.)	inverse enable input (not used here)	Do not populate C4! Instead, populate electrolytic or tantalum capacitor 10 µF into two holes beneath C4. This is because ESR must have a minimum for stable operation.
	TPS78833DBV		150 mA (350 mA typ.)
	TPS76933DBV	18 µA	100 mA (350 mA typ.)

Values in parentheses are for internal current limitation

The overall current consumption of this device in USB idle state should now be about 500 µA, as required by USB specification.
(The EZUSB-FX2 chip itself contributes 500 µA:-)

Populated PCB. The capacitor C4 is exceptionally populated with an SMD tantalum capacitor

Software

• Circuit Diagram and PCB Silkscreen, Source for PCB software Eagle

• Firmware same as Revision 1.3

Solder Jumper

Same as for Revision 1.4.

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