Firmware for serial EEPROM It simply puts USB OUT transfers to the OUT port,
and answers to IN transfers. ECP are EPP are simulated too.
The driver for Windows you can get from
page above, and usage hints too.
Known PCB bugs and annoyances
This wiring is unable to read level on control lines
(i.e. cannot detect short circuit or intended ground connection of
pulled-high open-colloector output [as defined in SPP mode]),
cumbersome firmware programming
Cumbersome deactivation of EEPROM (in case of accident)
Bad placed components for housing, LED justification difficult
Pads for USB chip too small for hand-soldering
Cut-out for USB receptacle cannot be milled
External downloads for production
If you decide to build this device, you have to download a development kit for the
The data sheet is not necessary, but useful to understanding.
External downloads for modifications
For recompilation you need
und the complete
(»Operating Systems«, $699).
If you want to sell the device, you have to request a
USB Vendor ID
(and pay for it! $2500) and to modify drivers and firmware.
How to build
At first place all SMD components, then thru-hole and edge-mount
Three bigger components mus be bent to be flat, the crystal,
maybe tantalum capacitor.
The USB “B” receptacle stays in the middle of the housing.
Because there is no edge-mounting component available, this component
is used instead and must be soldered at the left and right metal plate.
It is recommended to use some sort of justification tool.
When you are complete, you test the circuit with "EZUSB Control Panel" from
(Windows should request a driver; you satisfy it by supplying the driver
from the Cypress development kit.)
With Cypress' “EZUSB Control Panel” you write the following
firmware into the serial EEPROM.
No programming device is needed!
Start "EZ-USB Control Panel" (EzMr.EXE) from start menu (installed by
Cypress' development kit)
Give him the file
Stand by!! About 20 seconds.
While prototyping, it is sufficient to leave the serial EEPROM unprogrammed;
you may even decide not to have an EEPROM at all.