Design Reference Information 



Because the manufacturers of these sites change their web-sites so frequently it is impossible for us to keep these links up to date.

The hope is that our customers are smart enough to simply go to the manufacturers web-sites, and search for the component part numbers.

Please do not send us email regarding these links.

Component Links:

Cypress AN2131QC EzUSB micro-controller (8051 core).

The following web-page contains links for two files.

One is the TRM (technical reference manual) for the EzUSB (the component on my board).

The other is a huge zip file (file size is about 60MB). This zip contains the software and documentation for Cypress's own development board. The file includes examples for utilities, drivers, and firmware (including source code for all). It also includes an evaluation version of the Keil 8051 tools.

MicroChip 24LC128 serial eeprom (16KB, I2C interface).

Micrel 2920A-3.3BS LDO regulator.


Mechanical Information:

The following dimensioning is applicable to the revision "B" USB-I2C/IO board.

Hold the board such that you are looking at the components, USB connector at top, J1 to the left, J4 to the right, J2 at the bottom.

The corner at the bottom left is the origin (0.00, 0.00).

The corner at the upper right is the maximum point (3.000", 2.250").

Mounting holes:

0.150", 0.150"

0.150", 2.100"

2.850", 0.150"

2.850", 2.100"

The mounting holes use a 0.225" pad, with a 0.125" drill.


Pin 1 of J1 (bottom left, square pad) is at 0.150", 0.900".

Pin 1 of J4 (upper right, square pad) is at 2.850", 1.300".

Pin 1 of J2 (bottom left, square pad) is at 0.700", 0.150".

J1, J4, and J2 all are 0.100" pin spacing. I used a 0.060" pad, with a 0.042" drill.

Jumper Headers:

Pin 1 of JP1 (square pad) is at 1.900", 2.0125".

Pin 1 of JP2 (square pad) is at 2.275", 0.475".

Pin 1 of JP3 (square pad) is at 2.250", 1.100".

JP1, JP2, and JP3 all are 0.100" pin spacing. I used a 0.060" pad, with a 0.042" drill.

As I have stated on the web-page, the signals on the debug and I2C connector have not moved, but the pin-numbering has changed. That means... if you point at a pin on a Rev. "A" board... and point at the pin in the same physical location on a Rev. "B" board, the signal on that pin will be the same on both boards, but the pin number on the schematic and on the artwork may be different.


Connector Information:

The 5 pin connectors used are part of the AMP MTA-100 series.

The header (used on the board) is DigiKey part number A19471-ND.

The mating connectors are A19053-ND (for AWG28 wire) or A19021-ND (for AWG24 wire).

There are also strain reliefs, dust covers, spare pins, and crimping tools available.

A19233-ND (strain relief)

A19253-ND (dust cover)

A19313-ND (spare contact, AWG28)

A19312-ND (spare contact, AWG24)

59803-1 (inexpensive T-handle insertion/crimp tool)

58246-1 and 58074-1 (set of pieces for a much nicer insertion/crimping tool, hand actuated, auto-feed, much more expensive).

All you really need to buy is the mating connector... and maybe an insertion/crimp tool. The other items are optional.

The information for the 34 pin header, mating socket, and strain relief is as follows:

The manufacturer is "3M" and the manufacturer's part number (for the header on the board) is 2534-6002UB.

I buy the header and the mating connectors from DigiKey, the following list uses DigiKey part numbers.

MHB34K-ND, 34 PIN HEADER (this is the header mounted on the USB-I2C/IO board)

MKC34A-ND, 34 PIN SOCKET (this is the mating connector)

MKSR34-ND, STRAIN RELIEF (this is an optional strain relief for the mating connector)