This board adapts the GPSDO diagnostic port to USB. You get to select whether to transmit the diagnostic output or the GPS NMEA output. PPS is sent to DCD, and is positive-oriented (that is, DCD asserts on-time). The USB interface is a CDC device. Open it and set it for 9600 baud 8N1.

The SSOP chip is a CY7C65213. The SOT23-5 chip is a single inverter. The USB connector is a microB one. The diagnostic connector is a CUI MD60S. The passives:

• R1 - 10kΩ
• R2 - 4.7kΩ
• R3 - 1MΩ
• C1, C2 - 0.1µF
• C3 - 1µF
• C4 - 2.2µF
• C6 - 4700pF

This board doesn’t work. It shorts out the power supply of the GPSDO. Don’t use it.

Use this one.

This board doesn’t work. It shorts out the power supply of the GPSDO. So don’t use it.

Use this one.

This board is an adapter for the AtmelICE programmer.

The AtmelICE is a very versatile in system programmer and debugger, but it has a couple of small drawbacks. It doesn’t supply target power at all, and the cable they supply to adapt to 6 pin 100 mil sockets is kind of fragile.

This board fixes both of those. You use a straight-through 10 pin 50 mil cable from the AtmelICE and then a standard 6 pin 100 mil cable to the target. Optionally, you can connect a USB cable up to the board and a jumper will select between injecting +5 volts or +3.3 volts (from an on-board LDO) to the target power line.

The pinout should work for ISP and PDI devices (ATTiny, ATMega and ATXmega).

This board allows you to connect a mini-DIN 6 cable from my GPS Disciplined Oscillator’s diagnostic port to the Raspberry Pi.

The correct part for the mini-DIN 6 jack is the CUI MD-60S. The 3 pin jumper block selects the serial input on the pi to be either the GPS NMEA sentence output or the diagnostic output. The transmit output of the Pi is always connected to the GPS RX pin on the GPSDO. The PPS output of the GPSDO is fed into GPIO 18. The two pin jumper sets whether or not the 5 volt pin from the diagnostic header is connected to the 5 volt bus of the Pi. Powering the Pi from the diagnostic connector is only recommended for the FE-5680A breakout board. Added 5 volt load on the OCXO or TCXO may impact its stability. Attempting to power the oscillator from the Pi is NOT recommended.

Mount a 2x8 .1" DIP female header on the bottom of the board. Install the board on the Pi GPIO header at the left most (pin 1) end. The mini-DIN 6 cable should exit more or less right over the SD card.

The two diodes are just 1N4148s and the two resistors are 10 kΩ.