Shared projects

FTDI-be-gone RS - direct wire variant

2 layer board of 1.48 x 0.90 inches (37.5 x 22.9 mm).
Shared on December 24th, 2017 21:09

This is a version of my FTDI-be-gone RS-232 board, but with SSOP instead of QFN parts, and designed to be directly wired to a USB cable. Connect the signal/power ground pin of the USB cable to the GND pin and connect the cable’s shield to the SHLD pin of the USB connector (there is an RC circuit between the two designed to break ground loops but shunt AC to ground). Mount a PC pin DB9M on the edge of the board for the RS-232 connection.

  • IC1 - CY7C65213
  • IC2 - MAX3243ECDB
  • FB1 - 400Ω ferrite bead
  • C1-C4, C7 - 1µF
  • C5 & C6 - 0.1µF
  • C9 - 0.01µF
  • C8 - 10µF
  • C10 - 4700pF
  • R1 & R2 - 330Ω
  • R3 - 1MΩ
  • TX & RX - 0805 LEDS

NOTE: Both ICs have pin 1 oriented towards the bottom of the board.


FTDI-be-gone RS - direct wire variant

2 layer board of 1.48 x 0.90 inches (37.5 x 22.9 mm).
Shared on December 24th, 2017 21:09

This is a version of my FTDI-be-gone RS-232 board, but with SSOP instead of QFN parts, and designed to be directly wired to a USB cable. Connect the signal/power ground pin of the USB cable to the GND pin and connect the cable’s shield to the SHLD pin of the USB connector (there is an RC circuit between the two designed to break ground loops but shunt AC to ground). Mount a PC pin DB9M on the edge of the board for the RS-232 connection.

  • IC1 - CY7C65213
  • IC2 - MAX3243ECDB
  • FB1 - 400Ω ferrite bead
  • C1-C4, C7 - 1µF
  • C5 & C6 - 0.1µF
  • C9 - 0.01µF
  • C8 - 10µF
  • C10 - 4700pF
  • R1 & R2 - 330Ω
  • R3 - 1MΩ
  • TX & RX - 0805 LEDS

NOTE: Both ICs have pin 1 oriented towards the bottom of the board.



GPSDO<->232

2 layer board of 1.25 x 1.40 inches (31.8 x 35.6 mm).
Shared on December 24th, 2017 05:32

This board adapts the GPSDO diagnostic port to RS-232. 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 SOIC-16 chip is a MAX232. The SOT23-5 is a single inverter. All 6 caps are 0.1 µF. The edge-mounted DB9 should be a female. It can connect directly to a DB9M style serial port or cable. The diagnostic connector is a CUI MD60S. You use a straight-through mini-DIN-6 cable (like a PS/2 cable) to connect up to the GPSDO.

For maximum stability, you should keep this board connected permanently if you’re going to use it. Adding and removing powered loads on the diagnostic connector can have a short term stability impact.


GPSDO<->232

2 layer board of 1.25 x 1.40 inches (31.8 x 35.6 mm).
Shared on December 24th, 2017 05:32

This board adapts the GPSDO diagnostic port to RS-232. 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 SOIC-16 chip is a MAX232. The SOT23-5 is a single inverter. All 6 caps are 0.1 µF. The edge-mounted DB9 should be a female. It can connect directly to a DB9M style serial port or cable. The diagnostic connector is a CUI MD60S. You use a straight-through mini-DIN-6 cable (like a PS/2 cable) to connect up to the GPSDO.

For maximum stability, you should keep this board connected permanently if you’re going to use it. Adding and removing powered loads on the diagnostic connector can have a short term stability impact.



GPSDO<->USB

2 layer board of 1.25 x 1.00 inches (31.8 x 25.4 mm).
Shared on December 24th, 2017 05:31

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


GPSDO<->USB

2 layer board of 1.25 x 1.00 inches (31.8 x 25.4 mm).
Shared on December 24th, 2017 05:31

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



GPSDO-USB

2 layer board of 1.25 x 1.00 inches (31.8 x 25.4 mm).
Shared on November 29th, 2017 21:55

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

Use this one.


GPSDO-USB

2 layer board of 1.25 x 1.00 inches (31.8 x 25.4 mm).
Shared on November 29th, 2017 21:55

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

Use this one.



GPSDO-232

2 layer board of 1.25 x 1.40 inches (31.8 x 35.6 mm).
Shared on November 28th, 2017 17:49

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

Use this one.


GPSDO-232

2 layer board of 1.25 x 1.40 inches (31.8 x 35.6 mm).
Shared on November 28th, 2017 17:49

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

Use this one.