Changes to be made to ZP3 Interface Dev Board:
- Change 2.54mm pin socket connectors to match Pixhawk Connector Standard (Pixhawk-Standards/DS-009 Pixhawk Connector Standard.pdf at v6xupdate · pixhawk/Pixhawk-Standards · GitHub)
- Remove ST-Link connector
- Decide on which sensors to add (if any) with EFS
- Remove LEDs?
- Add IMU
CONNECTORS
All interfaces which have a pixhawk standard connector (UART, I2C, SPI, ST-Link) except for debug (ST-Link) will be replaced with GH series JST connectors. Debug will use SH series. The rest (GPIO, ADC input, TIM) don’t have a standard, and thus will use found in COTS products or what intuitively feels convenient.
As is the case with the Pixhawk FC, only upwards-facing JST connectors will be used.
Replace ST-Link socket (J30) with BM10B-SRSS-TB connector. This is a 10-pin upwards-facing SMT connector. It is the standard “Pixhawk Debug Full” connector. There is a “mini” version with only 6 pins, but it does not seem to have an nRST pin, which is needed for ST-Link.
From the PX4 user guide, the following pin connections will be made:
#Full | Pixhawk Debug |
|---|---|
1 | VCC |
2 | x |
3 | x |
4 | SWDIO |
5 | SWCLK |
6 | SWO |
7 | x |
8 | x |
9 | nRST |
10 | GND |
Note: the connector-standard pdf document does not identify the location of the nRST pin, but the user guide specifies it as being on pin 9.
UART conn (4-pin: J6, 11, 34; 6-pin: 18, 23). Using 6-pin standard telemetry connector (BM06B-GHS-TBT). On 4-pin UART, CTS and RTS are left floating.
SPI conn (J26, 27). Replace with BM07B-GHS-TBT 7-pin connector. NSS will be connected to the SS1 pin and the SS2 pin will be left floating.
I2C conn (J7, J12, J16). Replace with BM04B-GHS-TBT 4-pin connector.
On the Pixhawk, there are BM08B-GHS-TBT 8-pin connectors which share GPIOs and ADC inputs
The following is their pinout (pin 1 VCC, pin 8 GND, pins 2-5 GPIOs, pin 6-7 ADC inputs)
There are 10 GPIOs + 3 ADC inputs on our flight board, we can use 2 8-pin connectors containing all GPIOs and 1 8-pin connector containing all ADC inputs. Another option would be to:
GPIO conn (J31, 32). Replace with 2 8-pin (or either 0.1” pitch through hole solder pads for option of using pin headers or direct soldering).
ADC conn (J28). 0.1” Pin sockets/headers.
TIM conn (J3, 4, 9, 10, 14, 15, 19, 20, 21, 22, 8, 13, 17, 24, 25, 29). Going to use a 3-row 16-pin per row 0.1” right-angle pin header. This is shown to be done by Pixhawk here.
IMU
ICM-42670-P seems like a widely available low-power option (and apparently low noise) . Need to find out the desired orientation and placement of the IMU on the board (Since it’s recommended for it to be in the center of the drone and to align expectedly with the yaw/pitch/roll axis)
