1.9 KiB
UEXT Connector (P2)
UEXT overview
the development boards so customer can choose which feature he want to use.
UEXT (Universal-Extension-Connector) is board to bard connector which support 3 serial communication interface, such as I2C, SPI, RS232. The combination of theese feature is supported by every decent microcontroller, this will enable broad choice to connect modules. UEXT gives you freedom to choose module that you want to use.
!!! Notice As UEXT have RS232 and the Rx and Tx signals should be crossed we can say that UEXT on the board is with HOST; UEXT on the module is with SLAVE/DEVICE layout.
---TBU---
Pinout Table
Helios64 provides UEXT on header P2 which following the UEXT standard, containing UEXT, SPI, and I2C connector. You can find the P2 header from the connector/interface list at hardware overview page.
Below is the detailed description of UEXT header pinout:
| PIN | Port | Remarks |
|---|---|---|
| 1 | 3.3V | |
| 2 | GND | |
| 3 | TXD (UART) | |
| 4 | RXD (UART) | |
| 5 | SCL (I2C) | |
| 6 | SDA (I2C) | |
| 7 | MISO (SPI) | |
| 8 | MOSI (SPI) | |
| 9 | SCK (SPI) | |
| 10 | SSEL (SPI) |
!!! Warning Please note the UEXT connector at Helios64 board doesn't provide the plastic covering, so be carefull with the header polarity! Make sure your device is correctly oriented before connecting!
SPI and I2C
---linked to SPI and I2C pages, TBU---
Exception
We have connected the UART bus from the RK3399K to the serial console in the USB-C, so there is no dedicated line of UART in the UEXT connector. The UART bus in this UEXT header is the parallel ones with the serial console. Therefore if you connect some module which might require dedicated serial UART line to the RK3399K, this module will not be detected.
!!! Notes Please note also, that GSM modules in UEXT format also will not work due to similar reason.