54 lines
1.9 KiB
Markdown
54 lines
1.9 KiB
Markdown
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## UEXT Connector (P2)
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### UEXT overview
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the development boards so customer can choose which feature he want to use.
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UEXT (Universal-Extension-Connector) is board to bard connector which support 3 serial communication interface, such as I2C, SPI, RS232.
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The combination of theese feature is supported by every decent microcontroller, this will enable broad choice to connect modules.
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UEXT gives you freedom to choose module that you want to use.
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!!! Notice
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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.
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---TBU---
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### Pinout Table
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Helios64 provides UEXT on header P2 which following the UEXT standard, containing UEXT, SPI, and I2C connector.
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You can find the P2 header from the connector/interface list at [hardware overview](/helios64/hardware) page.
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Below is the detailed description of UEXT header pinout:
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| PIN | Port | Remarks |
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|-----|------|-------------|
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|1 |3.3V|
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|2 |GND|
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|3 |TXD (UART)|
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|4 |RXD (UART)|
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|5 |SCL (I2C)|
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|6 |SDA (I2C)|
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|7 |MISO (SPI)|
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|8 |MOSI (SPI)|
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|9 |SCK (SPI)|
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|10 |SSEL (SPI)|
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!!! Warning
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Please note the UEXT connector at Helios64 board doesn't provide the plastic covering, so be carefull with the header polarity!
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Make sure your device is correctly oriented before connecting!
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### SPI and I2C
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---linked to SPI and I2C pages, TBU---
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### Exception
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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.
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The UART bus in this UEXT header is the parallel ones with the serial console.
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Therefore if you connect some module which might ***require dedicated serial UART line*** to the RK3399K, this module ***will not be detected***.
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!!! Notes
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Please note also, that GSM modules in UEXT format also will not work due to similar reason.
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