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Rock Pi Development Column
Previous: " Rock Pi Development Notes (2): Start with Rock Pi 4B plus (based on Rising Micro RK3399) board and make the system run "
Next: Stay tuned…
foreword
In the last article, we gave an overview of the entire rock pi series. We started to evaluate the RK3399, started with the RK3399, and explained the basic peripherals.
Onboard peripherals
- USB3.0 × 2
- USB2.0 × 2
- Gigabit Ethernet port × 1
- Audio input × 1
- MIPI CSI × 1
- HDMI × 1
- MIPI DSI × 1
- 802.11 ac / wif × 1
- PoE × 1
- RTC battery port × 1
- PCIE M.2 × 1
- TF × 1
40pin general-purpose input and output pins
Introduction of GPIO 40 pin
- The function marked in orange is the default function of the pin
- All pins are routed directly to Soc RK3399 except power pins
- For pins 3, 5, 27, 28, 29, and 31, each pin is connected to a 3.0V supply through a 4.7K pull-up resistor
- Pins 19, 21, 23, 24 are routed directly to the pins of the SPI device on the board
- Pin 7 is routed directly to the MIPI CSI pin on the board
- UART asynchronous transfer protocol
UART2 is enabled by default as U-boot and Linux serial console, and the parameter is " 1500000,8,1,N " (special note: serial port use must use serial port TTL adapter board, rock pi's uart is 3.3V , there is no serial level chip, can not directly connect to the computer serial port 12V level);
UART2 & UART4 support a wide range of baud rates. It includes but is not limited to the following baud rates. For example, 115200bps. 500000bps, 1500000bps, etc.;
For v1.4 and later hardware, the onboard SPI flash is soldered, and the UART4 PIN is used for the SPI function; - For I2C-2 and I2C-7
officials have been tested with i2c device e2prom. Open the i2c device file for read and write operations.
Count the hardware resources of a single item
- GPIO pins × 27
- I2C bus × 2
- **I2S bus (audio bus)** × 1 (libmraa library not given)
- SPI bus × 2
- UART bus × 2
- PWM × 2
- ADC x 1
- 5V × 2
- 3.3V × 2
- GND × 8
Voltage characteristics of GPIO output ports
The tolerance of the IO port should be the maximum voltage or tolerance that can be tolerated (further confirmation is required).
Serial number calculation of GPIO port
GPIO port general library libmraa
Like the Raspberry Pi, it provides the libmraa library (similar to the wiringpi library of the Raspberry Pi) that can operate the underlying driver pins.
Hardware resources previously counted:
- GPIO pins × 27
- I2C bus × 2
- I2S bus (audio bus) × 1 (libmraa library not given)
- SPI bus × 2
- UART bus × 2
- PWM × 2
- ADC x 1
- 5V × 2
- 3.3V × 2
- GND × 8
compares the enable configuration of libmraa library, as shown below:
(should be 2 uarts, but 2 is the default debug port)
Previous: " Rock Pi Development Notes (2): Start with Rock Pi 4B plus (based on Rising Micro RK3399) board and make the system run "
Next: Stay tuned…
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the original article when reprinting. The blog address of this article: https://hpzwl.blog.csdn.net/article/details/123114486