mraa  1.5.1
Low Level Skeleton Library for Communication on GNU/Linux platforms
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UP Board

UP Board is based on the Intel(R) Atom(TM) x5-Z8350 SoC (formerly Cherry Trail). It includes 1/2/4GB RAM, 16/32/64GB eMMC flash, 6 USB2.0 ports, 1 USB 3.0 OTG port, 1 Gigabit Ethernet, HDMI and DSI/eDP Graphics ports, RTC and a 40-pin I/O header. The form-factor for the board is based on the Raspberry Pi 2, and can be used with many of the add-on HAT boards designed for the Raspberry Pi.

Interface notes

PWM PWM frequency range is from 293 Hz to 6.4 MHz. 8-bit resolution is supported for duty-cycle adjustments, but this reduces for frequencies > 97.6kHz

I2C 2 I2C channels support standard-mode (100kHz) and fast-mode (400kHz). Bus frequency can be selected in BIOS settings. Note that, unlike Raspberry Pi, the I2C controller issues Repeated-START commands for combined transactions (e.g. a write-then-read transaction) which may not be supported by some I2C slave devices. For such devices, it is advisable to use separate write and read transactions to ensure that Repeated-STARTs are not issued.

SPI Bus frequencies up to 25MHz are supported, in steps which are less granular at higher speeds. E.g. Available speeds include: 25MHz, 12.5MHz, 8.33MHz, 6.25MHz, 5MHz, 4.167MHz, 3.571MHz, 3.125MHz, etc. Please be aware that speeds in between those steps will be rounded UP to the next nearest available speed, and capped at 25MHz. 2 chip-selects are available, one natively (SPI CS0) and one by GPIO (SPI CS1).

UART 1 high-speed UART is available, supporting baud rates between 300 and

  1. Hardware flow-control signals are available on pins 11/36 (RTS/CTS).

ADC 1 8-bit single-channel ADC (TI ADC081C021) is available on pin 7.

Please note that a kernel with UP board support is required to enable the I/O interfaces above. Refer to for more information.

Pin Mapping

The GPIO numbering in the following pin mapping is based on the Raspberry Pi model 2 and B+ numbering scheme.

Note that there is an enum to use wiringPi style numbers.

MRAA Number Physical Pin Function Sysfs GPIO Notes
1 P1-01 3V3 VCC
2 P1-02 5V VCC
3 P1-03 I2C SDA1 2 I2C1 (/dev/i2c-1)
4 P1-04 5V VCC
5 P1-05 I2C SCL1 3 I2C1 (/dev/i2c-1)
6 P1-06 GND
7 P1-07 GPIO(4) 4 ADC0 (iio:device0)
8 P1-08 UART TX1 14 UART1 (/dev/ttyS1)
9 P1-09 GND
10 P1-10 UART RX1 15 UART1 (/dev/ttyS1)
11 P1-11 GPIO(17) 17
12 P1-12 I2S CLK 18 I2S0 (PCM Audio)
13 P1-13 GPIO(27) 27
14 P1-14 GND
15 P1-15 GPIO(22) 22
16 P1-16 GPIO(23) 23
17 P1-17 3V3 VCC
18 P1-18 GPIO(24) 24
19 P1-19 SPI MOSI 10 SPI2 (/dev/spidev2.x)
20 P1-20 GND
21 P1-21 SPI MISO 9 SPI2 (/dev/spidev2.x)
22 P1-22 GPIO(25) 25
23 P1-23 SPI SCL 11 SPI2 (/dev/spidev2.x)
24 P1-24 SPI CS0 8 SPI2 (/dev/spidev2.0)
25 P1-25 GND
26 P1-26 SPI CS1 7 SPI2 (/dev/spidev2.1)
27 P1-27 I2C SDA0 0 I2C0 (/dev/i2c-0)
28 P1-28 I2C SCL0 1 I2C0 (/dev/i2c-0)
29 P1-29 GPIO(5) 5
30 P1-30 GND
31 P1-31 GPIO(6) 6
32 P1-32 PWM0 12 PWM Chip 0 Channel 0
33 P1-33 PWM1 13 PWM Chip 1 Channel 0
34 P1-34 GND
35 P1-35 I2S FRM 19 I2S0 (PCM Audio)
36 P1-36 GPIO(16) 16
37 P1-37 GPIO(26) 26
38 P1-38 I2S DIN 20 I2S0 (PCM Audio)
39 P1-39 GND
40 P1-40 I2S DOUT 21 I2S0 (PCM Audio)