README.md: formatting updates to make it nicer + typo fixes.

[contrib/mraa.git] / docs / galileorevh.md

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 Galileo Gen 2 - Rev H                           {#galileorevh}
 =====================
 
-Galileo is a microcontroller board based on the Intel® Quark SoC X1000
+Galileo is a microcontroller board based on the Intel(R) Quark(TM) SoC X1000
 Application Processor, a 32-bit Intel Pentium-class system on a chip.
 
 The Gen 2 board has the following limitations in libmraa:
 
-- i2c is set at 400Khz speed cannot be changed without reloading kernel module
-- i2c bus is shared with multiple devices, scanning it usually fails
+- i2c is set at 400Khz speed cannot be changed without reloading kernel module,
+  the driver is intel_qrk_gip_i2c and the parameter is i2c_std_mode which must
+  be set to 1 in order to set the i2c bus speed to 100Khz
+- i2c bus is shared with multiple devices in kernel space, scanning it usually
+  fails
 - pwm period is set globally for all pwm channels, when changed this will halt
   all pwm channels
 - adc kernel module will return 12bit number but the ADC itself only has an
   accuracy of 10bits.
+- AIO pins are treated as 0-5 in mraa_aio_init() but as 14-19 for everything
+  else. Therefore use mraa_gpio_init(14) to use A0 as a Gpio
+
+Uart 1 on gen2
+--------------
+
+Uart 1 is connected to the FTDI header and the linux console. It's also
+possible to use it from A2(Rx)/A3(Tx). However mraa does not support this
+directly so you need to enable the muxing manually. Here is an example of how
+this is done, this was tested using an FTDI 3.3V TTL cable:
+
+$ systemctl stop serial-getty@ttyS1.service
+
+$ python
+>>> # Configure the Muxes for Uart1 on Aio2/3
+>>> import mraa as m
+>>> p77 = m.Gpio(77, False, True)
+>>> p76 = m.Gpio(76, False, True)
+>>> p16 = m.Gpio(16, False, True)
+>>> p17 = m.Gpio(17, False, True)
+>>> p77.write(1)
+>>> p76.write(1)
+>>> p16.dir(m.DIR_OUT)
+>>> p16.write(0)
+>>> p17.dir(m.DIR_OUT)
+>>> p17.write(1)
+
+>>> # For Rx to work correctly switch the level shifter
+>>> p34 = m.Gpio(34, False, True)
+>>> p34.dir(m.DIR_OUT)
+>>> p34.write(1)
+
+>>> # Use the uart
+>>> x = m.Uart(1)
+>>> x.setBaudRate(115200)
+>>> x.writeStr('hello')
+>>> x.read(5)
+bytearray(b'dsds\n')
+