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interfaces:amba [2014/12/23 07:54]
darron 		interfaces:amba [2022/07/29 01:23] (current)
darron [Resources]
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-==== ARM Amba ====+==== ARM Amba UART ====
 <wrap right> <wrap right>
 {{:interfaces:amba.jpg?200}} {{:interfaces:amba.jpg?200}}
 </wrap> </wrap>
  
-ARM Amba UARTs are found on ARM systems such as the Raspberry Pi.+These UARTs are found on systems such as the Raspberry Pi.
  
-== Files at ARM == +=== RPi ===
-[[http://infocenter.arm.com/help/topic/com.arm.doc.ddi0183f/DDI0183.pdf|Manual]]+
  
-== Files at RPi == +The following guide is very old now and has mostly become obsolete.
-[[http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf|Peripherals]]+
  
-==== RPi ====+By default, the UART is used as the Linux console, this must be disabled to allow general purpose operation.
  
-High speed modes of operation are not enabled by default and must be enabled in /boot.+The following script run as root can solve this. 
 +<code> 
 +#!/bin/sh 
 +C=`awk '{ for (i = 1; i <= NF; ++i) { if ($i !~ /ttyAMA0/) { printf $i" " } } printf "\n" }' /boot/cmdline.txt` 
 +echo $C > /boot/cmdline.txt 
 +sed -i 's/^T0:23:respawn:/#T0:23:respawn:/' /etc/inittab 
 +</code>
  
-== /boot/config.txt ==+High speed modes of operation are also not enabled by default and these should be enabled.
 <code> <code>
-init_uart_clock=64000000+echo "init_uart_clock=64000000" >> /boot/config.txt
 </code> </code>
 +
 +Reboot the RPi to apply all the settings.
 +
 +===RPi 3===
 +
 +The RPi 3 uses the UART for comms with the the built-in bluetooth module and presents a simple "mini-uart" on the regular pins.
 +
 +To swap the ports around to gain access to the faster port, do the following in config.txt
 +
 +<code>
 +dtoverlay=pi3-miniuart-bt
 +</code>
 +=== Resources ===
 +
 +[[http://infocenter.arm.com/help/topic/com.arm.doc.ddi0183f/DDI0183.pdf|Manual]]
 +
 +[[http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf|Peripherals]]
 +
 +