• Power management feature by suspending and resuming the URT ports
• Standard TTY layer IOCTL calls
All the UART ports can be accessed from the device files /dev/ttymxc0 to /dev/ttymxc1.
Autobaud detection is not supported.
NOTE
If you want to use the DMA support for UART please also
enable the RTS/CTS for it. The DMA may be abnormal if you
do not enable the RTS/CTS.
39.2 Hardware Operation
Refer to the i.MX 6Solo/6DualLite Applications Processor Reference Manual to
determine the number of UART modules available in the device.
Each UART hardware port is capable of standard RS-232 serial communication and has
support for IrDA 1.0.
Each UART contains a 32-byte transmitter FIFO and a 32-half-word deep receiver FIFO.
Each UART also supports a variety of maskable interrupts when the data level in each
FIFO reaches a programmed threshold level and when there is a change in state in the
modem signals. Each UART can be programmed to be in DCE or DTE mode.
39.2.1 Software Operation
The Linux OS contains a core UART driver that manages many of the serial operations
that are common across UART drivers for various platforms.
The low-level UART driver is responsible for supplying information such as the UART
port information and a set of control functions to the core UART driver. These functions
are implemented as a low-level interface between the Linux OS and the UART hardware.
They cannot be called from other drivers or from a user application. The control
functions used to control the hardware are passed to the core driver through a structure
called uart_ops, and the port information is passed through a structure called uart_port.
The low level driver is also responsible for handling the various interrupts for the UART
ports, and providing console support if necessary.
Each UART can be configured to use DMA for the data transfer. These configuration
options are provided in the mxc_uart.h header file. The user can specify the size of the
DMA receive buffer. The minimum size of this buffer is 512 bytes. The size should be a
multiple of 256. The driver breaks the DMA receive buffer into smaller sub-buffers of
Hardware Operation
i.MX 6Solo/6DualLite Linux Reference Manual, Rev. L3.0.35_4.1.0, 09/2013
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Freescale Semiconductor, Inc.
