Debugging of Serial port module on MTK6572 android4.4

Years ago debugging a bit with MTK Uart1 port to external modules, expand to 2 COM ports. Writing this article is mainly to tidy up the idea.

The model of expansion IC is WK2114:

WK2114 schematic diagram

It is possible to see the main interface test OK first.

mtk6572 Uart1 By default is used for log use, so to modify the permissions

chmod 0660/dev/ttymt0
Chown System System/dev/ttymt0

After the modification can be used on the phone to install a COM port apk connection computer test to see if it is normal. In general this step is no problem.

It is also possible to run into an unstable situation, which is to turn off the log function of the default uart1.

This two-step completion to ensure that the main interface function properly, and then add wk2114 driver code for debugging, the original is to be in the Samsung above the driver, on the MTK also make simple changes.

First look at the WK2114 pin description before modifying:

See above the figure gives a person's feeling is too simple, only need to modify reset and Eint on the line, the other a few quantity is OK, really is this. But it is now blocked by several problems:

1, voltage due to mtk6572 can not meet the requirements of VCC, so there is an external liter IC, flying line that call a mess. The amount can also meet the requirements, but there is no hidden danger I am not good to say.

2, tools, no oscilloscope.

3, test method.

The problem that needs to be addressed now is this:

I see the following in the source code of WK2114.C:

static struct Uart_driver Wk2xxx_uart_driver = {

Owner:this_module,
Major Serial_wk2xxx_major,
#ifdef CONFIG_DEVFS_FS
Driver_name: "Ttyswk",
Dev_name: "Ttyswk",
#else
Driver_name: "Ttyswk",
Dev_name: "Ttyswk",
#endif
Minor:minor_start,
Nr:nr_ports,
Cons:null//wk2xxx_console,
};

Later looking for information, CONS:NULL representatives can not use the console to test as before. I wonder if I understand the mistake here? Ken asked the Masters to advise them.

There is also a problem: If the expansion module is not connected to the terminal equipment, can not see the full log.

In short, there is no good debugging method at the moment.

Debugging of Serial port module on MTK6572 android4.4