kea8 pin configuration

[timbarry]

I've probably missed something obvious, but I'm struggling to get my head round the pin configurations for the KEA8. With other processors, like the KL25, every pin has a port pin control register which has a MUX field (e.g. 0 for GPIO, 1 for UART etc). In the KEA8 manual, it has a table of alternative functions, but there doesn't appear to be a MUX field for each individual pin. The SIM_PINSEL register seems to allow for a UART and I2C to connect to the same pin at the same time (i.e. by setting UART0PS to 1 and leaving I2C0PS cleared), but surely this can't be right? The table on page 134 of the reference manual also says that the majority of the pins default to analog inputs, but analog functions aren't even listed in the SIM_PINSEL register, and neither are GPIO. So how, for example, can I set PTA6 to be GPIO?

[mjbcswitzerland · Accepted solution]

Tim

The PIN muxing on the KE (and KEA) parts is based on peripheral priorities and not by specific control.

If there are no peripherals enabled that use a certain pin that pin will be GPIO.

Once a peripheral using the pin in enabled it then takes over the pin's function (without the user specifically controlling a MUX register).

If two or more peripherals are enabled that use a certain pin the peripheral with the highest priotity assumes the function, whereby the priority is simply the value in the table (with GPIO as lowest).

The SIM_PINSEL is used to define an alternative connection of particular peripherals when they are enabled.

What counts as being 'enabled' is generally defined in the peripheral's description but is something like "Tx pin connected when the Tx is enabled" etc.

Regards

Mark

Kinetis: µTasker Kinetis support

KEA: µTasker TRK-KEA8 support  / µTasker TRK-KEA64 support  / µTasker TRK-KEA128 support

For the complete "out-of-the-box" Kinetis experience and faster time to market

[timbarry]

Great, all clear now. Thanks Mark