You need to enable the following configuration BT_UART as this enables UART3 on FRDM-K64F (this is initially designed for Arduino BT shields such as FRDM-KW41Z).
By “cdc_acm <---> UART_3” I assume you want to forward AT commands computer->board->bt.
Once you have UART3 enabled you can continue with the same sample project forwarding commands from one terminal to UART3.
I suggest you also have a look at this help page:
We use a KW41Z as a BT Arduino shield similar to how you want to use HC05, but using UART HCI, not AT commands.
There is also subsys\bluetooth\host\at.c on what’s implemented on Zephyr’s BT subsystem with AT commands, please have a look at that.
From: users@... <users@...> On Behalf Of gnfranco via Lists.Zephyrproject.Org
Sent: Monday, July 1, 2019 6:38 PM
Subject: [EXT] [Zephyr-users] UART serial and CDC-ACM on Zephyr #bt #bt #hc5
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I would like to use Zephyr with my Frdm K64f to program an HC-05 Bluetooth module using AT commands. Could you help explaining were I need to start?
For now my board are running cdc_acm composite example and it works fine, with two serial comm terminals it's send data each one. I'd like to change this example to use one cdc_acm and UART_3. cdc_acm