topic Flexbus on K53 with MII/RMII network in Kinetis Microcontrollers

Flexbus on K53 with MII/RMII network

kfranz — Wed, 25 May 2022 13:36:20 GMT

We need to use the flexbus on a K53 and maintain the ability to use RMII for the network interface. There seems to be a conflict with pin usage when trying to do this.

How do I use flexbus and still use the RMII interrface?

Re: Flexbus on K53 with MII/RMII network

kfranz — Wed, 25 May 2022 14:09:38 GMT

My goal is to connect an external SRAM chip. Preferably with at least 128KB of SRAM.

Re: Flexbus on K53 with MII/RMII network

kfranz — Fri, 26 Aug 2022 14:12:07 GMT

We accomplished this by not connecting the trace pins. PTA6 (TRACE_CLKOUT), PTA7 (TRACE_D3), PTA8 (TRACE_D2), PTA9 (TRACE_D1), and PTA10 (TRACE_D0) were originally connected to the Cortex-M JTAG 20-pin debugger. If you are not using the JTAG trace capability, these pins do not need to be connected to the debugger. They can then be used for the flexbus. This makes connecting an external RAM to the flexbus possible and also use the RMII interface.