input pin left open

[ryanshort]

I inadvertently left two input pins left open on the MPC8378:  TSEC1_COL and TSEC2_COL.  The TSEC1/2 interfaces are configured for RMII operation so these signals are not used, however per Freescale AN3665, they should have been pulled high.  The pins are not tied to traces at all so rework is not an option.  I am not experiencing any obvious functional issues, but I need to analyze what the potential effect of this design error is.  The only thing I can think of is extra power drain due to either the input oscillating, or significant cross over current flowing.  Can you please provide further insight regarding the effect of leaving an input open, and if the effect is increased power, how I might determine how much more power will be used? 

[r8070z]

The manual says that COL signal is tested only in the MII configuration. This signal is not used in the RMII. Hence we can expect only extra power drain due to float inputs.

I think you can set the SICRH[TSEC1_A]= SICRH[TSEC2_A]=1; i.e. configure TSEC1_COL, TSEC1_RX_ER as GPIO2[20, 25] and TSEC2_COL, TSEC2_RX_ER, TSEC2_TX_ER as GPIO1[21, 25,24] . And then set the float pins as general purpose output. There is mysterious RX_ER input. The RMII specs says that “RX_ER is a required output of the PHY. The switch ASIC may choose to use this input”. I have seen questions for that “RMII TSEC_RX_ER input” for PQ2 Pro and PQ3 TSECs. The answer is that TSEC chooses ignore this signal in the RMII mode.