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CD, CTS, RTS as GPIOs in MPC8321's UCC

Question asked by Subash Rajaram on Feb 16, 2017
Latest reply on Feb 28, 2017 by alexander.yakovlev

Hi Folks,


In our project we are using QUICC Engine's UCC of MPC8321 in HDLC as well as Transparent mode. The Control Signals CTS, RTS and CD should be shorted if we use the UCC in Loop-back mode or else those signals should be driven according to the third party device. 


Now the requirement is we need to configure the CTS, CD and RTS as GPIOs.

1) We tried to configure the PINS as GPIOs. But the system gets hung.

For Example, I am using UCC2 . Following are the pins and their corresponding CPPAR and CPDIR values.

PINS: PA26, PA28 and PA30

CPPAR_REGS: 00, 00 and 00

CPDIR_REGS: 11, 11 and 11


My Queries are

1) Are the Pin Configurations right to make the pins as GPIOs? 

2) What should be the CPDIR value for the respective pins?

2) Functionality wise What happens if we configure those pins as GPIO? How the Flow control will be handled?


Thanks for you Kind reply in advance.