TMS320F28379D: CLB eCAP Peripheral Signal Multiplexer Question

Hi Ed,

Please take a look at C2000ware example ecap_capture_pwm_xbar

C:/ti/c2000/C2000Ware_3_03_00_00/device_support/f2837xd/examples/cpu1/ecap_capture_pwm_xbar

Refer to F2837xD_ECap.c

Hi Santosh,

The file you suggested shows how to use an eCAP to measure a PWM signal.

But I am trying to determine what eCAP functionality I will lose if I use the Peripheral Signal Multiplexer to output CLB signals in place of ECAPOUT and ECAPOUT_EN as identified in Table 26-3. I believe I understand ECAPOUT (please correct me if my statement in the first paragraph of my initial post is incorrect).

But I can’t find any information in the TRM as to what ECAPOUT_EN is. So I don’t know what I will be losing if I output CLB1_OUT7_1 (see Table 26-3 Peripheral Signal Multiplexer Table).

Thank you,

Ed

Ed,

I have just assigned the thread to CLB expert to help us. Due to US holidays, most of the folks are out of office so response will be delayed. Sincere apology for inconvenience.

Ed,

To drive the ECAPOUT from CLB I believe you need a 1 connected to ECAPOUT in the CLB.

I will let Bharathi comment on the ECAPOUT_EN signal.

Subrahmanya 

Nima

Hi Nima,

In order to plan the pinouts of future products, I am putting together a matrix of CLBx_OUTy_z vs which GPIO pins they are tied to, if any, and the functionality which would be muxed away if we were to use them.  In this case, I can see ECAPxOUT in Figure 16-2 and in Figure 9-5 which  shows that it can be output via the Output X-BAR which echoes the text in the TRM.

But the only reference I can find for ECAPOUT_EN is in Table 26-3 Peripheral Signal Multiplexer Table.  I haven't be able to find anything similar in the eCAP section of the TRM..  So I'm trying to figure out what the functionality of ECAPOUT_EN is, and whether or not it can be output to a GPIO.

Thank you,

Ed

Nirav Ginwala do you know what the ECAPOUT_EN signal is that the CLB can overwrite?

Nima

Nima,

Yes, Table 26-3. Peripheral Signal Multiplexer Table of TRM has this info.
CLB1_OUT6_1, CLB1_OUT7_1 correspond to ECAPOUT, ECAPOUT_EN

Subrahmanya yes but inside the ECAP module, what does the ECAPOUT_EN signal do? We dont see it in the ECAP chapter of the TRM at all.

Nima

Thank you both for looking into this. I think I am starting to understand. Please correct me if I’m wrong.

1. ECAPOUT_EN does not go to a GPIO.
2. ECAPOUT_EN is used to gate the ECAPx_OUT signal.

Item 2 does not quite make sense to me because, according to the TRM, the ECAPx_OUT signals only go to X-BARs and the CLB where they can be individually selected. In those circumstances, enables are not needed. Are the ECAPx_OUT signals used in another area where an output enable would be required? Or am I barking up the wrong tree?

Thank you,

Ed

I get it now.  The ECAPOUT_EN signal is an on/off switch not a control for a tri-state buffer.

Thanks for your help Nima,

Ed