TE0701/TE0720: Power on J21&J17 setting

[GlennW]

With TE0701 J21 and J17 jumpers both in 1-2 position (therefore connecting bank34, 33 & 13 to 3.3V), the power up of the system is not reliable.
All LEDs rapidly flash, suggesting POR is rapidly changing state.
The system can be made to start normally by pressing switch S2.

All other combinations of J21 and J17 settings appear not to show this problem.

The bench PSU being used has a current limit greater than 4Amps, so this is not the problem.

Do you observe the same?
Any suggested fix?

[Antti Lukats]

Hi

we are checking the possible causes, in our lab tests there are no problems with the jumper setting as described.

Q1: do you have anything connected to FMC or PMOD slots?
Q2: if you remove jumper J21 completly what happens?

Jumper J17 must be installed, or module would not boot (VCCIO34 is monitored)

In current CPLD design pressing S2 forces EN1 input low, and powers down everything on the modules, including 3.3V output.

Tests:

J17, J21 both in 1-2, fmc and pmod slots empty, bootable SD card inserted

powerup, then voltage from lab supply down to 5.0V module is working, press S2 > 2 leds on module, TE0701 power on led and 3 red leds blinking.
voltage up to at 5.9V module live again.

[GlennW]

My test setup is the same as yours ("J17, J21 both in 1-2, fmc and pmod slots empty, bootable SD card inserted")

Q1 answer: Nothing connected to any IO.
Q2 answer: Removing J21 prevents the fault occurring (suggesting either total load or something associated with bank 13 may be the issue?)

When the fault occurs the TE0701 "3V3IN" rail oscillates at a frequency of approx 30Hz (as per attached image).
All LEDs (except LED1, which is off) show this fast oscillating too.

[Antti Lukats]

My test setup is the same as yours ("J17, J21 both in 1-2, fmc and pmod slots empty, bootable SD card inserted")

Q1 answer: Nothing connected to any IO.
Q2 answer: Removing J21 prevents the fault occurring (suggesting either total load or something associated with bank 13 may be the issue?)

When the fault occurs the TE0701 "3V3IN" rail oscillates at a frequency of approx 30Hz (as per attached image).
All LEDs (except LED1, which is off) show this fast oscillating too.

Hi,

the 30Hz flicker happens here also, but only at input voltages below 5.5V, not otherwise.
How do you connect power ? plugging the connector into TE0701 or is it connected first?
We have seen some issues with Enpirion DCDC but none that would cause the behaviour you describe.

J21 when inserted with connect 3.3V_out to about 250 uF more capacitance ! (most of that is located on the module!)

However if you use good supply, and thick enough cable there should be no issues.

br
Antti

[GlennW]

Power is direct from bench PSU, power connector already fitted into TE0701 at power on. The wires are thick and short, there is only a few hundred milliamps current so this is unlikely a problem.

The problem you see at low voltages is a bit different I think, I can see this also.
Try running from 13V, it shows the problem quite reliably on my system.
The fault characteristics may change with different power supplies, I'll test with others.

[Antti Lukats]

Power is direct from bench PSU, power connector already fitted into TE0701 at power on. The wires are thick and short, there is only a few hundred milliamps current so this is unlikely a problem.

The problem you see at low voltages is a bit different I think, I can see this also.
Try running from 13V, it shows the problem quite reliably on my system.
The fault characteristics may change with different power supplies, I'll test with others.

1) please do not experiment with input voltages over 12V! The DCDC are rated to 14 with ABS MAX 15, but 12V should be maximum for normal use.

2) I tried with 13V here also, no anomalies

https://wiki.trenz-electronic.de/display/4X5B/CPLD+Update

Please send short email to our support email, I can send jedec for TE0701-02 that has power on DCDC enable delay added (that is same effect as holding S2 low for 500ms on poweron).

Currently I really can not repeat the issue here, not matter what combination I try (unless vin < 5.5V)

br
Antti