External Power on CY8CKIT-059

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
ScYa_2781401
Level 2
Level 2

I have several CY8CKIT-059 boards that I have been trying to use with external power, other than that supplied through the USB cable connected to the KitProg.  I need to use a heftier power supply than what can be supplied through the KitProg or the USB cable at the far end of the board.  It's because of the number and type of devices I have attached to the board, mainly (4x20 LCD display w/backlight, DS3231 RTC module, ENC28J60 chip for an ethernet connection, for now).  The attached devices really suck too much juice for me to run through the USB connection.

What I am running into is a problem with programming through the KitProg, while powering the board externally.  I know about removing D1 on the KitProg board to prevent power from backfeeding to the KitProg, but that introduced a new problem.  Once I remove D1, I can't program the 5LP at all, or even see it through the Bridge Control Program.  That's been also tried with a second USB cable connected to the far end of the board, which does power it up.  If I put D1 back, then it works, but with D1 out, it won't program.

I've tried running 5V power to VDD on the main board.  I've tried through the target USB connector, per section 4.2.3 of the manual.  I suppose that I could just power all of the external devices using external power, but I'm not thrilled with the idea that power might backfeed through the IO pins.

I'm open to suggestion.

Again, if D1 is removed then I can't do diddly, programming-wise.  I have NOT snapped the boards apart, mostly because I don't want to track down programming boards (I tend to lose them until I find 6 at a time, just after ordering more)

If I supply power through the target USB connector, the 5LP chip seems to get a bit warm, which also makes me nervous.  And that's with D1 removed.

Scott.

0 Likes
1 Solution
ScYa_2781401
Level 2
Level 2

I finally decided just to use the diodes as-is, mostly because for now I'm just doing this on a breadboard.  When I get to the point where I'll need just the prototyping board only I'll snap off the KitProg.  Getting power through VDD or the USB connection is working, and I'm minimizing the amount of time that the KitProg board is connected to a PC.

It would be helpful if the documentation had a bit more about using this with external power, but I understand that this is just a prototyping board, and that probably doesn't come up for a lot of people.

View solution in original post

0 Likes
6 Replies