PSoC™ 5, 3 & 1 Forum Discussions

I am designing a small battery operated device that must operate without a USB connection, but at times connect to USB for both communication and battery charging.  I would like to use 2.5V for Vddd.  I am concerned about the signaling voltage levels on D+ and D-.  My research suggests that these need to have a 3V differential between them.  But how is this possible when Vddd is only 2.5V?  I don't see facility anywhere to use the 5V VBUS for *strictly* USB purposes, because D+ and D- pins are specially designed to use Vddd and not a Vddio pin.

Meanwhile, in the PSoC5 LP datasheet I find on page 73 table 11-14, cases quoting Vddd=1.8V.  This implies the task can be done with Vddd=2.5V.  But how is Vohusb in the same table produced to be between 2.8V and 3.6V?  I have seen mention of a 3.3V regulator, but if that's the solution, I would worry that it's only a step-down regulator without step-up capability from 1.8V or 2.5V up to 3.3V.

I've been searching for a while for an appnote or other advice on how to do PSoC5 LP usb communication with Vddd below 3V, such as my desired 2.5V or the previously table implied 1.8V.  But I can't find anything.

Is there advice out there somewhere?  Or can you please offer advice?  Is there a simple solution here?

It does occur to me to make Vddd automagically float up from 2.5V (battery power) to 3.3V (when USB connected), and then use a separate Vddio=2.5V pin for interfacing with my 2.5V-only peripheral.  Perhaps involve an ideal-diode chip.  But this gets a little complicated.  I'd rather not have to do that if there is a more simple solution.

Finally, I would also like for my software to know when the USB is connected.  For this purpose, I am considering using the VBUS to GPIO circuit on page 16 of the USBFS_v2_50.pdf datasheet.  I realize this uses the resistor divider to reduce 5V to 3.3V, so I would use two 30K resistors to reduce 5V to 2.5V.  Yes, I know this is simple and understand it.  I came to this point, however, by considering configuring the USBFS component to do "Enable VBUS Monitoring".  I believe that's intended for self-powered devices.  Maybe I should just use it as GPIO and be done with it,  But the whole "Enable VBUS Monitoring" and self-powered vs bus-powered question sort of bleeds over into this subject as well.

Thanks very much in advance for your help.

-Helmut

 Hi,

I have two Cisco 3650 and used StackWise-160 between switches, the all the servers connected to the first 3650 and the edge switches connected to the second 3650, the StackWise-160 use to transfer data between two 3650 switches?

 Hi everyone,

the project I'm working on contains 21 outputs multiplexed on 3 shift registers 74HC595 cascaded. I'm controlling them with a DATA pin, LATCH pin and a clock. I need to refresh these 21 outputs very fast (at 25kHz) and I don't want the CPU to be overload by it because it's already managing many tasks. I think I can use a ShiftReg component to automate the process of refreshing outputs, but I don't know how to put down the LATCH pin during the shifting time in the 74HC595. And if possible, I would like to keep it automatised in order to not occupied the CPU.
Does anyone know how I could do? or maybe did that in a project?

Thank you,

Nicolas

Being very experienced hardware guy, I have UART sending info to host computer. However I can only send ascii characters (just to verify it all works).  But I can't figure out what to do in code. Tried using sprintf to convert, etc, but so far nothing works. So, pretend I have a value, a=57, for example. How do I process that and use UART calls to send it out ?

Thank you. Bob

 Hi there

I would like to use a PSOC 3 device (48 pins or more) which has a temperature range of upto 125°C. I only see the SSOP-48 and 100-TQFP packaged supported. Are there plans for other packages (48/64-QFN) planned in the near future to support this temperature range ?

Thanks

Patrick

Hi,

Iam new to PSOC devises. Iam using an CY8C5888 witch is a very cool device. I have played around with the USBUART component and I have noticed a strage behavior. When I plug the USB in my notebook docking station or USB hub then all works fine. But if I use one of the USB ports witch are located in my notebook then the Windows 7 tells my that there is a unknown device. The Vendor PID is 0 and Iam not able to install a driver. 

Dose anyone have a idea what could be the reason? (The USBUART example from the PSOC creator studio dose have the same behavior. )

thanks a lot for your answers! 

Hi,

for a project with a CY8Y5856 with a display I need to store lots of text to be displayed.

How can I put the text into the program memory so that it does not waste RAM?

The text should be stored in a struct or at least in an array.

Best regards,

Günter

 So I have a hex file that starts with 

FF380001020304050607

has lots of hex like that and ends with FF3B0001020304050607.

I would like to know what this format is, and how to get some some meaningful output so I can modify it.