P2 Eval RevB first impressions
samuell
Posts: 554
Hi,
I wanted to seize this opportunity to give you my first impressions on the RevB board. Of course, feel free to share yours, so this thread is not futile (me rambling about the board).
So, here it is what I think:
- Overall, the design is much cleaner and also safer than the previous design. A typical case where less is indeed more.
- The local jumpers for VIO selection are gone, and I'm happy with that decision. The SMD jumpers that the previous board have are a point of failure, because they can rip the pads off. Plus, the DC-DC converter was noisy, so using the local LDOs would fit applications using both analog and digital capabilities.
- The extra "ACC HDR 5V" is a neat safety feature that prevents damaged pins/banks. Many applications don't require 5V, and it is safe to just undo that jumper when probing pins.
- The DC-DC converter is significantly smaller, leaving the area tidier. Maybe as a consequence of the next, and last, point.
- Gone with the hand warmer (just kidding), as the new chip consumes roughly half the power of the previous one. The current consumption is just 22mA when idle and 90mA during multest, so well within the limit as described in the USB 2.0 specification. Haven't run primes with it (yet).
However, there is on caveat. I've sniffed the USB descriptors:
Kind regards, Samuel Lourenço
I wanted to seize this opportunity to give you my first impressions on the RevB board. Of course, feel free to share yours, so this thread is not futile (me rambling about the board).
So, here it is what I think:
- Overall, the design is much cleaner and also safer than the previous design. A typical case where less is indeed more.
- The local jumpers for VIO selection are gone, and I'm happy with that decision. The SMD jumpers that the previous board have are a point of failure, because they can rip the pads off. Plus, the DC-DC converter was noisy, so using the local LDOs would fit applications using both analog and digital capabilities.
- The extra "ACC HDR 5V" is a neat safety feature that prevents damaged pins/banks. Many applications don't require 5V, and it is safe to just undo that jumper when probing pins.
- The DC-DC converter is significantly smaller, leaving the area tidier. Maybe as a consequence of the next, and last, point.
- Gone with the hand warmer (just kidding), as the new chip consumes roughly half the power of the previous one. The current consumption is just 22mA when idle and 90mA during multest, so well within the limit as described in the USB 2.0 specification. Haven't run primes with it (yet).
However, there is on caveat. I've sniffed the USB descriptors:
Propeller P2-EVAL-ES Manufacturer: Parallax Inc. Serial Number: DN43WD9K Speed: 12Mb/s (full) Bus: 3 Address: 7 USB Version: 2.00 Device Class: 00(>ifc ) Device Subclass: 00 Device Protocol: 00 Maximum Default Endpoint Size: 8 Number of Configurations: 1 Vendor Id: 0403 Product Id: 6015 Revision Number: 10.00 Config Number: 1 Number of Interfaces: 1 Attributes: a0 MaxPower Needed: 500mA Interface Number: 0 Name: usbfs Alternate Number: 0 Class: ff(vend.) Sub Class: ff Protocol: ff Number of Endpoints: 2 Endpoint Address: 81 Direction: in Attribute: 2 Type: Bulk Max Packet Size: 64 Interval: 0ms Endpoint Address: 02 Direction: out Attribute: 2 Type: Bulk Max Packet Size: 64 Interval: 0msAs you can see, the hardware revision is set to 10.00, and this is the same version as in the RevA board. It doesn't make sense to me. It should be BCD 0100 (1.00) for the RevA and BCD 0200 (2.00) for the RevB.
Kind regards, Samuel Lourenço
Comments
But, you can probably get the config program from Parallax to change it yourself.
Remember though, some of us will be using different USB UARTS on our boards. In fact, my board will not come with it onboard.
Complicating things more is that the HW ID inside the P2 ES2 part, has bumped to 'G' from 'A', so should the USB ID reflect the 'G' somewhere ?
The version descriptor only accepts numbers in BCD form, if I'm not mistaken.
Kind regards, Samuel Lourenço
This is the USB serial chip ID only, there is no way that this chip can know what it is connected to on its serial port. However anyone including the pcb manufacturer such as Parallax can program in a new ID that may mean something. You can even change it yourself.
FT PROG
Of course the serial chip has no way of knowing about the chip it is connected to, nor it has to. The FTDI chip has to be programmed in order to reflect the hardware version of the board, and not the version of the P2, by any means. This is something I do for every product of mine, although nowadays I use CP2130 chips. But the story is the same.
For instance, here are the descriptors for a specimen of ITUSB1 Rev. 0:
And for a specimen of ITUSB1 Rev. A:
Notice the difference in revision number. My numbering scheme goes as follows:
Rev. 0 => 1.00
Rev. 1 => 1.01
Rev. 2 => 1.02
Rev. A => 2.00
Rev. A1 => 2.01
Rev. A2 => 2.02
Rev. B => 3.00
Rev. B1 => 3.01
Rev. B2 => 3.02
...and so on.
Of course Parallax could follow the numbering scheme that sees fit, but nonetheless, is good practice to reflect the hardware version on the correspondent USB descriptor, it the option is made available. If the software doesn't make that available, that is a different story (could well be the case).
Kind regards, Samuel Lourenço
Remember also these are EVALUATION boards, both rev A and B will someday be in my desk drawer collecting dust whilst I work on a production board like the FLiP2 or something. I am more interested in getting on to discovering all the possibilities of P2, and we are just opening the book right now...
Finally, How many Windoze 7 and 10 builds are out there, thousands, but they are still Win 7 / 10.
Anyway, this is a small issue.
Kind regards, Samuel Lourenço