Issue with scroll pHAT HD - [Errno 121] Remote I/O error

Support
1

Hi everyone,
I’m having some issue with the Scroll pHAT HD. Every time I used it with the raspberry pi Zero WH, after the commands:

import scrollphathd as sphd
sphd.set_pixel(1, 3, 0.5)
sphd.show()

(or after set other pixels configuration) I got the same error message:
pi@zero2:~ $ python conta_1

Press Ctrl+C to exit!

Traceback (most recent call last):
File “conta_1”, line 35, in
scrollphathd.show()
File “/usr/lib/python2.7/dist-packages/scrollphathd/is31fl3731.py”, line 550, in show
self.setup()
File “/usr/lib/python2.7/dist-packages/scrollphathd/is31fl3731.py”, line 106, in setup
self.show()
File “/usr/lib/python2.7/dist-packages/scrollphathd/is31fl3731.py”, line 590, in show
self._bank(next_frame)
File “/usr/lib/python2.7/dist-packages/scrollphathd/is31fl3731.py”, line 627, in _bank
self.i2c.write_i2c_block_data(self.address, _BANK_ADDRESS, [bank])
IOError: [Errno 121] Remote I/O error

and some “random” pixels light up (see the pic that I attached, the “random pixel configuration” on the pHAT HD is something similar)

Here’s the output of running i2cdetect -y 1

pi@zero2:~ $ i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: – -- – -- – -- – -- – -- – -- –
10: – -- – -- – -- – -- – -- – -- – -- – --
20: – -- – -- – -- – -- – -- – -- – -- – --
30: – -- – -- – -- – -- – -- – -- – -- – --
40: – -- – -- – -- – -- – -- – -- – -- – --
50: – -- – -- – -- – -- – -- – -- – -- – --
60: – -- – -- – -- – -- – -- – -- – -- – --
70: – -- – -- 74 – -- –

I tried the same raspberry pi Zero WH (with the same GPIO Hammer Header (Solderless) - Female) and another scroll phat HD and, with this configuration, everything works properly.

Since i saw in some forum that this issue could be related to the soldering of the header, i tried to connect directly the pinout of raspberry pi with the phat hd, but i got the same issue:

pic2
pic2.jpg3024×4032 2.22 MB

Some advice?

Many many thanks!!!

2

The IO error message is likely because your jumpers aren’t making a good reliable connection.
Plus, according to the GPIO pinout, https://pinout.xyz/pinout/scroll_phat_hd# it uses pin 9 for ground, not pin 6

3

Hi, thanks for your help
looking at this page https://it.pinout.xyz/pinout/scroll_phat_hd I thought it was the same to use pin 6 or 9 or 14 or…
I use now the pin 9 but I got the same error
and I got this error also using the GPIO Hammer Header (Solderless) - Female (that’s the reason why I tried to use the jumper)

4

On the Raspberry Pi all the ground pins are a common pin, they are all electrically connected to each other. Thats not always the case with Hats and pHats. They assume they will be plugged into the Pi directly, which will then link them all together on the Hat too. It can be tricky linking them all together on the Hat of Phat due to limited space etc. Plus its only a double sided board, not multi layer like the Pi’s circuit board.
Anyway I think thats one of the reasons for the GPIO pinout site.

You could very well have a defective unit. I was going by the picture, and have to admit to missing the hammer header part.

So you put a hammer header on it, then removed it?
And just to confirm, it was a “hammer” header you ordered separately and not the female header that comes with the Scroll pHat HD?

5

many thanks for your help,
yes, I used a Hammer Header (Solderless) - Female (and not the “only” female header). After having the issue, I removed it from the pHat to try with the jumpers.
here you can find the issue with the hammer header

1
pic.1.jpg3024×4032 2.32 MB

6

and here the hammer header that i used:

pic3
pic3.jpg3024×4032 1.76 MB

I can’t upload 2 pics, sorry

7

Ok, just wanted to confirm it was an actual hammer header. The normal solder in one will give you the same issue your getting with using the jumpers.
I think Unicorn pHat HD is defective. Go to the Shop Page and then look for a “Contact Us” link at the bottom. Explain the issue one more time and put a link in that e-mail to this thread and see what they say.

8

I’ll do!!
Again, many many thanks for your support!!!