RP2040 - SPI failure after soft Reboot - with displayio -- every other time #4642

jerryneedell · 2021-04-20T18:45:53Z

this issue was initially opened against the STMPE610 library adafruit/Adafruit_CircuitPython_STMPE610#16
but subsequent testing has shown that it is not related to that specific library.

I was able to reproduce the same behavior with another SPI device (FRAM breakout)

First -- here is a recap of the initial issue followed by more recent findings taht hopefully help narrow down the root cause.

Issue recap:
on a feather rp2040 connected to a 2.4inch TFT featherwing (ILI9341 display) the following code has been my test program:
All code run on up to date version of CP from the latest tip of main and updated libraries

loaded as code.py


import board
import time
import digitalio
import displayio
from adafruit_stmpe610 import Adafruit_STMPE610_SPI
from adafruit_ili9341 import ILI9341

displayio.release_displays()
spi = board.SPI()
cs = board.D9
dc = board.D10
sd_cs = board.D5
ts_cs = digitalio.DigitalInOut(board.D6)
st = Adafruit_STMPE610_SPI(spi, ts_cs)

_display_bus = displayio.FourWire(spi, command=dc, chip_select=cs)

display = ILI9341(_display_bus, width=320, height=240)

print("Go Ahead - Touch the Screen - Make My Day!")



while True:
    if not st.buffer_empty:
        print(st.read_data())

On initial power-on or hard reset the code runs normally. If the code is stopped via a Control-C at the REPL then a soft reboot (Control-D) is issued, the code will fail to properly detect the SPI device (STMPE610)

code.py output:
Go Ahead - Touch the Screen - Make My Day!
Traceback (most recent call last):
  File "code.py", line 26, in <module>
  File "adafruit_stmpe610.py", line 213, in buffer_empty
  File "adafruit_stmpe610.py", line 164, in _read_byte
  File "adafruit_stmpe610.py", line 297, in _read_register
  File "adafruit_stmpe610.py", line 293, in _read_register
KeyboardInterrupt: 

Code done running.

Press an output:
Traceback (most recent call last):
  File "code.py", line 14, in <module>
  File "adafruit_stmpe610.py", line 283, in __init__
RuntimeError: Failed to find STMPE610! Chip Version 0x804

If another contol-D is issued, it will run normally and continue to alternate running and failing with each control-D issued...

I also found that if after the Control-C, I execute

import displayio
displayio.release_displays()

it will run normally on the next control-D

Also note that - if displayio is not initialized on the board, then the issue does not occur.
It only happens if the display is in use.

As noted above, I substituted an SPI FRAM breakout for the STMPE610 in the code above and reproduced the same issue.
This seems to exonerate the STMPE610 library (which does have it's quirks) and points to some other issue with CircuitPython.

I also verified that the issue does not occur with a feather_m4_express or feather_stm31f405 - it appears to be unique to the rp2040.
I also verified that the issue does occur with the feather_rp2040 and keyboard_featherewing.

Latest findings:
I have also found that the issue only occurs if a "control-c" is used to break out of the "while True" loop.
If it replace the "while True" with "for x in ramge(10000)"

import board
import time
import digitalio
import displayio
from adafruit_stmpe610 import Adafruit_STMPE610_SPI
from adafruit_ili9341 import ILI9341

displayio.release_displays()
spi = board.SPI()
cs = board.D9
dc = board.D10
sd_cs = board.D5
ts_cs = digitalio.DigitalInOut(board.D6)
st = Adafruit_STMPE610_SPI(spi, ts_cs)

_display_bus = displayio.FourWire(spi, command=dc, chip_select=cs)

display = ILI9341(_display_bus, width=320, height=240)

print("Go Ahead - Touch the Screen - Make My Day!")



#while True:
for x in range(10000):
    if not st.buffer_empty:
        print(st.read_data())

f the code runs is allowed to run until completion it will restart normally with a Control-D at the REPL.
However, if I interrupt the execution with a Control-C, then it fails as above on the next Control-D and alternates with subsequent Control-Ds as above. If allowed to complete, it always restarts on a Control-D
So, the issue appears to be related to how the system is left after a control-C interrupts the executing code.py.

I have looked at the SPI transaction with a logic analyzer but have yet to find a "smoking gun". I'll be doing more and will update with any findings.

The text was updated successfully, but these errors were encountered:

dgriswo · 2021-04-23T22:06:36Z

I've encountered this bug after building the touch deck from John Park's tutorial: https://learn.adafruit.com/touch-deck-diy-tft-customized-control-pad. Power cycling is my workaround.

Adafruit CircuitPython 6.2.0 on 2021-04-0 8000 5; Adafruit Feather RP2040 with rp2040

Traceback (most recent call last):
File "code.py", line 34, in
File "adafruit_featherwing/tft_featherwing_35.py", line 34, in init
File "adafruit_featherwing/tft_featherwing.py", line 67, in init
File "adafruit_stmpe610.py", line 281, in init
RuntimeError: Failed to find STMPE610! Chip Version 0x408. If you are using the breakout, verify you are in SPI mode.

rsbohn12 · 2021-05-25T13:45:19Z

The power cycling is a real buzzkill.

I've got the TFTFeatherWing35 and a Feather RP2040, running Adafruit CircuitPython 7.0.0-alpha.2-646-g7df5d74d9 on 2021-05-22; Adafruit Feather RP2040 with rp2040.

HX8357 drives the 3.5" TFT display
SMTPE610 touchscreen

Anything that interrupts the busy loop (filesystem update or Ctrl-C) can trigger the failure state.

RamblingGeekUK · 2021-08-02T11:33:30Z

I've encountered this bug after building the touch deck from John Park's tutorial: https://learn.adafruit.com/touch-deck-diy-tft-customized-control-pad. Power cycling is my workaround.

Adafruit CircuitPython 6.2.0 on 2021-04-05; Adafruit Feather RP2040 with rp2040

Traceback (most recent call last):
File "code.py", line 34, in
File "adafruit_featherwing/tft_featherwing_35.py", line 34, in init
File "adafruit_featherwing/tft_featherwing.py", line 67, in init
File "adafruit_stmpe610.py", line 281, in init
RuntimeError: Failed to find STMPE610! Chip Version 0x408. If you are using the breakout, verify you are in SPI mode.

I have just built and I'm seeing this also.

dhalbert · 2021-08-02T13:04:22Z

Could you all try 7.0.0-alpha.5 with this bug? I removed the ability to interrupt an SPI transaction with ctrl-C in #4974, which should be in alpha.5.

dgriswo · 2021-08-02T14:11:10Z

Adafruit CircuitPython 7.0.0-alpha.5 on 2021-07-21; Adafruit Feather RP2040 with rp2040 + Adafruit TFT FeatherWing - 3.5" 480x320 Touchscreen for Feathers PRODUCT ID: 3651

I can now enter the REPL and reload without encountering the STMPE610 error. I can also trigger a reload via filesystem write without error. The display correctly initializes in both cases.

dhalbert · 2021-08-02T14:14:11Z

OK, I will close this as fixed by #4974 for now. Please reopen if you still have trouble with alpha.5 or later. Thanks @dgriswo for quick testing!

RamblingGeekUK · 2021-08-02T14:15:18Z

I can Confirm. @dhalbert beat me to it by about 3 mins 🤣

jerryneedell added the bug label Apr 20, 2021

jerryneedell changed the title ~~RP2040 - SPI failure after soft Reboot -- every other time~~ RP2040 - SPI failure after soft Reboot - with displayio -- every other time Apr 20, 2021

tannewt added the rp2040 Raspberry Pi RP2040 label Apr 21, 2021

tannewt modified the milestones: 7.0.0, Long term Apr 21, 2021

dhalbert modified the milestones: Long term, 7.0.0 Aug 2, 2021

dhalbert closed this as completed Aug 2, 2021

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RP2040 - SPI failure after soft Reboot - with displayio -- every other time #4642

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RP2040 - SPI failure after soft Reboot - with displayio -- every other time #4642

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