IR Receive don't work on Fruit Jam

[b-blake]

CircuitPython version and board name

Adafruit CircuitPython 10.0.0-beta.2 on 2025-07-30; Adafruit Fruit Jam with rp2350b
Board ID:adafruit_fruit_jam
UID:5A5DC2FB5BCDD764

Code/REPL

# SPDX-FileCopyrightText: Copyright (c) 2024 ladyada for Adafruit Industries
#
# SPDX-License-Identifier: MIT

import board
import pulseio
import adafruit_irremote

# IR receiver setup
ir_receiver = pulseio.PulseIn(board.IR, maxlen=120, idle_state=True)
decoder = adafruit_irremote.GenericDecode()

def decode_ir_signals(p):
    codes = decoder.decode_bits(p)
    return codes
print("Setup OK.")
while True:
    print("Looking for IR pulses.")
    pulses = decoder.read_pulses(ir_receiver)
    try:
        # Attempt to decode the received pulses
        received_code = decode_ir_signals(pulses)
        if received_code:
            hex_code = ''.join(["%02X" % x for x in received_code])
        print(f"Received: {hex_code}")
    except adafruit_irremote.IRNECRepeatException:  # Signal was repeated, ignore
        pass
    except adafruit_irremote.IRDecodeException:  # Failed to decode signal
        print("Error decoding")

Behavior

IR transmitter pointed at Fruit Jam receiver at a distance of 4 inches.
Circuit Python code above does not detect any data received.
The board LED flickers when the IR transmitter buttons are pushed.

Description

No error is issued
Red board.LED flashes
No output from Circuit Python

Additional information

No response

[samblenny]

I was able to reproduce this on one of the new Fruit Jam rev D production boards with 10.0.0-beta.2 using simpler code:

import board
import pulseio
pulses = pulseio.PulseIn(board.IR, maxlen=200, idle_state=True)
print("Listening for pulses...")
while True:
    if len(pulses) > 0:
        print(pulses.popleft())

When I press buttons on an IR remote, I see the red LED blink, but no pulses are detected.

To convince yourself that the code should work, try this variation (board.BUTTON1 instead of board.IR), then press the Fruit Jam's Button 1:

import board
import pulseio
pulses = pulseio.PulseIn(board.BUTTON1, maxlen=200, idle_state=True)
print("Listening for pulses...")
while True:
    if len(pulses) > 0:
        print(pulses.popleft())

Is it possible this could be related to the RP2350 E9 erratum?

[b-blake]

FYI: I tried the following code. Only saw True on REPL.

The IRM-H6XXT has a 43.2k ohm internal pull-up resistor connected to the open collector output transistor.

`import time
import board
import digitalio

ir = digitalio.DigitalInOut(board.IR)
ir.switch_to_input(pull=digitalio.Pull.UP)

while True:
print(ir.value, end='')
time.sleep(0.001)`

[samblenny]

Looking at the schematic from https://github.com/adafruit/Adafruit-Fruit-Jam-PCB, I'm wondering if this is an E9 erratum thing since the output of the IRM-H6XXT receiver module appears to be routed through a 10K resistor. I'm far from an expert on such things, but by my reading of Dan's description at raspberrypi/pico-feedback#401, it sounds like maybe this would meet the right conditions? I could be totally wrong about that.

[b-blake]

@samblenny,

Thank you for pointing out R32 - 10k ohm. In reading the documentation for the IR Receiver the 10k resistor should be going from the output of the receiver to 3.3 volts not the GPIO pin and the Red LED. There is a good chance the IR Receiver will work if R32 is replaced by a Zero ohm resistor. As it is, the output of the IR Receiver is fighting with the 2.2k resistor and Red LED to get to the GPIO pin. The GPIO pin will always see a high, which it does. 12.2k to ground lights the LED but very dim.

If R32 is replaced with a Zero ohm resistor I think that when in IR mode the LED would be Off and then flash showing that information is being received by the IR receiver. Not a bad mode of operation and will assist in fault isolation. As it is right now the LED does flash, but VERY dimly. I contend this proves my analysis.

I now need to find R32 and place a temporary short on it to see if I am correct. There should be no danger to the receiver or the MCU. The LED/2.2k load would be less than 1 milliampere. (3.3 volts - 1.65LED volts = 1.65 volts/2.2k = 0.75 milliampere).

@ladyada et.al. Where is R32 on the Fruit Jam board?

[samblenny]

The design files are available at https://github.com/adafruit/Adafruit-Fruit-Jam-PCB

To view the board and schematic, I've been using the .sch and .brd files with Altium Viewer.

[b-blake]

@samblenny,

Thanks, that is what I did.

[dhalbert]

@ladyada for interest

[b-blake]

If R32 is replaced with a Zero ohm resistor there may be a need to ensure that the GPIO pin does not source 3.3 volts.
If it does the GPIO port may try to source power into the IR Receiver output transistor, if the IR receiver received a valid 38kHz IR signal.

A 150 ohm resistor may be a viable option. But that is why we have EEs.

Thanks @dhalbert

[ladyada]

ill tweak the value on the next batch. no need to remind me :)

[b-blake]

@ladyada,

How will those of us with the current revision find out what the tweak is?
Will there be an avenue for us to take advantage of the tweak?

The options for a HAT that plugs into the 2x16 header are enticing.

[ladyada]

it would require soldering on the board. basically any one that is sold after today will have the fix added. if you bought one before you can hand-fix or just plug in an IR receiver into the IDC blocks. if you are unable to solder we can replace it (but we have very limited stock)