# Problem receiving RF data on serial port

**URL:** <https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811>\
**Category:** General\
**Created:** [5 October 2023 18:39 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811 "2023-10-05T18:39:28Z")\
**Posts on this page:** 16\
**Page:** 1

<div class="post-metadata">

**Author:** ![Paul-Reed](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/paul-reed/32/66906_2.png) [@Paul-Reed](https://discourse.nodered.org/u/Paul-Reed)\
**Post date:** [5 October 2023 18:39 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/1 "2023-10-05T18:39:29Z")

</div>

I have a Raspberry Pi v3b fitted with a RF Hat, to receive data from remote sensors which I then process in node-RED -\> Influx.  
**This has worked reliably for several years** , but for some reason a few weeks ago, in the middle of the night, the data stopped arriving in node-RED.

I checked the output from the `Serial In` node which is configured for port `/dev/ttyAMA0` at a baud rate of 38400, and is the same Pi wearing the Hat, but nothing at all was output.  
I also checked minicom on the Pi - `minicom -b38400 -D/dev/ttyAMA0`, and again - nothing received.  
As I have several remote sensors, it's most unlikely that all of them stopped transmitting at the same time.

As the Pi otherwise appeared to be functioning OK, I thought that maybe the Hat had developed a fault, so I posted the Hat to a colleague (who manufactures the RF Hat's) to run a bench test, and surprise - it worked great...

So I'm assuming that it's a problem with my Pi, but no idea where to start looking. Anyone any ideas please?

---

<div class="post-metadata">

**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [5 October 2023 19:14 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/2 "2023-10-05T19:14:27Z")

</div>

I assume you've checked dmesg and other logs for any errors?

Do you know if there was a system update at that point?

Did you check that the device is still on ttyAMA0? While I don't think it would change mid-use, they can, of course, change on reboot.

---

<div class="post-metadata">

**Author:** ![Paul-Reed](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/paul-reed/32/66906_2.png) [@Paul-Reed](https://discourse.nodered.org/u/Paul-Reed)\
**Post date:** [5 October 2023 19:19 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/3 "2023-10-05T19:19:54Z")

</div>

> [@TotallyInformation](#):
>
> I assume you've checked dmesg and other logs for any errors?
> 
> Do you know if there was a system update at that point?

As the Pi runs on a SD card, all logging is disabled.  
If I can remember how I disabled them, I could restore them and have a look.

> [@TotallyInformation](#):
>
> Did you check that the device is still on ttyAMA0?

How could I check?

---

<div class="post-metadata">

**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [5 October 2023 19:37 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/4 "2023-10-05T19:37:54Z")

</div>

![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/1/d/1d3cb7643f2a53c06df1ab42d069f2020e120b32.png)

That will usually give you the clue you need. If it doesn't then we'll have to dig out the USB commands that show you the descriptors for each device.

Sorry, I meant this:

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/d/6/d61089c4f8b785c5b467bacbb9de7c44e71116cd.png)

---

<div class="post-metadata">

**Author:** ![Paul-Reed](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/paul-reed/32/66906_2.png) [@Paul-Reed](https://discourse.nodered.org/u/Paul-Reed)\
**Post date:** [5 October 2023 19:40 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/5 "2023-10-05T19:40:47Z")

</div>

Thanks Julian  
I'm still awaiting the Hat being delivered back to me, when it arrives I'll give that a try.

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [6 October 2023 07:42 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/6 "2023-10-06T07:42:34Z")

</div>

> [@Paul-Reed](#):
>
> As the Pi runs on a SD card, all logging is disabled.

That is not necessary, at least for syslog. A good quality card large enough that there is a good amount of unused space for load levelling will last for many years. When events such as you describe occur you need to be able to see the logs.

---

<div class="post-metadata">

**Author:** ![Paul-Reed](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/paul-reed/32/66906_2.png) [@Paul-Reed](https://discourse.nodered.org/u/Paul-Reed)\
**Post date:** [9 October 2023 18:27 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/7 "2023-10-09T18:27:49Z")

</div>

> [@TotallyInformation](#):
>
> Sorry, I meant this:
> 
> ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/d/6/d61089c4f8b785c5b467bacbb9de7c44e71116cd.png)

I'm getting;

```auto
pi@raspberrypi:~ $ ls -l /dev/serial/by-id
ls: cannot access '/dev/serial/by-id': No such file or directory

```

It's on a Raspberry Pi 3B running Buster, and there is no `serial` sub directory within `/dev`

Could my issue be related to this post made in the HA forum? [No /dev/serial/by-id/ entries after latest update - #2 by vitat6atlan - Hardware - Home Assistant Community](https://community.home-assistant.io/t/no-dev-serial-by-id-entries-after-latest-update/562195/2)

---

<div class="post-metadata">

**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [9 October 2023 21:30 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/8 "2023-10-09T21:30:13Z")

</div>

Well, how weird. I'm running Buster on an old laptop and I've not experienced this at all.

But even so, you should have the `/dev/serial` folder from what those threads were saying.

![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/f/6/f6bd32071205516799bcfc4c1e45f12211e521cb.png)

Maybe try with `sudo ls` instead just to double-check.

If none of that works, you will need to do `sudo dmesg` and look for the USB entries on system startup to see what each device has been assigned to.

---

<div class="post-metadata">

**Author:** ![Paul-Reed](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/paul-reed/32/66906_2.png) [@Paul-Reed](https://discourse.nodered.org/u/Paul-Reed)\
**Post date:** [10 October 2023 18:28 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/9 "2023-10-10T18:28:31Z")

</div>

I've attached the result of `sudo dmesg`, but it doesn't make much sense to me 🤨

The last line says -  
`uart-pl011 3f201000.serial: no DMA platform data`  
relevant?

The `serial in` node is showing `not connected`.

```auto
[0.000000] Booting Linux on physical CPU 0x0
[0.000000] Linux version 5.10.103-v7+ (dom@buildbot) (arm-linux-gnueabihf-gcc-8 (Ubuntu/Linaro 8.4.0-3ubuntu1) 8.4.0, GNU ld (GNU Binutils for Ubuntu) 2.34) #1529 SMP Tue Mar 8 12:21:37 GMT 2022
[0.000000] CPU: ARMv7 Processor [410fd034] revision 4 (ARMv7), cr=10c5383d
[0.000000] CPU: div instructions available: patching division code
[0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[0.000000] OF: fdt: Machine model: Raspberry Pi 3 Model B Plus Rev 1.3
[0.000000] random: fast init done
[0.000000] Memory policy: Data cache writealloc
[0.000000] Reserved memory: created CMA memory pool at 0x37400000, size 64 MiB
[0.000000] OF: reserved mem: initialized node linux,cma, compatible id shared-dma-pool
[0.000000] Zone ranges:
[0.000000] DMA [mem 0x0000000000000000-0x000000003b3fffff]
[0.000000] Normal empty
[0.000000] Movable zone start for each node
[0.000000] Early memory node ranges
[0.000000] node 0: [mem 0x0000000000000000-0x000000003b3fffff]
[0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x000000003b3fffff]
[0.000000] On node 0 totalpages: 242688
[0.000000] DMA zone: 2133 pages used for memmap
[0.000000] DMA zone: 0 pages reserved
[0.000000] DMA zone: 242688 pages, LIFO batch:63
[0.000000] percpu: Embedded 20 pages/cpu s50828 r8192 d22900 u81920
[0.000000] pcpu-alloc: s50828 r8192 d22900 u81920 alloc=20*4096
[0.000000] pcpu-alloc: [0] 0 [0] 1 [0] 2 [0] 3
[0.000000] Built 1 zonelists, mobility grouping on. Total pages: 240555
[0.000000] Kernel command line: coherent_pool=1M 8250.nr_uarts=1 snd_bcm2835.enable_compat_alsa=0 snd_bcm2835.enable_hdmi=1 bcm2708_fb.fbwidth=656 bcm2708_fb.fbheight=416 bcm2708_fb.fbswap=1 vc_mem.mem_base=0x3ec00000 vc_mem.mem_size=0x40000000 console=tty1 root=PARTUUID=03749e36-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait quiet splash plymouth.ignore-serial-consoles
[0.000000] Kernel parameter elevator= does not have any effect anymore.
               Please use sysfs to set IO scheduler for individual devices.
[0.000000] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes, linear)
[0.000000] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes, linear)
[0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
[0.000000] Memory: 878804K/970752K available (10240K kernel code, 1312K rwdata, 2952K rodata, 1024K init, 862K bss, 26412K reserved, 65536K cma-reserved)
[0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[0.000000] ftrace: allocating 32081 entries in 95 pages
[0.000000] ftrace: allocated 94 pages with 5 groups
[0.000000] rcu: Hierarchical RCU implementation.
[0.000000] Rude variant of Tasks RCU enabled.
[0.000000] Tracing variant of Tasks RCU enabled.
[0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 10 jiffies.
[0.000000] NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
[0.000000] random: get_random_bytes called from start_kernel+0x3ac/0x580 with crng_init=1
[0.000000] arch_timer: cp15 timer(s) running at 19.20MHz (phys).
[0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x46d987e47, max_idle_ns: 440795202767 ns
[0.000007] sched_clock: 56 bits at 19MHz, resolution 52ns, wraps every 4398046511078ns
[0.000021] Switching to timer-based delay loop, resolution 52ns
[0.000302] Console: colour dummy device 80x30
[0.000374] printk: console [tty1] enabled
[0.000431] Calibrating delay loop (skipped), value calculated using timer frequency.. 38.40 BogoMIPS (lpj=192000)
[0.000459] pid_max: default: 32768 minimum: 301
[0.000664] LSM: Security Framework initializing
[0.000908] Mount-cache hash table entries: 2048 (order: 1, 8192 bytes, linear)
[0.000931] Mountpoint-cache hash table entries: 2048 (order: 1, 8192 bytes, linear)
[0.002372] cgroup: Disabling memory control group subsystem
[0.002636] CPU: Testing write buffer coherency: ok
[0.003134] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
[0.004369] Setting up static identity map for 0x100000 - 0x10003c
[0.004555] rcu: Hierarchical SRCU implementation.
[0.005475] smp: Bringing up secondary CPUs ...
[0.006630] CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
[0.007903] CPU2: thread -1, cpu 2, socket 0, mpidr 80000002
[0.009103] CPU3: thread -1, cpu 3, socket 0, mpidr 80000003
[0.009260] smp: Brought up 1 node, 4 CPUs
[0.009283] SMP: Total of 4 processors activated (153.60 BogoMIPS).
[0.009294] CPU: All CPU(s) started in HYP mode.
[0.009305] CPU: Virtualization extensions available.
[0.010410] devtmpfs: initialized
[0.028301] VFP support v0.3: implementor 41 architecture 3 part 40 variant 3 rev 4
[0.028556] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[0.028586] futex hash table entries: 1024 (order: 4, 65536 bytes, linear)
[0.031660] pinctrl core: initialized pinctrl subsystem
[0.032831] NET: Registered protocol family 16
[0.037179] DMA: preallocated 1024 KiB pool for atomic coherent allocations
[0.042909] audit: initializing netlink subsys (disabled)
[0.043232] audit: type=2000 audit(0.040:1): state=initialized audit_enabled=0 res=1
[0.043814] thermal_sys: Registered thermal governor 'step_wise'
[0.044949] hw-breakpoint: found 5 (+1 reserved) breakpoint and 4 watchpoint registers.
[0.044964] hw-breakpoint: maximum watchpoint size is 8 bytes.
[0.045252] Serial: AMBA PL011 UART driver
[0.063436] bcm2835-mbox 3f00b880.mailbox: mailbox enabled
[0.080119] raspberrypi-firmware soc:firmware: Attached to firmware from 2023-05-09T12:17:54, variant start
[0.090130] raspberrypi-firmware soc:firmware: Firmware hash is 30aa0d70ab280427ba04ebc718c81d4350b9d394
[0.134609] Kprobes globally optimized
[0.139592] bcm2835-dma 3f007000.dma: DMA legacy API manager, dmachans=0x1
[0.141838] SCSI subsystem initialized
[0.142111] usbcore: registered new interface driver usbfs
[0.142176] usbcore: registered new interface driver hub
[0.142247] usbcore: registered new device driver usb
[0.144365] clocksource: Switched to clocksource arch_sys_counter
[1.861130] VFS: Disk quotas dquot_6.6.0
[1.861246] VFS: Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[1.861448] FS-Cache: Loaded
[1.861737] CacheFiles: Loaded
[1.872923] NET: Registered protocol family 2
[1.873199] IP idents hash table entries: 16384 (order: 5, 131072 bytes, linear)
[1.875668] tcp_listen_portaddr_hash hash table entries: 512 (order: 0, 6144 bytes, linear)
[1.875733] TCP established hash table entries: 8192 (order: 3, 32768 bytes, linear)
[1.875851] TCP bind hash table entries: 8192 (order: 4, 65536 bytes, linear)
[1.876043] TCP: Hash tables configured (established 8192 bind 8192)
[1.876231] UDP hash table entries: 512 (order: 2, 16384 bytes, linear)
[1.876289] UDP-Lite hash table entries: 512 (order: 2, 16384 bytes, linear)
[1.876575] NET: Registered protocol family 1
[1.877381] RPC: Registered named UNIX socket transport module.
[1.877394] RPC: Registered udp transport module.
[1.877406] RPC: Registered tcp transport module.
[1.877418] RPC: Registered tcp NFSv4.1 backchannel transport module.
[1.879232] hw perfevents: enabled with armv7_cortex_a7 PMU driver, 7 counters available
[1.882966] Initialise system trusted keyrings
[1.883247] workingset: timestamp_bits=14 max_order=18 bucket_order=4
[1.892795] zbud: loaded
[1.894908] FS-Cache: Netfs 'nfs' registered for caching
[1.895786] NFS: Registering the id_resolver key type
[1.895848] Key type id_resolver registered
[1.895861] Key type id_legacy registered
[1.896018] nfs4filelayout_init: NFSv4 File Layout Driver Registering...
[1.896033] nfs4flexfilelayout_init: NFSv4 Flexfile Layout Driver Registering...
[1.897237] Key type asymmetric registered
[1.897252] Asymmetric key parser 'x509' registered
[1.897306] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 249)
[1.897321] io scheduler mq-deadline registered
[1.897334] io scheduler kyber registered
[1.900848] bcm2708_fb soc:fb: FB found 1 display(s)
[1.908506] Console: switching to colour frame buffer device 82x26
[1.913397] bcm2708_fb soc:fb: Registered framebuffer for display 0, size 656x416
[1.917486] Serial: 8250/16550 driver, 1 ports, IRQ sharing enabled
[1.919751] bcm2835-rng 3f104000.rng: hwrng registered
[1.920187] vc-mem: phys_addr:0x00000000 mem_base=0x3ec00000 mem_size:0x40000000(1024 MiB)
[1.921018] gpiomem-bcm2835 3f200000.gpiomem: Initialised: Registers at 0x3f200000
[1.933290] brd: module loaded
[1.945556] loop: module loaded
[1.947294] Loading iSCSI transport class v2.0-870.
[1.949165] usbcore: registered new interface driver lan78xx
[1.949235] usbcore: registered new interface driver smsc95xx
[1.949261] dwc_otg: version 3.00a 10-AUG-2012 (platform bus)
[2.677534] Core Release: 2.80a
[2.677551] Setting default values for core params
[2.677582] Finished setting default values for core params
[2.877973] Using Buffer DMA mode
[2.877987] Periodic Transfer Interrupt Enhancement - disabled
[2.877999] Multiprocessor Interrupt Enhancement - disabled
[2.878013] OTG VER PARAM: 0, OTG VER FLAG: 0
[2.878040] Dedicated Tx FIFOs mode

[2.878638] WARN::dwc_otg_hcd_init:1074: FIQ DMA bounce buffers: virt = b7514000 dma = 0xf7514000 len=9024
[2.878671] FIQ FSM acceleration enabled for :
               Non-periodic Split Transactions
               Periodic Split Transactions
               High-Speed Isochronous Endpoints
               Interrupt/Control Split Transaction hack enabled
[2.878685] dwc_otg: Microframe scheduler enabled

[2.878756] WARN::hcd_init_fiq:457: FIQ on core 1

[2.878772] WARN::hcd_init_fiq:458: FIQ ASM at 807cb8b8 length 36

[2.878789] WARN::hcd_init_fiq:497: MPHI regs_base at bb810000
[2.878810] dwc_otg 3f980000.usb: DWC OTG Controller
[2.878849] dwc_otg 3f980000.usb: new USB bus registered, assigned bus number 1
[2.878898] dwc_otg 3f980000.usb: irq 89, io mem 0x00000000
[2.878952] Init: Port Power? op_state=1
[2.878964] Init: Power Port (0)
[2.879338] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002, bcdDevice= 5.10
[2.879356] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[2.879371] usb usb1: Product: DWC OTG Controller
[2.879386] usb usb1: Manufacturer: Linux 5.10.103-v7+ dwc_otg_hcd
[2.879400] usb usb1: SerialNumber: 3f980000.usb
[2.880140] hub 1-0:1.0: USB hub found
[2.880218] hub 1-0:1.0: 1 port detected
[2.881441] dwc_otg: FIQ enabled
[2.881453] dwc_otg: NAK holdoff enabled
[2.881465] dwc_otg: FIQ split-transaction FSM enabled
[2.881483] Module dwc_common_port init
[2.881801] usbcore: registered new interface driver usb-storage
[2.882162] mousedev: PS/2 mouse device common for all mice
[2.883342] bcm2835-wdt bcm2835-wdt: Broadcom BCM2835 watchdog timer
[2.886150] sdhci: Secure Digital Host Controller Interface driver
[2.886163] sdhci: Copyright(c) Pierre Ossman
[2.886778] mmc-bcm2835 3f300000.mmcnr: could not get clk, deferring probe
[2.887480] sdhost-bcm2835 3f202000.mmc: could not get clk, deferring probe
[2.887720] sdhci-pltfm: SDHCI platform and OF driver helper
[2.889583] ledtrig-cpu: registered to indicate activity on CPUs
[2.890007] hid: raw HID events driver (C) Jiri Kosina
[2.890175] usbcore: registered new interface driver usbhid
[2.890187] usbhid: USB HID core driver
[2.895560] Initializing XFRM netlink socket
[2.895607] NET: Registered protocol family 17
[2.895769] Key type dns_resolver registered
[2.896530] Registering SWP/SWPB emulation handler
[2.896680] registered taskstats version 1
[2.896710] Loading compiled-in X.509 certificates
[2.897605] Key type ._fscrypt registered
[2.897620] Key type .fscrypt registered
[2.897632] Key type fscrypt-provisioning registered
[2.908742] uart-pl011 3f201000.serial: there is not valid maps for state default
[2.908956] uart-pl011 3f201000.serial: cts_event_workaround enabled
[2.909048] 3f201000.serial: ttyAMA0 at MMIO 0x3f201000 (irq = 114, base_baud = 0) is a PL011 rev2
[2.911404] bcm2835-power bcm2835-power: Broadcom BCM2835 power domains driver
[2.913097] mmc-bcm2835 3f300000.mmcnr: mmc_debug:0 mmc_debug2:0
[2.913114] mmc-bcm2835 3f300000.mmcnr: DMA channel allocated
[2.938534] sdhost: log_buf @ (ptrval) (f7513000)
[2.978325] mmc1: queuing unknown CIS tuple 0x80 (2 bytes)
[2.980004] mmc1: queuing unknown CIS tuple 0x80 (3 bytes)
[2.981701] mmc1: queuing unknown CIS tuple 0x80 (3 bytes)
[2.984711] mmc1: queuing unknown CIS tuple 0x80 (7 bytes)
[2.988569] mmc0: sdhost-bcm2835 loaded - DMA enabled (>1)
[2.991600] of_cfs_init
[2.991851] of_cfs_init: OK
[2.993049] Waiting for root device PARTUUID=03749e36-02...
[3.009564] Indeed it is in host mode hprt0 = 00021501
[3.105486] mmc0: host does not support reading read-only switch, assuming write-enable
[3.109159] mmc0: new high speed SDHC card at address 1234
[3.110196] mmcblk0: mmc0:1234 SA08G 7.21 GiB
[3.113182] mmcblk0: p1 p2
[3.135604] mmc1: new high speed SDIO card at address 0001
[3.148522] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
[3.148620] VFS: Mounted root (ext4 filesystem) readonly on device 179:2.
[3.161613] devtmpfs: mounted
[3.169245] Freeing unused kernel memory: 1024K
[3.194907] Run /sbin/init as init process
[3.194919] with arguments:
[3.194930] /sbin/init
[3.194942] splash
[3.194952] with environment:
[3.194963] HOME=/
[3.194974] TERM=linux
[3.214415] usb 1-1: new high-speed USB device number 2 using dwc_otg
[3.214582] Indeed it is in host mode hprt0 = 00001101
[3.454805] usb 1-1: New USB device found, idVendor=0424, idProduct=2514, bcdDevice= b.b3
[3.454830] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[3.455677] hub 1-1:1.0: USB hub found
[3.455833] hub 1-1:1.0: 4 ports detected
[3.774434] usb 1-1.1: new high-speed USB device number 3 using dwc_otg
[3.904792] usb 1-1.1: New USB device found, idVendor=0424, idProduct=2514, bcdDevice= b.b3
[3.904832] usb 1-1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[3.905655] hub 1-1.1:1.0: USB hub found
[3.905776] hub 1-1.1:1.0: 3 ports detected
[3.947583] systemd[1]: System time before build time, advancing clock.
[4.108393] NET: Registered protocol family 10
[4.109800] Segment Routing with IPv6
[4.216490] systemd[1]: systemd 241 running in system mode. (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD -IDN2 +IDN -PCRE2 default-hierarchy=hybrid)
[4.217472] systemd[1]: Detected architecture arm.
[4.258812] dwc_otg_handle_wakeup_detected_intr lxstate = 2
[4.267073] systemd[1]: Set hostname to <raspberrypi>.
[4.904439] usb 1-1.1.1: new high-speed USB device number 4 using dwc_otg
[5.035042] usb 1-1.1.1: New USB device found, idVendor=0424, idProduct=7800, bcdDevice= 3.00
[5.035068] usb 1-1.1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[5.301215] lan78xx 1-1.1.1:1.0 (unnamed net_device) (uninitialized): No External EEPROM. Setting MAC Speed
[5.325067] lan78xx 1-1.1.1:1.0 (unnamed net_device) (uninitialized): int urb period 64
[5.333047] random: systemd: uninitialized urandom read (16 bytes read)
[5.348680] random: systemd: uninitialized urandom read (16 bytes read)
[5.352437] systemd[1]: Created slice system-systemd\x2dfsck.slice.
[5.352753] random: systemd: uninitialized urandom read (16 bytes read)
[5.352838] systemd[1]: Reached target Swap.
[5.353274] systemd[1]: Started Forward Password Requests to Wall Directory Watch.
[5.354531] systemd[1]: Set up automount Arbitrary Executable File Formats File System Automount Point.
[5.355476] systemd[1]: Listening on udev Control Socket.
[5.356007] systemd[1]: Listening on udev Kernel Socket.
[5.356767] systemd[1]: Listening on Journal Socket (/dev/log).
[5.542718] i2c /dev entries driver
[6.218758] EXT4-fs (mmcblk0p2): re-mounted. Opts: commit=60
[6.385367] systemd-journald[121]: Received request to flush runtime journal from PID 1
[7.617453] vc_sm_cma: module is from the staging directory, the quality is unknown, you have been warned.
[7.620280] bcm2835_vc_sm_cma_probe: Videocore shared memory driver
[7.620309] [vc_sm_connected_init]: start
[7.635717] [vc_sm_connected_init]: installed successfully
[7.655339] mc: Linux media interface: v0.10
[7.723883] videodev: Linux video capture interface: v2.00
[7.807155] bcm2835_mmal_vchiq: module is from the staging directory, the quality is unknown, you have been warned.
[7.809867] bcm2835_mmal_vchiq: module is from the staging directory, the quality is unknown, you have been warned.
[7.810725] bcm2835_mmal_vchiq: module is from the staging directory, the quality is unknown, you have been warned.
[7.846520] bcm2835_isp: module is from the staging directory, the quality is unknown, you have been warned.
[7.853449] bcm2835-isp bcm2835-isp: Device node output[0] registered as /dev/video13
[7.854000] bcm2835-isp bcm2835-isp: Device node capture[0] registered as /dev/video14
[7.854573] bcm2835-isp bcm2835-isp: Device node capture[1] registered as /dev/video15
[7.854994] bcm2835-isp bcm2835-isp: Device node stats[2] registered as /dev/video16
[7.855031] bcm2835-isp bcm2835-isp: Register output node 0 with media controller
[7.855063] bcm2835-isp bcm2835-isp: Register capture node 1 with media controller
[7.855107] bcm2835-isp bcm2835-isp: Register capture node 2 with media controller
[7.855130] bcm2835-isp bcm2835-isp: Register capture node 3 with media controller
[7.855484] bcm2835_v4l2: module is from the staging directory, the quality is unknown, you have been warned.
[7.860027] bcm2835-isp bcm2835-isp: Loaded V4L2 bcm2835-isp
[7.867612] bcm2835_codec: module is from the staging directory, the quality is unknown, you have been warned.
[7.905639] bcm2835-codec bcm2835-codec: Device registered as /dev/video10
[7.905702] bcm2835-codec bcm2835-codec: Loaded V4L2 decode
[7.909127] bcm2835-codec bcm2835-codec: Device registered as /dev/video11
[7.909192] bcm2835-codec bcm2835-codec: Loaded V4L2 encode
[7.914223] bcm2835-codec bcm2835-codec: Device registered as /dev/video12
[7.914280] bcm2835-codec bcm2835-codec: Loaded V4L2 isp
[7.920545] bcm2835-codec bcm2835-codec: Device registered as /dev/video18
[7.920607] bcm2835-codec bcm2835-codec: Loaded V4L2 image_fx
[7.935342] snd_bcm2835: module is from the staging directory, the quality is unknown, you have been warned.
[7.960659] bcm2835_audio bcm2835_audio: card created with 8 channels
[8.038792] cfg80211: Loading compiled-in X.509 certificates for regulatory database
[8.187266] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
[8.209939] cfg80211: loaded regulatory.db is malformed or signature is missing/invalid
[8.279083] brcmfmac: F1 signature read @0x18000000=0x15264345
[8.345053] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43455-sdio for chip BCM4345/6
[8.346057] usbcore: registered new interface driver brcmfmac
[8.578126] random: crng init done
[8.578150] random: 7 urandom warning(s) missed due to ratelimiting
[8.621254] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43455-sdio for chip BCM4345/6
[8.627213] brcmfmac: brcmf_c_preinit_dcmds: Firmware: BCM4345/6 wl0: Nov 1 2021 00:37:25 version 7.45.241 (1a2f2fa CY) FWID 01-703fd60
[11.464778] 8021q: 802.1Q VLAN Support v1.8
[12.213337] brcmfmac: brcmf_cfg80211_set_power_mgmt: power save enabled
[12.691033] 8021q: adding VLAN 0 to HW filter on device eth0
[14.604492] Adding 102396k swap on /var/swap. Priority:-2 extents:10 across:204796k SSFS
[17.858162] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[34.201499] fuse: init (API version 7.32)
[69.046943] uart-pl011 3f201000.serial: no DMA platform data

```

---

<div class="post-metadata">

**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [10 October 2023 19:44 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/10 "2023-10-10T19:44:20Z")

</div>

To me, that looks like it hasn't recognised that there is a USB serial device to load. Which would explain why you don't have `/dev/serial`. It seems to have found several USB hubs though.

Wait! Just gone back to the start of this thread - it is a HAT. So it isn't using USB at all is it?!

OK, that explains things a bit. Looks like I may have somewhat misled you, sorry about that.

Right, rethink. Is it this hat? [sbcshop/SB-RFID-HAT: This is a Raspberry Pi RFID HAT Module operating in the 125Khz frequency range. It supports two communication interfaces: UART for RFID and I2C for Oled Display. (github.com)](https://github.com/sbcshop/SB-RFID-HAT)

IF so, I assume that you've checked that something hasn't reset the serial setting in the Pi config? And have you tried the Python code?

---

<div class="post-metadata">

**Author:** ![Paul-Reed](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/paul-reed/32/66906_2.png) [@Paul-Reed](https://discourse.nodered.org/u/Paul-Reed)\
**Post date:** [10 October 2023 20:20 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/11 "2023-10-10T20:20:24Z")

</div>

> [@TotallyInformation](#):
>
> Right, rethink. Is it this hat?

No, it's one that I bought several years ago from [openenergymonitor](https://shop.openenergymonitor.com/rfm69pi-no-rf/) which is fitted with a RFM69CW 868Mhz radio module.  
The module was returned back to them for checking, and it was working fine, so I think that I can rule out the module & firmware as being the problem.

---

<div class="post-metadata">

**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [10 October 2023 21:30 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/12 "2023-10-10T21:30:07Z")

</div>

Hmm, and all the documentation seems to have moved or gone.

I can only wonder if there are some python tools to test it? Other than that, I'm afraid I'm out of ideas.

---

<div class="post-metadata">

**Author:** ![Paul-Reed](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/paul-reed/32/66906_2.png) [@Paul-Reed](https://discourse.nodered.org/u/Paul-Reed)\
**Post date:** [10 October 2023 21:41 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/13 "2023-10-10T21:41:23Z")

</div>

> [@TotallyInformation](#):
>
> Hmm, and all the documentation seems to have moved or gone.

Well as I've said, it's been tested by the openenergymonitor team (I've seen the test results) and it's a working Hat, so the problem must lay with the Pi.

But thanks for your help Julian.

---

<div class="post-metadata">

**Author:** ![krambriw](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/krambriw/32/5429_2.png) [@krambriw](https://discourse.nodered.org/u/krambriw)\
**Post date:** [11 October 2023 05:44 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/14 "2023-10-11T05:44:14Z")

</div>

Tested it with another Pi? Just to rule out....

---

<div class="post-metadata">

**Author:** ![Paul-Reed](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/paul-reed/32/66906_2.png) [@Paul-Reed](https://discourse.nodered.org/u/Paul-Reed)\
**Post date:** [11 October 2023 18:58 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/15 "2023-10-11T18:58:27Z")

</div>

That will be my next step as I have an old Raspberry Pie v2 in my junk drawer, and am awaiting delivery of a spare SD card.

If it is the pi, it's a perfect excuse to get a Pi 5 🤞

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [10 December 2023 18:59 UTC](https://discourse.nodered.org/t/problem-receiving-rf-data-on-serial-port/81811/16 "2023-12-10T18:59:11Z")

</div>

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.