Problem receiving RF data on serial port

General
1

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?

2

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.

1 Like
3

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.

How could I check?

4

image
image884Ă—58 4.27 KB

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
image1175Ă—113 7.08 KB

1 Like
5

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

6

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.

1 Like
7

I'm getting;

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

8

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

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.

9

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

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

The serial in node is showing not connected.

[    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
10

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)

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?

11

No, it's one that I bought several years ago from openenergymonitor 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.

12

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.

13

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.

14

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

15

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 :crossed_fingers:

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16

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