vthielen
Posts: 35
Joined: Wed Mar 05, 2014 9:32 am

using uart on RPI B+ with jessie

Thu Jan 25, 2018 9:07 am

Due to a slight change in the RPI B+ rev1.2 (Hynix memory) my old image won't boot on a new RPI B+, so I decided to restart with a jessie image.
On the previous version the UART (coming out on pins 8 and 10 at the RPI header) worked very well, but on this one (Linux version 4.4.21+ with Jessie image) I cannot get it to work.

I have added the following three lines, by themselves or in combinations to the /boot/config.txt:
enable_uart=1
dtparam=uart1=on
dtoverlay=uart1,txd1_pin=14,rxd1_pin=15

But after rebooting the pins still stay assigned as normal IO:
root@WP0050:~# raspi-gpio get 14
GPIO 14: level=1 fsel=0 func=INPUT

What would it take to connect the UART?

I have some other IO's as well, maybe it's best to make an overlay for the application?
Where can I find explanation how to do this?
Or is there a way to go back to the old style, because these RPI's will only be used for this application anyway?

PhilE
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1734
Joined: Mon Sep 29, 2014 1:07 pm
Location: Cambridge

Re: using uart on RPI B+ with jessie

Thu Jan 25, 2018 9:23 am

Which UART are you trying to use? There are two.

* uart0 is a pl011, also known as /dev/ttyAMA0.
* uart1 is an 8250 clone, also known as the mini-UART and /dev/ttyS0.

UART0 is the natural UART to use on any Pi without on-board Bluetooth - with no config.txt settings it will be enabled by default (enable_uart=1 unless you change it).
UART0 is (by default) used for Bluetooth on Pi 3 and Pi Zero W, so UART1 is the free UART. UART1 has smaller FIFOs, dodgy flow control and has a clock derived from the core/VPU clock, so making use of it requires fixing the VPU clock to 250MHz. enable_uart=0 by default on these Pis - changing it to 1 will also lock the core to 250MHz.

You can't use both UARTs on a non-BT Pi other than a Compute Module, so do yourself a favour and remove those config.txt settings (you can leave enable_uart=1, although it is unnecessary) and use /dev/serial0 (an alias to the primary, console UART - UART0/ttyAMA0 on non-BT Pis, UART1/ttyS0 on BT Pis).

And on the subject of doing yourself a favour, why would you choose Jessie when starting a new image? Our Stretch releases are better in many ways.

vthielen
Posts: 35
Joined: Wed Mar 05, 2014 9:32 am

Re: using uart on RPI B+ with jessie

Thu Jan 25, 2018 12:35 pm

thanks for the reply,

I am using jessie because have another application that was written already for the 'hynix' version a while ago, which uses a lot of the same libraries and settings as the one I am trying to get working now.
That is why I am trying to start from that image.

I want to use the pl011 uart (/dev/ttyAMA0), which is the one I was using before.
How do I tell the PI B+ to connect that to pins 8 and 10, instead of standard IO?

Or is there a way to make the old image boot on a RPI 1 B+ V1.2 with the Hynix memory chip?
A lot of time has gone in to configuring, developing and testing this application, so I would like to change as little as possible, to avoid introducing new bugs.

PhilE
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1734
Joined: Mon Sep 29, 2014 1:07 pm
Location: Cambridge

Re: using uart on RPI B+ with jessie

Thu Jan 25, 2018 12:49 pm

The firmware and kernel packages shipped with Jessie should enable UART0 automatically on a B+ unless there is something in your config.txt preventing it. It might be worth uploading config.txt and the output from "dmesg" after booting.

vthielen
Posts: 35
Joined: Wed Mar 05, 2014 9:32 am

Re: using uart on RPI B+ with jessie

Thu Jan 25, 2018 4:24 pm

Content of /boot/config.txt is:

# For more options and information see
# http://www.raspberrypi.org/documentatio ... fig-txt.md
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
#disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=1
#hdmi_mode=1

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2s=on
#dtparam=spi=on

# Uncomment this to enable the lirc-rpi module
#dtoverlay=lirc-rpi

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

enable_uart=1
#dtparam=uart1=on
#dtoverlay=uart1,txd1_pin=14,rxd1_pin=15




The output of dmesg is:

[ 0.000000] Booting Linux on physical CPU 0x0
[ 0.000000] Initializing cgroup subsys cpuset
[ 0.000000] Initializing cgroup subsys cpu
[ 0.000000] Initializing cgroup subsys cpuacct
[ 0.000000] Linux version 4.4.21+ (dc4@dc4-XPS13-9333) (gcc version 4.9.3 (crosstool-NG crosstool-ng-1.22.0-88-g8460611) ) #911 Thu Sep 15 14:17:52 BST 2016
[ 0.000000] CPU: ARMv6-compatible processor [410fb767] revision 7 (ARMv7), cr=00c5387d
[ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT nonaliasing instruction cache
[ 0.000000] Machine model: Raspberry Pi Model B Plus Rev 1.2
[ 0.000000] cma: Reserved 8 MiB at 0x1b400000
[ 0.000000] Memory policy: Data cache writeback
[ 0.000000] On node 0 totalpages: 114688
[ 0.000000] free_area_init_node: node 0, pgdat c08823cc, node_mem_map db010000
[ 0.000000] Normal zone: 1008 pages used for memmap
[ 0.000000] Normal zone: 0 pages reserved
[ 0.000000] Normal zone: 114688 pages, LIFO batch:31
[ 0.000000] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
[ 0.000000] pcpu-alloc: [0] 0
[ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 113680
[ 0.000000] Kernel command line: dma.dmachans=0x7f35 bcm2708_fb.fbwidth=656 bcm2708_fb.fbheight=416 bcm2708.boardrev=0x900032 bcm2708.serial=0x2173b904 smsc95xx.macaddr=B8:27:EB:73:B9:04 bcm2708_fb.fbswap=1 bcm2708.uart_clock=48000000 bcm2708.disk_led_gpio=47 bcm2708.disk_led_active_low=0 vc_mem.mem_base=0x1ec00000 vc_mem.mem_size=0x20000000 dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait quiet splash plymouth.ignore-serial-consoles
[ 0.000000] PID hash table entries: 2048 (order: 1, 8192 bytes)
[ 0.000000] Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)
[ 0.000000] Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)
[ 0.000000] Memory: 436524K/458752K available (6055K kernel code, 437K rwdata, 1844K rodata, 380K init, 726K bss, 14036K reserved, 8192K cma-reserved)
[ 0.000000] Virtual kernel memory layout:
vector : 0xffff0000 - 0xffff1000 ( 4 kB)
fixmap : 0xffc00000 - 0xfff00000 (3072 kB)
vmalloc : 0xdc800000 - 0xff800000 ( 560 MB)
lowmem : 0xc0000000 - 0xdc000000 ( 448 MB)
modules : 0xbf000000 - 0xc0000000 ( 16 MB)
.text : 0xc0008000 - 0xc07beee0 (7900 kB)
.init : 0xc07bf000 - 0xc081e000 ( 380 kB)
.data : 0xc081e000 - 0xc088b490 ( 438 kB)
.bss : 0xc088b490 - 0xc0941050 ( 727 kB)
[ 0.000000] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[ 0.000000] NR_IRQS:16 nr_irqs:16 16
[ 0.000027] sched_clock: 32 bits at 1000kHz, resolution 1000ns, wraps every 2147483647500ns
[ 0.000069] clocksource: timer: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 1911260446275 ns
[ 0.000168] bcm2835: system timer (irq = 27)
[ 0.000479] Console: colour dummy device 80x30
[ 0.000716] console [tty1] enabled
[ 0.000747] Calibrating delay loop... 697.95 BogoMIPS (lpj=3489792)
[ 0.060302] pid_max: default: 32768 minimum: 301
[ 0.060677] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.060706] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.061713] Disabling cpuset control group subsystem
[ 0.061762] Initializing cgroup subsys io
[ 0.061797] Initializing cgroup subsys memory
[ 0.061855] Initializing cgroup subsys devices
[ 0.061885] Initializing cgroup subsys freezer
[ 0.061913] Initializing cgroup subsys net_cls
[ 0.061996] CPU: Testing write buffer coherency: ok
[ 0.062074] ftrace: allocating 20629 entries in 61 pages
[ 0.173180] Setting up static identity map for 0x81c0 - 0x81f8
[ 0.175077] devtmpfs: initialized
[ 0.184611] VFP support v0.3: implementor 41 architecture 1 part 20 variant b rev 5
[ 0.185137] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[ 0.186891] pinctrl core: initialized pinctrl subsystem
[ 0.187768] NET: Registered protocol family 16
[ 0.193503] DMA: preallocated 4096 KiB pool for atomic coherent allocations
[ 0.202102] hw-breakpoint: found 6 breakpoint and 1 watchpoint registers.
[ 0.202131] hw-breakpoint: maximum watchpoint size is 4 bytes.
[ 0.202314] Serial: AMBA PL011 UART driver
[ 0.202727] 20201000.uart: ttyAMA0 at MMIO 0x20201000 (irq = 81, base_baud = 0) is a PL011 rev2
[ 0.203595] bcm2835-mbox 2000b880.mailbox: mailbox enabled
[ 0.247698] bcm2835-dma 20007000.dma: DMA legacy API manager at f2007000, dmachans=0x1
[ 0.248586] SCSI subsystem initialized
[ 0.248915] usbcore: registered new interface driver usbfs
[ 0.249048] usbcore: registered new interface driver hub
[ 0.249255] usbcore: registered new device driver usb
[ 0.253084] raspberrypi-firmware soc:firmware: Attached to firmware from 2016-09-21 13:13
[ 0.280942] clocksource: Switched to clocksource timer
[ 0.333215] FS-Cache: Loaded
[ 0.333644] CacheFiles: Loaded
[ 0.353053] NET: Registered protocol family 2
[ 0.354404] TCP established hash table entries: 4096 (order: 2, 16384 bytes)
[ 0.354506] TCP bind hash table entries: 4096 (order: 2, 16384 bytes)
[ 0.354608] TCP: Hash tables configured (established 4096 bind 4096)
[ 0.354714] UDP hash table entries: 256 (order: 0, 4096 bytes)
[ 0.354753] UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
[ 0.355116] NET: Registered protocol family 1
[ 0.355734] RPC: Registered named UNIX socket transport module.
[ 0.355760] RPC: Registered udp transport module.
[ 0.355772] RPC: Registered tcp transport module.
[ 0.355783] RPC: Registered tcp NFSv4.1 backchannel transport module.
[ 0.357192] hw perfevents: enabled with armv6_1176 PMU driver, 3 counters available
[ 0.358623] futex hash table entries: 256 (order: -1, 3072 bytes)
[ 0.375118] VFS: Disk quotas dquot_6.6.0
[ 0.375533] VFS: Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[ 0.378234] FS-Cache: Netfs 'nfs' registered for caching
[ 0.379580] NFS: Registering the id_resolver key type
[ 0.379672] Key type id_resolver registered
[ 0.379689] Key type id_legacy registered
[ 0.384059] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 252)
[ 0.384479] io scheduler noop registered
[ 0.384517] io scheduler deadline registered (default)
[ 0.384913] io scheduler cfq registered
[ 0.387714] BCM2708FB: allocated DMA memory 5b800000
[ 0.387792] BCM2708FB: allocated DMA channel 0 @ f2007000
[ 0.395900] Console: switching to colour frame buffer device 82x26
[ 1.452343] bcm2835-rng 20104000.rng: hwrng registered
[ 1.452650] vc-cma: Videocore CMA driver
[ 1.452672] vc-cma: vc_cma_base = 0x00000000
[ 1.452686] vc-cma: vc_cma_size = 0x00000000 (0 MiB)
[ 1.452698] vc-cma: vc_cma_initial = 0x00000000 (0 MiB)
[ 1.453091] vc-mem: phys_addr:0x00000000 mem_base=0x1ec00000 mem_size:0x20000000(512 MiB)
[ 1.478125] brd: module loaded
[ 1.490330] loop: module loaded
[ 1.491581] vchiq: vchiq_init_state: slot_zero = 0xdb880000, is_master = 0
[ 1.493953] Loading iSCSI transport class v2.0-870.
[ 1.495243] usbcore: registered new interface driver smsc95xx
[ 1.495356] dwc_otg: version 3.00a 10-AUG-2012 (platform bus)
[ 1.696103] Core Release: 2.80a
[ 1.696139] Setting default values for core params
[ 1.696189] Finished setting default values for core params
[ 1.896547] Using Buffer DMA mode
[ 1.896574] Periodic Transfer Interrupt Enhancement - disabled
[ 1.896588] Multiprocessor Interrupt Enhancement - disabled
[ 1.896601] OTG VER PARAM: 0, OTG VER FLAG: 0
[ 1.896699] Dedicated Tx FIFOs mode
[ 1.897270] WARN::dwc_otg_hcd_init:1047: FIQ DMA bounce buffers: virt = 0xdb814000 dma = 0x5b814000 len=9024
[ 1.897310] FIQ FSM acceleration enabled for :
Non-periodic Split Transactions
Periodic Split Transactions
High-Speed Isochronous Endpoints
Interrupt/Control Split Transaction hack enabled
[ 1.897346] dwc_otg: Microframe scheduler enabled
[ 1.897426] WARN::hcd_init_fiq:413: FIQ on core 0 at 0xc0408ab8
[ 1.897448] WARN::hcd_init_fiq:414: FIQ ASM at 0xc0408d94 length 36
[ 1.897480] WARN::hcd_init_fiq:439: MPHI regs_base at 0xdc898000
[ 1.897557] dwc_otg 20980000.usb: DWC OTG Controller
[ 1.897624] dwc_otg 20980000.usb: new USB bus registered, assigned bus number 1
[ 1.897702] dwc_otg 20980000.usb: irq 56, io mem 0x00000000
[ 1.897764] Init: Port Power? op_state=1
[ 1.897777] Init: Power Port (0)
[ 1.898156] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
[ 1.898182] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 1.898200] usb usb1: Product: DWC OTG Controller
[ 1.898217] usb usb1: Manufacturer: Linux 4.4.21+ dwc_otg_hcd
[ 1.898233] usb usb1: SerialNumber: 20980000.usb
[ 1.899430] hub 1-0:1.0: USB hub found
[ 1.899536] hub 1-0:1.0: 1 port detected
[ 1.900469] dwc_otg: FIQ enabled
[ 1.900492] dwc_otg: NAK holdoff enabled
[ 1.900504] dwc_otg: FIQ split-transaction FSM enabled
[ 1.900558] Module dwc_common_port init
[ 1.901199] usbcore: registered new interface driver usb-storage
[ 1.901753] mousedev: PS/2 mouse device common for all mice
[ 1.902957] bcm2835-cpufreq: min=700000 max=700000
[ 1.903379] sdhci: Secure Digital Host Controller Interface driver
[ 1.903399] sdhci: Copyright(c) Pierre Ossman
[ 1.903900] sdhost: log_buf @ db813000 (5b813000)
[ 1.961024] mmc0: sdhost-bcm2835 loaded - DMA enabled (>1)
[ 1.961594] sdhci-pltfm: SDHCI platform and OF driver helper
[ 1.962483] ledtrig-cpu: registered to indicate activity on CPUs
[ 1.962805] hidraw: raw HID events driver (C) Jiri Kosina
[ 1.963125] usbcore: registered new interface driver usbhid
[ 1.963143] usbhid: USB HID core driver
[ 1.984229] Initializing XFRM netlink socket
[ 1.984297] NET: Registered protocol family 17
[ 1.984520] Key type dns_resolver registered
[ 1.986641] registered taskstats version 1
[ 1.986965] vc-sm: Videocore shared memory driver
[ 1.986991] [vc_sm_connected_init]: start
[ 1.988018] [vc_sm_connected_init]: end - returning 0
[ 1.988659] of_cfs_init
[ 1.988820] of_cfs_init: OK
[ 1.990252] Waiting for root device /dev/mmcblk0p2...
[ 2.029614] mmc0: host does not support reading read-only switch, assuming write-enable
[ 2.032950] mmc0: new high speed SDHC card at address 0007
[ 2.033981] mmcblk0: mmc0:0007 SD08G 7.42 GiB
[ 2.035704] mmcblk0: p1 p2
[ 2.091719] Indeed it is in host mode hprt0 = 00021501
[ 2.167018] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
[ 2.167142] VFS: Mounted root (ext4 filesystem) readonly on device 179:2.
[ 2.177622] devtmpfs: mounted
[ 2.178944] Freeing unused kernel memory: 380K (c07bf000 - c081e000)
[ 2.271064] usb 1-1: new high-speed USB device number 2 using dwc_otg
[ 2.271364] Indeed it is in host mode hprt0 = 00001101
[ 2.471540] usb 1-1: New USB device found, idVendor=0424, idProduct=9514
[ 2.471598] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[ 2.472878] hub 1-1:1.0: USB hub found
[ 2.473048] hub 1-1:1.0: 5 ports detected
[ 2.581666] random: systemd: uninitialized urandom read (16 bytes read, 56 bits of entropy available)
[ 2.589536] systemd[1]: systemd 215 running in system mode. (+PAM +AUDIT +SELINUX +IMA +SYSVINIT +LIBCRYPTSETUP +GCRYPT +ACL +XZ -SECCOMP -APPARMOR)
[ 2.590283] systemd[1]: Detected architecture 'arm'.
[ 2.715210] NET: Registered protocol family 10
[ 2.717115] systemd[1]: Inserted module 'ipv6'
[ 2.719956] systemd[1]: Set hostname to <WP0050>.
[ 2.751127] usb 1-1.1: new high-speed USB device number 3 using dwc_otg
[ 2.851679] usb 1-1.1: New USB device found, idVendor=0424, idProduct=ec00
[ 2.851717] usb 1-1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[ 2.855050] smsc95xx v1.0.4
[ 2.919805] smsc95xx 1-1.1:1.0 eth0: register 'smsc95xx' at usb-20980000.usb-1.1, smsc95xx USB 2.0 Ethernet, b8:27:eb:73:b9:04
[ 2.936418] random: systemd-sysv-ge: uninitialized urandom read (16 bytes read, 74 bits of entropy available)
[ 3.100748] random: systemd: uninitialized urandom read (16 bytes read, 76 bits of entropy available)
[ 3.102916] random: systemd: uninitialized urandom read (16 bytes read, 76 bits of entropy available)
[ 3.105181] random: systemd: uninitialized urandom read (16 bytes read, 76 bits of entropy available)
[ 3.129829] random: systemd: uninitialized urandom read (16 bytes read, 76 bits of entropy available)
[ 3.135326] random: systemd: uninitialized urandom read (16 bytes read, 76 bits of entropy available)
[ 3.135786] random: systemd: uninitialized urandom read (16 bytes read, 76 bits of entropy available)
[ 3.204066] random: systemd: uninitialized urandom read (16 bytes read, 77 bits of entropy available)
[ 3.206538] random: systemd: uninitialized urandom read (16 bytes read, 77 bits of entropy available)
[ 3.428116] systemd[1]: Starting Forward Password Requests to Wall Directory Watch.
[ 3.429141] systemd[1]: Started Forward Password Requests to Wall Directory Watch.
[ 3.429394] systemd[1]: Starting Remote File Systems (Pre).
[ 3.429879] systemd[1]: Reached target Remote File Systems (Pre).
[ 3.430293] systemd[1]: Starting Arbitrary Executable File Formats File System Automount Point.
[ 3.431548] systemd[1]: Set up automount Arbitrary Executable File Formats File System Automount Point.
[ 3.431823] systemd[1]: Starting Encrypted Volumes.
[ 3.432020] systemd[1]: Reached target Encrypted Volumes.
[ 3.432256] systemd[1]: Starting Swap.
[ 3.432442] systemd[1]: Reached target Swap.
[ 3.432644] systemd[1]: Expecting device dev-mmcblk0p1.device...
[ 3.432848] systemd[1]: Starting Root Slice.
[ 3.433202] systemd[1]: Created slice Root Slice.
[ 3.433404] systemd[1]: Starting User and Session Slice.
[ 3.433966] systemd[1]: Created slice User and Session Slice.
[ 3.434178] systemd[1]: Starting Delayed Shutdown Socket.
[ 3.434612] systemd[1]: Listening on Delayed Shutdown Socket.
[ 3.434823] systemd[1]: Starting /dev/initctl Compatibility Named Pipe.
[ 3.435310] systemd[1]: Listening on /dev/initctl Compatibility Named Pipe.
[ 3.435523] systemd[1]: Starting Journal Socket (/dev/log).
[ 3.436029] systemd[1]: Listening on Journal Socket (/dev/log).
[ 3.436313] systemd[1]: Starting udev Control Socket.
[ 3.436781] systemd[1]: Listening on udev Control Socket.
[ 3.437047] systemd[1]: Starting udev Kernel Socket.
[ 3.437415] systemd[1]: Listening on udev Kernel Socket.
[ 3.437671] systemd[1]: Starting Journal Socket.
[ 3.438185] systemd[1]: Listening on Journal Socket.
[ 3.438580] systemd[1]: Starting System Slice.
[ 3.439190] systemd[1]: Created slice System Slice.
[ 3.439560] systemd[1]: Starting File System Check on Root Device...
[ 3.445728] systemd[1]: Starting system-systemd\x2dfsck.slice.
[ 3.446560] systemd[1]: Created slice system-systemd\x2dfsck.slice.
[ 3.446905] systemd[1]: Starting system-autologin.slice.
[ 3.447742] systemd[1]: Created slice system-autologin.slice.
[ 3.448297] systemd[1]: Starting Increase datagram queue length...
[ 3.463926] systemd[1]: Starting Restore / save the current clock...
[ 3.485841] systemd[1]: Mounted Huge Pages File System.
[ 3.486196] systemd[1]: Starting udev Coldplug all Devices...
[ 3.526112] systemd[1]: Mounting Debug File System...
[ 3.585711] systemd[1]: Started Set Up Additional Binary Formats.
[ 3.586707] systemd[1]: Starting Create list of required static device nodes for the current kernel...
[ 3.622739] systemd[1]: Mounting POSIX Message Queue File System...
[ 3.783550] systemd[1]: Starting Load Kernel Modules...
[ 3.789618] systemd[1]: Starting Slices.
[ 3.789842] systemd[1]: Reached target Slices.
[ 3.875477] systemd[1]: Mounted Debug File System.
[ 3.878675] systemd[1]: Started Increase datagram queue length.
[ 3.917820] systemd[1]: Started Restore / save the current clock.
[ 3.988107] fuse init (API version 7.23)
[ 3.989712] systemd[1]: Started Create list of required static device nodes for the current kernel.
[ 3.997120] systemd[1]: Started File System Check on Root Device.
[ 3.998729] systemd[1]: Mounted POSIX Message Queue File System.
[ 4.009160] i2c /dev entries driver
[ 4.018782] systemd[1]: Started Load Kernel Modules.
[ 4.019583] systemd[1]: Time has been changed
[ 4.192328] systemd[1]: Started udev Coldplug all Devices.
[ 4.372936] systemd[1]: Mounting FUSE Control File System...
[ 4.379766] systemd[1]: Mounting Configuration File System...
[ 4.390465] systemd[1]: Starting Apply Kernel Variables...
[ 4.417530] systemd[1]: Starting Create Static Device Nodes in /dev...
[ 4.443873] systemd[1]: Starting Syslog Socket.
[ 4.444456] systemd[1]: Listening on Syslog Socket.
[ 4.444868] systemd[1]: Starting Journal Service...
[ 4.536158] systemd[1]: Started Journal Service.
[ 4.931443] systemd-udevd[116]: starting version 215
[ 6.781291] bcm2835-wdt 20100000.watchdog: Broadcom BCM2835 watchdog timer
[ 6.921203] gpiomem-bcm2835 20200000.gpiomem: Initialised: Registers at 0x20200000
[ 6.946549] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)
[ 9.900175] systemd-journald[111]: Received request to flush runtime journal from PID 1
[ 15.219679] cfg80211: World regulatory domain updated:
[ 15.219723] cfg80211: DFS Master region: unset
[ 15.219739] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
[ 15.219763] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (N/A, 2000 mBm), (N/A)
[ 15.219781] cfg80211: (2457000 KHz - 2482000 KHz @ 40000 KHz), (N/A, 2000 mBm), (N/A)
[ 15.219801] cfg80211: (2474000 KHz - 2494000 KHz @ 20000 KHz), (N/A, 2000 mBm), (N/A)
[ 15.219823] cfg80211: (5170000 KHz - 5250000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2000 mBm), (N/A)
[ 15.219842] cfg80211: (5250000 KHz - 5330000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2000 mBm), (0 s)
[ 15.219860] cfg80211: (5490000 KHz - 5730000 KHz @ 160000 KHz), (N/A, 2000 mBm), (0 s)
[ 15.219876] cfg80211: (5735000 KHz - 5835000 KHz @ 80000 KHz), (N/A, 2000 mBm), (N/A)
[ 15.219892] cfg80211: (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 0 mBm), (N/A)
[ 16.436529] Adding 102396k swap on /var/swap. Priority:-1 extents:4 across:192508k SSFS
[ 17.871073] random: nonblocking pool is initialized
[ 18.947206] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup
[ 18.957977] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[ 20.512554] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0x43E1
[ 20.524926] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
[ 32.226551] Bluetooth: Core ver 2.21
[ 32.232893] NET: Registered protocol family 31
[ 32.232926] Bluetooth: HCI device and connection manager initialized
[ 32.232963] Bluetooth: HCI socket layer initialized
[ 32.232994] Bluetooth: L2CAP socket layer initialized
[ 32.233054] Bluetooth: SCO socket layer initialized
[ 32.331578] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[ 32.331654] Bluetooth: BNEP filters: protocol multicast
[ 32.331762] Bluetooth: BNEP socket layer initialized
[ 64.930701] gpiomem-bcm2835 20200000.gpiomem: gpiomem device opened.
[ 65.004729] gpiomem-bcm2835 20200000.gpiomem: gpiomem device opened.
[ 96.885367] gpiomem-bcm2835 20200000.gpiomem: gpiomem device opened.

PhilE
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1734
Joined: Mon Sep 29, 2014 1:07 pm
Location: Cambridge

Re: using uart on RPI B+ with jessie

Thu Jan 25, 2018 4:59 pm

A fresh install of the 2016-09-23 Jessie image (this matches your kernel) on a B+ gives me UART0 mapped to GPIOs 14 & 15. No configuration changes are needed. Adding "enable_uart=1" doesn't change anything.

If you have a spare card, try a clean install and verify that you get the same results.

vthielen
Posts: 35
Joined: Wed Mar 05, 2014 9:32 am

Re: using uart on RPI B+ with jessie

Fri Jan 26, 2018 4:14 pm

I decided to start from the latest image (will have to do so sooner or later anyway)
On this one the UART is ok by default:

root@raspberrypi:~# raspi-gpio get 14
GPIO 14: level=1 fsel=4 alt=0 func=TXD0

thanks for the help anyway,

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