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HpIpaqH2200CradleMod

Modify your h2200 cradle to provide a serial port

1. Introduction
2. Parts and tools required
3. Procedure
1. Serial cable preparation
2. Cradle preparation
3. Soldering the cable
4. Reassembly
4. What the final result looks like
5. Testing
6. Connecting to the serial console of your Pocket PC
7. Sample of a console boot

1. Introduction

If you can't source some sort of serial cable for your h2200, the cradle can be modified to add what is known as 3-wire null-modem cable, where the TXD and RXD lines are crossed over, and no hardware flow control occurs.

This procedure should be classed as an AT YOUR OWN RISK project. The fine soldering required by this procedure should not be attempted by a novice.

2. Parts and tools required

• DB9M to DB9F serial cable

• Transistor nipper (small side-cutting plier)

• Soldering Iron with small plated tip (25W min.)

• T6 Torx screwdriver

• Multimeter

• A drill or sharp hobby knife

• a small cable-tie

3. Procedure

3.1. Serial cable preparation

Cut off the male plug from the serial cable, and strip about 2cm of the insulation. Prepare the ends of each wire to be connected by stripping approx. 2mm of it's insulation and tinning each one, then retrim the wire to 1-1.5mm.

3.2. Cradle preparation

Open the cradle by undoing the four screws in the base (2 are under the rubber feet). No force is required, however, slight pressure on the black base just above the HP Logo will release the clip underneath.



Once apart, unclip the USB cable from it's socket (it gets in the way). A hole for the serial cable now needs to be cut in the base next to the entry for the USB cable. Thread the cut end of the serial cable into the cradle enclosure.

3.3. Soldering the cable

With the multimeter, find the wires which correspond to pins 2, 3 and 5 on the DB9F.

The diagram below indicates the pin numbering of the female DB9 (the plug with the holes, not the pins!:)


Solder these wires to pads 3, 2 and 5 of the CON103 header on the cradle's board.
(Observing that TXD and RXD are "crossed over".).

DB9F		CON103
2	RXD	TXD	3
3	TXD	RXD	2
5	GND		5

It is best to tin the pads first, and then dab the iron on the wire while it's being held in place. DO NOT OVERHEAT THE SOLDER PADS!!!



Check using a multimeter that adjacent pads are not bridged.

3.3.1. OPTIONAL

By soldering the remaining wires in order, it's possible to enable hardware flow control.
Be aware that this only makes the job harder, and is not a requirement.

3.3.2. Note for those trying to modify a USB-only cradle from another port:

Solder a piece of ribbon cable to likely connector points. Locate signal ground by testing continuity with pin 4 of the USB plug. Measure the voltages on your best guesses. Insert device and boot Linux.

  # cat /dev/urandom > /dev/ttyS0

The TXD line will probably end up being just over 1V rather than +/- 6V (or 0V). RXD will mostly likely be close by TXD, and can be found by experimentation. Once you have likely candidates hooked up with clip leads, try

  # for i in $(seq 10000); do echo -n $i > /dev/ttyS0; done

on the device, and use minicom or hyperterminal on the other end to verify output.

3.4. Reassembly

Slide the board into the upper base being carefull not to move the serial cable too much, as the solder pads may break off the board (particularly if you've overheated your soldering). Carefully move the serial wires to ensure that there is enough room for the screw mount. Secure the end of the serial cable within the cradle, by tightly strapping a cable tie to the insulation of the lead.



Now remove the board, reattach the USB cable, and insert the board into the lower base, carefully placing the power socket into it's locating clip. With short leads on the serial cable, this can be quite tricky, as the power socket can be hard to secure while assembling the wrong way around, so caution and patience are required (or longer, more flexible serial leads ).

4. What the final result looks like

5. Testing

The simplest way to test that the cable "works" is to shove random data out of the host serial port:

  # dd if=/dev/urandom of=/dev/ttyS0

By measuring the voltage between GND (5) and RXD (2) on CON103, both before and after using the dd command, you should be able to detect a voltage change in the order of 60-100 mV. (ie. from, say, 10.6V to 10.66V). Press CTRL+C to halt dd when finished.

The same technique can be used on the Pocket PC end to compare the RXD voltages on the DB9.

6. Connecting to the serial console of your Pocket PC

Start a getty on the Pocket PC. This can be done automatically on boot by adding the following line to /etc/inittab

  S:2345:respawn:/sbin/getty 115200 ttyS0 vt100

A reboot is required (*) to have the getty started. (* simple method)

Start minicom on the host with

  # minicom -s

(you don't need to be root, but you do need privilleges for the port)

Set the port parameters:

A	Serial Device	/dev/ttyS0
B	Lockfile Location	/var/lock
C	Callin Program
D	Callout Program
E	Bps/Par/Bits	115200 8N1
F	Hardware Flow Control	Yes*
G	Software Flow Control	No

* Set Hardware Flow Control to No if you have only soldered a 3-wire interface.

Save the settings as default (handy for later), and restart minicom with

  # minicom -o

Reset your Pocket PC and place it in your new Serial Cradle.

7. Sample of a console boot

Sample output from an old image I had lying around:

Welcome to minicom 2.1

OPTIONS: History Buffer, F-key Macros, Search History Buffer, I18n
Compiled on Nov  4 2005, 18:10:30.

Press CTRL-A Z for help on special keys

Linux version 2.6.13-hh1 (marcus@gentoo) (gcc version 3.4.4) #3 Mon Nov 14 17:05:515CPU: XScale-PXA255 [69052d06] revision 6 (ARMv5TE)
Machine: HP iPAQ H2200
Memory policy: ECC disabled, Data cache writeback
Memory clock: 99.53MHz (*27)
Run Mode clock: 398.13MHz (*4)
Turbo Mode clock: 398.13MHz (*1.0, inactive)
CPU0: D VIVT undefined 5 cache
CPU0: I cache: 32768 bytes, associativity 32, 32 byte lines, 32 sets
CPU0: D cache: 32768 bytes, associativity 32, 32 byte lines, 32 sets
Built 1 zonelists
Kernel command line: root=/dev/mmcblk0p2 noinitrd cachepolicy=writeback console=tty8PID hash table entries: 512 (order: 9, 8192 bytes)
Console: colour dummy device 80x30
Dentry cache hash table entries: 16384 (order: 4, 65536 bytes)
Inode-cache hash table entries: 8192 (order: 3, 32768 bytes)
Memory: 64MB = 64MB total
Memory: 62208KB available (2091K code, 401K data, 96K init)
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
NET: Registered protocol family 16
platform_device_register hamcop
platform_device_register pxa2xx-keys
platform_device_register h2200 battery
platform_device_register pxa2xx-mci
platform_device_register pxa2xx-udc
platform_device_register pxa2xx-fb
platform_device_register pxa2xx-uart
platform_device_register pxa2xx-uart
platform_device_register pxa2xx-uart
platform_device_register pxa2xx-i2c
platform_device_register pxa2xx-i2s
platform_device_register pxa2xx-uart
hamcop: using irq 104-129 on irq 28
platform_device_register samcop adc
platform_device_register hamcop nand
platform_device_register samcop owm
platform_device_register hamcop leds
platform_device_register samcop dma
SAMCOP DMA Driver, (c) 2003-2004 Simtec Electronics
DMA channel 0 at c4902400, irq 120
platform_device_register samcop sdi
Initialising wince bootloader suspend workaround
NetWinder Floating Point Emulator V0.97 (double precision)
JFFS2 version 2.2. (NAND) (C) 2001-2003 Red Hat, Inc.
Initializing Cryptographic API
platform_device_register mq11xx
ttyS0 at MMIO 0x40100000 (irq = 15) is a FFUART
ttyS1 at MMIO 0x40200000 (irq = 14) is a BTUART
ttyS2 at MMIO 0x40700000 (irq = 13) is a STUART
ttyS3 at MMIO 0x41600000 (irq = 0) is a HWUART
io scheduler noop registered
RAMDISK driver initialized: 16 RAM disks of 8192K size 1024 blocksize
Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2
ide: Assuming 50MHz system bus speed for PIO modes; override with idebus=xx
IPAQ flash: probing 32-bit flash bus, window=0
Probe at base[0x00](0x00000000) past the end of the map(0xffffffff)
Probe at base[0x00](0x00000000) past the end of the map(0xffffffff)
Probe at base[0x00](0x00000000) past the end of the map(0xffffffff)
NAND device: Manufacturer ID: 0xec, Chip ID: 0x75 (Samsung NAND 32MiB 3,3V 8-bit)
Scanning device for bad blocks
Using builtin partition definition
Creating 4 MTD partitions on "NAND 32MiB 3,3V 8-bit":
0x00000000-0x00004000 : "HTC first-stage bootstrap"
0x00004000-0x00028000 : "HTC rescue bootloader"
0x00028000-0x00168000 : "second-stage loader"
0x00168000-0x02000000 : "root fs"
platform_device_register pxa2xx-pcmcia
pxa2xx_udc: version 4-May-2005
usb0: Ethernet Gadget, version: May Day 2005
usb0: using pxa2xx_udc, OUT ep2out-bulk IN ep1in-bulk
usb0: MAC 96:eb:f6:2e:9d:e6
i2c /dev entries driver
I2C: i2c-0: PXA I2C adapter
dmabounce: registered device samcop sdi on platform bus
samcop sdi: probe: irq=124 irq_cd=31 dma=0.
samcop sdi: initialisation done.
platform_device_register mq11xx_fb
platform_device_register mq11xx_lcd
platform_device_register mq11xx_udc
platform_device_register mq11xx_uhc
MediaQ 1188 chip detected, base IRQ 130
NET: Registered protocol family 2
mmc0: host does not support reading read-only switch. assuming write-enable.
mmcblk0: mmc0:a95c SD512 495488KiB
 mmcblk0: p1 p2
IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
TCP established hash table entries: 4096 (order: 3, 32768 bytes)
TCP bind hash table entries: 4096 (order: 2, 16384 bytes)
TCP: Hash tables configured (established 4096 bind 4096)
TCP reno registered
TCP bic registered
NET: Registered protocol family 1
NET: Registered protocol family 17
EXT2-fs warning: mounting unchecked fs, running e2fsck is recommended
VFS: Mounted root (ext2 filesystem).
Freeing init memory: 96K
INIT: version 2.86 booting
mount: Mounting proc on /proc failed: Device or resource busy
chvt: Couldn't get a file descriptor referring to the console
chvt: VT_ACTIVATE: Bad file descriptor
Creating initial device nodes...
mount: Mounting usbdevfs on /proc/bus/usb failed: No such device
umount: /proc/bus/usb: Invalid argument
Setting up IP spoofing protection: rp_filter.
Configuring network interfaces... SIOCSIFADDR: No such device
SIOCSIFNETMASK: No such device
SIOCSIFBRDADDR: No such device
SIOCGIFFLAGS: No such device
route: SIOC[ADD|DEL]RT: No such device
done.
Starting portmap daemon: portmap.
Turning echo off on /dev/tts/3
Configuring h2200-bootloader
FATAL: Module mtdblock not found.
postinst script returned status 1
ERROR: h2200-bootloader.postinst returned 1
Nothing to be done
INIT: Entering runlevel: 5
Starting Dropbear SSH server: dropbear.
Starting advanced power management daemon: apmd[2206]: apmd 3.2.1 interfacing with 2apmd.
Removing stale PID file /var/run/dbus/pid.
Starting system message bus: dbus-1.
Starting irattach: .
Starting lirc daemon: lircdlircd 0.7.1: WARNING: config file contains no valid remon.
Starting PCMCIA services: modprobe: WARNING: Error inserting crc_ccitt (/lib/modulet
cardmgr[2320]: watching 1 socket
done.
Starting Samba: smbd nmbd.
Starting syslogd/klogd: done
Starting Bluetooth subsystem: hcid sdpd hidd hid2hci rfcomm pand.
Starting at daemon: atd.
Starting GPE display manager: gpe-dm

Familiar Linux v0.8.3-prerelease-snapshot-20051025 h2200 tts/0

h2200 login:

MoinMoin Powered

Immutable page (last edited 2007-05-28 03:58:49 by MarcusBrown)

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