Agenda VR3's Notes

Sun Ge

Revision History
Revision 0.2<>SG

Table of Contents

Basic Usage
Use VR3 as a Serial Terminal
Use VR3 as a Ebook Reader (Chinese supported)
Hardware Hack
Upgrade SDRAM
Programming VR3

Agenda VR3 is a PDA with VR4181 CPU, 16MB Flash ROM and 8MB SDRAM. It's distributed since 2001 with a custom Linux kernel and X window.

Now Agenda VR3 seems obsolete, but we can use it as:

Agenda Wiki contains almost all topics about Agenda VR3, including faq and howtos.

Basic Usage


Agenda VR3 can upload/download files through infrared or serial cable.

PPP over InfraRed

On Zaurus C1000 or Linux PC which have a infrared adapter:

$pppd /dev/ircomm 115200 noauth nodetach novj debug local

It will set local IP and set remote IP, then follow the procedure on Agenda VR3 quickly:

Network-->direct serial-->IrComm Direct-->start

PPP over serial cable(quicksync cable)

On Linux PC,

$pppd /dev/ttyUSB0 115200 noauth nodetach novj debug local

It will set local IP and set remote IP, then follow the procedure on Agenda VR3 quickly:

Network-->direct serial-->serial direct-->start

ppp start

Using rsync to download/upload files

On Linux PC, add a line in /etc/hosts: agenda agenda

Then get network available through PPP over infrared or serial cable.

Now we can rsync files between PC and Agenda VR3, for example:

$rsync foo.txt agenda::default

foo.txt will be sent to /home/default/ of VR3. There is another example:

$rsync foo.rc agenda::root/etc/

foo.rc will be sent to /etc/ of VR3.

In order to download files from Agenda VR3, for example:

$rsync agenda::root/home/default/bar.dat .

bar.dat will be downloaded form agenda to current directory of PC.


On linux PC, you can get PPP on and telnet to Agenda VR3.

$telnet agenda

Use VR3's X server

You can run X client programs in your PC and read/write input/output from/to X server of Agenda VR3. At first, X server's access should be allowed:

On Agenda VR3, edit /etc/hosts:       localhost        laptop

laptop is the name of your PC.

Then edit /etc/X0.hosts:


Now you can connect to Agenda VR3's X server from PC. For example, to get a screen shot of VR3:

$DISPLAY=agenda:0 import -window root screenshot.gif

Another example, to run xterm or other programs to VR3's X server:

$DISPLAY=agenda:0 xterm
$DISPLAY=agenda:0 xpdf
$DISPLAY=agenda:0 ...

xpdf on vr3's X server

Use VR3 as a Serial Terminal

Install microcom

On Agenda VR3, copy microcom-serial.snow to /usr/local/bin/ and make it belong to root and have permission 4755.

then cd to /home/default/.wmx/System, write a executable script named Microcom:

#Microcom: serial terminal through cable

exec /usr/X11R6/bin/rxvt -e /usr/local/bin/microcom-serial.snow \

Use microcom

Microcom can be executed directly from lanch pad. It is similar with minicom, but you should first press ~ to setup serial communication speed.

Use VR3 as a Ebook Reader (Chinese supported)


TWReader can read plain text or HTML format books. Chinese is NOT supported yet.

less and w3m (support Chinese)

I plan to make a cramfs rom-disk image which aim to support Chinese I/O. Now I have a preliminary version, which include gbxvt (rxvt with GB2312 support). With less and w3m, you can read GB2312 encoding plain text or HTML formatted ebooks written in simplified Chinese.

You could visit THIS THREAD to download the latest rom-disk image which was named root-1.2.6-gb.cramfs.gz . To upgrade your Agenda VR3 to this rom-disk image:

$gzip -d root-1.2.6-gb.cramfs.gz
$vrflash -s ttyUSB0 -l -R root-1.2.6-gb.cramfs romdisk

If you do not know the usage or meaning of the parameters for vrflash tool, please see the next section for details.

Figure 1. Desktop of Agenda VR3 — With GBxvt, Jrxvt and Microcom.


To test whether it can show Chinese characters correctly, click GBxvt and run:

default$ less gb.txt

gbxvt plus less

You can use UP and DOWN keys on the left side of your PDA to scroll text, type q to exit.

Hardware Hack

Upgrade SDRAM

The original Agenda VR3 have only 8MB SDRAM, it's too small for nowadays. Upgrading its SDRAM to 16MB is not complex, but attention should be paied.


Here is a list:

  • instead of NEC D4564163G5, other 8MB(64M bit) SDRAM chip with 16 bit data bus and 3.3V operation voltage just like HY57V651620B, M12L6416A, TBS6416B4E, 54C365164VBT8 was verified suitable. You can buy such a chip from taobao, or desolder it from a obsolete 32MB ~ 128M SDRAM board.
  • a soldering iron with a diameter 0.5mm tip.
  • solder with 0.3mm diameter.
  • enamelled copper wire with 0.2mm diameter.
  • desoldering wire.
  • a tweezers.
  • a multimeter.
  • datasheet of VR4181.
  • datasheet of SDRAM
  • a Agenda VR3 prepared to die in any time.


Upgrade Firmware

vrflash tool, latest kernel and firmware are available in AGOS.

Update PMON

PMON is VR3's bootloader, just like “lilo” or “grub” for Linux PC. On Linux PC, extract pmon-sdram-16M.binary from pmon-sdram-16M.tar.gz, then use vrflash to download the latest PMON firmware.

$vrflash -l -D -s ttyUSB0 pmon-sdram-16M.binary pmon

you can specify other serial port using -s option, for example, -s ttyS0. -l means capture log. -D means Disable PMON overwrite check.


  1. You should use -D option ONLY for downloading pmon. When downloading kernel or romdisk, -D MUST not be used.
  2. You MUST ensure the downloading procedure not be interrupted, otherwise, pmon maybe corrupt then your VR3 will become a beautiful brick. Fully charged batteries is necessary due to the above reason.
Update Kernel

The original kernel of VR3 is not in gzip format, it stored and run in flash directly. The latest PMON need a compressed kernel, it will decompress the kernel and load it into SDRAM.

$vrflash -s ttyUSB0 -l -R vr3-kernel-8.2-sdram.binary.gz kernel

When PMON and kernel are updated, power on the system, it will boot normally if everything goes well.

Hardware Handy Work

  1. Re-solder the SDRAM on VR3 board, put enough solder in every pin, except PIN 19. images/re-solder.jpg
  2. Solder another D4564163G5 8M SDRAM or equivalant such as HY57V651620B on the old SDRAM chip directly, ensure every correspondent pin connected EXCEPT PIN 19 (/CS, chip select).
  3. Connect the the PIN 19 (/CS, chip select) of the upper SDRAM to the NEC VR4181 CPU's PIN 34 (SDCS1#) by a UEW 0.2mm enamelled copper wire. images/finished.jpg
  4. Check all connections by a multimeter.


We can use mt command of PMON to test the upper 8MB SDRAM.

Follow these steps to login PMON

  1. Connect VR3 to PC through quicksync cable (serial cable).
  2. Run minicom or other terminal emulator on PC, ensure it setup the correct port which VR3 is attached.
  3. hold the reset button of VR3, as soon as the LED flash three times, send any character through serial port(press any key in terminal emulator.)
  4. PMON> will show in your terminal emulator.

To test the upper 8MB SDRAM, run:

Uncompressing blocks ... done.
PMON>mt a0800000 800000

If it says no error, the upgrade is successful and you have a 16MB SDRAM to use. Otherwise you should check open circuit and short circuit by a multimeter carefully.

Restore Default

If you detached LCD and touch panel when you solder the new SDRAM, you MUST restore VR3 to default to enable touch panel AFTER the LCD and mother board were assembled together.

login PMON and run command:

Uncompressing blocks ... done.
PMON>$linux console=ttyS0,115200 init=/sbin/restore_defaults

Then restart system, free command will report approximate 13MB RAM because the kernel will occupy the rest.

Programming VR3

With cross compiler and other tools, VR3 may also be used as a Development Board for embedded programming.

Developer Home of Agenda Wiki offered a lots of resources.


To be continued.