Hardware Hacking - Serial Port Success

[BobTheBuilder]

Okay - the hardware section isn't really for "Hardware Mods" - so I'll start this thread here - the mod can cut 'n' prune it to a more suitable place if necessary.

A while back I asked if anyone had noticed that there appears to be the solder pads for a serial port - no-one answered - and we managed to get a kernel booted without having to resort to hooking it up.

Anyway - I actually got around to working out the missing components

You need:-
1x MAX562CAI
Some capacitors ( I used 0.68uF for the large layout caps , and 0.33uF for the smaller ones ).


Here's the first fews lines sent out by the box ( 9600,8,n,1 )

loaded at:     00500000 005A11F8
relocated to:  00400000 004A11F8
board data at: 0049E128 0049E168
relocated to:  0040555C 0040559C
zimage at:     00405B50 0049D919
avail ram:     004A2000 01000000

Linux/PPC load: console=ttyS0,9600 profile=3 root=/dev/nfs
Uncompressing Linux...done.
Now booting the kernel
Linux version 2.4.17_mvl21-vdongle (mvp@Svarog) (gcc version 2.95.3 20010315 (release)) #247 Mon Dec 22 14:56:29 GMT 2003
IBM Redwood6 (STBx25XX) Platform
Port by MontaVista Software, Inc. (source@mvista.com)
On node 0 totalpages: 4096
zone(0): 4096 pages.
zone(1): 0 pages.
zone(2): 0 pages.
Kernel command line: console=ttyS0,9600 profile=3 root=/dev/nfs
Console: colour dummy device 80x25
Calibrating delay loop... 251.49 BogoMIPS
Memory: 13920k available (1120k kernel code, 428k data, 72k init, 0k highmem)
Dentry-cache hash table entries: 2048 (order: 2, 16384 bytes)
Inode-cache hash table entries: 1024 (order: 1, 8192 bytes)
Mount-cache hash table entries: 512 (order: 0, 4096 bytes)
Buffer-cache hash table entries: 1024 (order: 0, 4096 bytes)
Page-cache hash table entries: 4096 (order: 2, 16384 bytes)


Now - who fancies hooking up that compact flash reader ????

And who has any ideas about the "other" chip ?? ( USB ? )

BtB.

[BobTheBuilder]

I should of course add

THIS IS ONLY FOR THE VERY EXPERIENCED HARDWARE HACKERS !!!!

:-)

[BobTheBuilder]

Ooooh - interesting ....

Found a bootloader

                  local=0.0.0.0  remote=255.255.255.255  hwaddr=000dfe0xxxxx
 ----------------------------
Update Flash  : Disabled
Automatic Boot: Enabled
 ----------------------------
  1 - Toggle Power-On Tests
  2 - Change a Boot Device
  3 - Change IP Addresses
  4 - Ping test
  5 - Change Baud Rate for S1 Boot
  6 - Toggle Update Flash
  7 - Toggle Automatic Boot
  B - Bootlogo Management
  D - Display Configuration
  S - Save Changes
  I - Toggle I-Cache
  L - Dump Registers
  T - Test SDRAM BANK0,1
  C - Checksum Flash
  H - Haup Debug Boot Enable
  Z - Set Ethernet HW Address
  0 - Exit Menu and Boot Application
->


BtB.

[jon]

So I certainly am not an experienced hardware hacker, but I certainly would love to have a serial port on my mediamvp.  Figuring out how the hardware works would be infinately easier with xmon and kgdb.

So, how about some more information on what to do with the parts you describe?  I promise I won't hold you liable if I fry my box.  :)

Jon

[dgage]

Jon,

If you do fry your box, I will Paypal you $20 to help you get a new one as a way of saying thanks for all your work on mvplay et al.  I know it's not much but every little bit helps.  If I new Linux and C better, I might actually be able to help but alas...

David

[BobTheBuilder]

So I certainly am not an experienced hardware hacker, but I certainly would love to have a serial port on my mediamvp.  Figuring out how the hardware works would be infinately easier with xmon and kgdb.

So, how about some more information on what to do with the parts you describe?  I promise I won't hold you liable if I fry my box.  :)

Jon

U14 is the MAX562CAI  ( I got some samples from Maxim ).
The (7?) capacitors around U14 aren't critical - so I got the nearest values that fitted the datasheet / pcb.
The MAX562CAI is just a level convertor ( converts the 3.3v levels from the STB02500 to +/- 5v of the serial port.

If you haven't soldered such surface mount components before - I would strongly suggest you get someone to do it for you - or practice before doing it.

If you're in the UK - I ordered the capacitors from Farnell.
422-7104  - 0.33uF
333-0242  - 0.68uF

Of course - it's likely these aren't the exact parts intended - but they do appear to work okay.
( The range of options from Farnell didn't allow me to pick exactly what I would have liked ).

Anyway - I have to go off and do some paid work for a few days - I'll try and post some pictures / parts lists at the weekend.

BtB.

[arghgra]

Ooooh - interesting ....

Found a bootloader

                  local=0.0.0.0  remote=255.255.255.255  hwaddr=000dfe0xxxxx
 ----------------------------
Update Flash  : Disabled
Automatic Boot: Enabled
 ----------------------------
  1 - Toggle Power-On Tests
  2 - Change a Boot Device
  3 - Change IP Addresses
  4 - Ping test
  5 - Change Baud Rate for S1 Boot
  6 - Toggle Update Flash
  7 - Toggle Automatic Boot
  B - Bootlogo Management
  D - Display Configuration
  S - Save Changes
  I - Toggle I-Cache
  L - Dump Registers
  T - Test SDRAM BANK0,1
  C - Checksum Flash
  H - Haup Debug Boot Enable
  Z - Set Ethernet HW Address
  0 - Exit Menu and Boot Application
->


BtB.

Hi Bob,

very good Job! :)

Two questions:
- How did you "activate" the bootloader?
- Why did you use the MAX562? Or: Is is possible to use
another IC in a more user-friendly package (DIP,...)?

best regards,
Reiner

[BobTheBuilder]

very good Job! :)

Two questions:
- How did you "activate" the bootloader?
- Why did you use the MAX562? Or: Is is possible to use
another IC in a more user-friendly package (DIP,...)?

best regards,
Reiner

1. Thanks.
2. I think I kept pressing enter / then applying power.
3. Because that was the pad layout / size on the PCB - and I wanted a neat solution - rather than have an external level convertor - so If you wish to use DIP - you can - but it'll obviously have to be on an external PCB.

BtB.

[BobTheBuilder]

Ahh - maybe I'll put this in the correct place

Okay - I've taken a picture - and uploaded it - SHS will hopefully make it available soon.

The big caps are 0.68uF , the small 0.33uF

The black wire is GND ( pin 5 of a DB9 female ).
The Red Wire is pin 3 of the DB9
The Yellow wire is pin 2 of the DB9.

Other signals may be implemented - but I haven't looked.

BtB.

[SHS]

[LikeHardwareHackn]

Okay - the hardware section isn't really for "Hardware Mods" - so I'll start this thread here - the mod can cut 'n' prune it to a more suitable place if necessary.

BtB.

Great work!, Bob, I have another hardware question for you (hum, perhaps I should start a new thread).  Have you been able to find the TOSLINK (a.k.a. SPDIF)output on the PowerPC?  Getting access to this would turn me from a spectator to a MediaMVP user.

[BobTheBuilder]

Okay - the hardware section isn't really for "Hardware Mods" - so I'll start this thread here - the mod can cut 'n' prune it to a more suitable place if necessary.

BtB.

Great work!, Bob, I have another hardware question for you (hum, perhaps I should start a new thread).  Have you been able to find the TOSLINK (a.k.a. SPDIF)output on the PowerPC?  Getting access to this would turn me from a spectator to a MediaMVP user.

I can't say I've looked ( there is certainly nothing that jumps out as either SPDIF or TOSLINK ) - also it would be unlikely that the software supports it ( we don't have access to the source code for the IBM specific drivers ).

Sorry :-(

BtB.

[keith721]

BobTheBuilder: Were you really guessing or were you looking at the datasheet??

[BobTheBuilder]

Did I ever say I was guessing ?  :)

The only difference between the datasheet and the layout appears to be that C1B isn't used on the MVP - I guessed that meant it was using the on board voltage doubler rather than the tripler.

So - that's the only 'guess' I made.

Of course - I spent a while looking through all the possible datasheets until I found the best match for input / output / capacitors.

BtB.

[keith721]

You said:

If you're in the UK - I ordered the capacitors from Farnell.
422-7104 - 0.33uF
333-0242 - 0.68uF

Of course - it's likely these aren't the exact parts intended - but they do appear to work okay.
( The range of options from Farnell didn't allow me to pick exactly what I would have liked ).

and clearly never used the word "guess".   :oops:

So, the STBx25xx block diagram shows serial[0-3] lines, a Sync serial port, and a Serial controller port all on the OPB bus.  Did you notice any routing of these other signals to the MAX562CAI area on the PCB?