Solder Pads. How Many And What Can They Do?

[WizardStan]

Actually... I don't see why not, provided the rumbler doesn't draw more than 160ma. Instead of brightness, you get... rumbness?
Unfortunately, the smallest DC motors I can find draw upwards of 400ma. I can't find anything at 160, so maybe that's not such a good idea after all.

 

[thoughtcriminal]

Why would you want a larger internal flash memory anyway? That's what SD cards are for

why not?
I want a large drive within the unit to run the OS and all my applications off. 256 mb isn't going to cut it, I'm thinking more along the lines of 8gb. I'd just feel better using an internal hardwired memory to run such things. I know its built as a gaming platform, but I plan on using it as an all purpose UMPC and media player as well. Besides, I'm going to have at least one SD card slot filled at all times for my music library and the other one filled 90+% of the time for games and other media.

 

[cosam]

There have been many changes since previous discussions.

Any chance of some pictures of the latest PCB?

RS-232 would only be available through an external converter, but the 2.8V supply is there to make it self powered.

Not that I'm adverse to hacking a converter up myself, but are there plans to manufacture an "official" converter/cable?

 

[Squidge]

I want a large drive within the unit to run the OS and all my applications off. 256 mb isn't going to cut it, I'm thinking more along the lines of 8gb. I'd just feel better using an internal hardwired memory to run such

Hopefully by the end of this year, there will be 64GB SDHC cards around, then you can have 128GB of storage at your disposal. Hopefully that'll be enough for most people. Until then, I'm afraid your going to have to live with 64GB, as the internal storage size isn't going to change until you fancy hacking a usb key inside the machine.

QUOTE
Not that I'm adverse to hacking a converter up myself, but are there plans to manufacture an "official" converter/cable?


I don't know myself, but probably for most people who stay within Linux, a USB->Serial cable might suffice?

 

[cosam]

QUOTE
Not that I'm adverse to hacking a converter up myself, but are there plans to manufacture an "official" converter/cable?

I don't know myself, but probably for most people who stay within Linux, a USB->Serial cable might suffice?

I'll probably end up doing that for most things (I think the Pandora would make a great portable serial terminal, for example) but a proper serial console would be most useful for development stuff.

 

[azmodean]

RS-232 would only be available through an external converter, but the 2.8V supply is there to make it self powered.

But IR transmitters/receivers expect the parameters supplied by this port, so a "remote control" mod would be pretty straightfoward from what I understand, thanks for keeping the pads so big, I'm new to hardware mods

 

[Squidge]

Don't forget that for IR, you need an appropriate carrier for the data (eg. 38Khz). You can just throw data out of the port and expect to work, unless that is done in a seperate module.

 

[thoughtcriminal]

I want a large drive within the unit to run the OS and all my applications off. 256 mb isn't going to cut it, I'm thinking more along the lines of 8gb. I'd just feel better using an internal hardwired memory to run such

Hopefully by the end of this year, there will be 64GB SDHC cards around, then you can have 128GB of storage at your disposal. Hopefully that'll be enough for most people. Until then, I'm afraid your going to have to live with 64GB, as the internal storage size isn't going to change until you fancy hacking a usb key inside the machine.


Actually, that's exactly along the lines I was thinking, putting the guts of a usb drive or an SD card internally. I'm not asking the design be changed, I just wanted to know if its got the connections to put one in. I'm guessing by your reply I can, correct me if I'm wrong

 

[Tinnus]

Actually, that's exactly along the lines I was thinking, putting the guts of a usb drive or an SD card internally. I'm not asking the design be changed, I just wanted to know if its got the connections to put one in. I'm guessing by your reply I can, correct me if I'm wrong

You'd use one of the USB ports for that though. Or get a tiny 2-port USB hub and get the guts of all that inside.

Now that I think about it, might be a very interesting mod provided there's enough space

 

[ninjaturtle]

Actually, that's exactly along the lines I was thinking, putting the guts of a usb drive or an SD card internally. I'm not asking the design be changed, I just wanted to know if its got the connections to put one in. I'm guessing by your reply I can, correct me if I'm wrong

You'd use one of the USB ports for that though. Or get a tiny 2-port USB hub and get the guts of all that inside.

Now that I think about it, might be a very interesting mod provided there's enough space

Looks easy enough, might make me want to dig out my solder station and have a crack at it.

 

[Squidge]

If you squeezed a hub in there, you could then connect low speed usb devices directly to the Pandora, rather than being limited to high speed...

 

[ninjaturtle]

If you squeezed a hub in there, you could then connect low speed usb devices directly to the Pandora, rather than being limited to high speed...

You mean by default this only accept high speed usb devices?

USB mod victoms one and two.

Of course I already submitted my order this morning

 

[Jaxartes]

If you squeezed a hub in there, you could then connect low speed usb devices directly to the Pandora, rather than being limited to high speed...

You mean by default this only accept high speed usb devices?

USB mod victoms one and two.

Of course I already submitted my order this morning


The situation wrt USB is more complicated than that, if I recall correctly. Do a search; I know there was discussion about it in the past (I may have even contributed to one such thread). Basically the OMAP chip that's being used in the Pandora has two USB interfaces. One of them acts only as a host, and only for high-speed devices unless you have a hub. The other is an "on the go" port, which means it can switch back and forth between acting like a host and acting like a target. I think the OTG port can handle the lower speeds. It may also have limitations of its own (not putting out much power? I dunno).

 

[EdCa22]

Also, is there a free internal USB port? Otherwise you'd be messing with the socket on the outside...

BTW, if you put software SPI on the external connector you can run an SD card off of it...not sure about the speed though as it's be bit-bashed. Also if the other serial port can be used as GPIO you can put a decoder on there and use those 2 pins as chip selects to run up to 4 extra SD cards off of the EXT connector...

 

[jdh2550]

Also, is there a free internal USB port? Otherwise you'd be messing with the socket on the outside...

AFAIK, there is no free internal USB port. I plan on taking a two port hub (the one that thoughtcriminal bought form New Egg and doing the following:

1) Strip down the hub and remove all the big connectors
2) clip the D+ / D- lines from the board to the existing external port
3) wire the D+ / D- from the board to the upstream port of the two port hub
4) wire the power for the upstream port of the two port hub to the board
5) wire the D+ / D- from one of the downstream ports of the hub to the D+ / D- of the existing external port

Then, I *think* I should have an external port that will handle all USB peripherals and a spare internal port for attaching whatever I can shoe-horn in there.

I've just ordered the 2 port hub $7.99 a great price until you add $6.99 shipping Oh well. I'll strip it down when it arrives but I'm pretty confident that I'll be able to find a place to put it inside the pandora case.

 

[DAP]

Also, is there a free internal USB port? Otherwise you'd be messing with the socket on the outside...

AFAIK, there is no free internal USB port. I plan on taking a two port hub (the one that thoughtcriminal bought form New Egg and doing the following:

1) Strip down the hub and remove all the big connectors
2) clip the D+ / D- lines from the board to the existing external port
3) wire the D+ / D- from the board to the upstream port of the two port hub
4) wire the power for the upstream port of the two port hub to the board
5) wire the D+ / D- from one of the downstream ports of the hub to the D+ / D- of the existing external port

Then, I *think* I should have an external port that will handle all USB peripherals and a spare internal port for attaching whatever I can shoe-horn in there.

I've just ordered the 2 port hub $7.99 a great price until you add $6.99 shipping Oh well. I'll strip it down when it arrives but I'm pretty confident that I'll be able to find a place to put it inside the pandora case.


Just make sure you ordered a powered 2 port hub, or you may have to re-wire some of the pins of the IC to change its configuration. A 2 port hub that thinks it is not self powered (powered by the USB cable alone) will only allow 100 mA or lower devices to be connected.

 

[jdh2550]

Just make sure you ordered a powered 2 port hub, or you may have to re-wire some of the pins of the IC to change its configuration. A 2 port hub that thinks it is not self powered (powered by the USB cable alone) will only allow 100 mA or lower devices to be connected.

In the words of Homer Simpson "Doh!" (that's a self directed "Doh!") I think I got it wrong. Oh well.

 

[Squidge]

Just make sure you ordered a powered 2 port hub, or you may have to re-wire some of the pins of the IC to change its configuration. A 2 port hub that thinks it is not self powered (powered by the USB cable alone) will only allow 100 mA or lower devices to be connected.

Should, not will. There are a lot of hubs out there that don't give a stuff how much you try and suck from them. Typically, current sensing requires additional external electronics to the Hub IC, and many people ignore these requirements to keep cost down, with the result being an out-of-spec "but it works". Most people don't give a stuff if a hub is compliant or not, just that its cheaper, and some manufacturers further confuse people by including a usb2.0 compliant cable and emphasing the "USB 2.0 Compliant" part on there packaging (with the "cable" part in either small letters, or written elsewhere with a microscopic asterix above the "Compliant" word).

 

[DAP]

Just make sure you ordered a powered 2 port hub, or you may have to re-wire some of the pins of the IC to change its configuration. A 2 port hub that thinks it is not self powered (powered by the USB cable alone) will only allow 100 mA or lower devices to be connected.

Should, not will. There are a lot of hubs out there that don't give a stuff how much you try and suck from them. Typically, current sensing requires additional external electronics to the Hub IC, and many people ignore these requirements to keep cost down, with the result being an out-of-spec "but it works". Most people don't give a stuff if a hub is compliant or not, just that its cheaper, and some manufacturers further confuse people by including a usb2.0 compliant cable and emphasing the "USB 2.0 Compliant" part on there packaging (with the "cable" part in either small letters, or written elsewhere with a microscopic asterix above the "Compliant" word).

A USB device is required to tell the master how much current it needs. If the port thinks it is incapable of supplying that much current, the master will shut down the device. At this point current sensing does not even come into play. USB hub chips usually have a handful of configuration pins (quite often doubling as LED status indicators) to tell it how to behave. If it is configured as a 2 port unpowered hub, it will report to the master that its ports max out at 100 mA, even if you bypass its power supply with something beefier. To get this to work, you must also convince the HUB that it is a self powered hub by changing the wiring of those configuration pins so that it will allow devices requesting more than 100 mA to operate.
When you get your hub, find out what IC it is (hope that it is not NEC) and download its data sheet to see which connections need to change.

Where current sensing comes into play is when a device claims that it requires 500 mA (max it can request), but actually uses much more than that. This is where you see "Y" cables with two "A" connectors. Quite often you can get away without the "Y" cable because computers seldom implement the current sensing and power switch that are part of the USB spec.

 

[Squidge]

A USB device is required to tell the master how much current it needs. If the port thinks it is incapable of supplying that much current, the master will shut down the device. At this point current sensing does not even
Yes, I know how it is supposed to work. I'm just saying there are a lot of cheap hubs out there that don't give a stuff how they are supposed to work. For example, I have a £2 4-port host-powered (no seperate power supply possible) hub that I bought from a computer fair. It doesn't care whether or not I connect a device that requests 100mA or well over 500mA. I've even managed to connect a harddisk to it that comes with a Y-cable for power (Obviously the PC doesn't care that it's providing more than 500mA either).