johnthefisherman
Posts: 21
Joined: Mon Jun 12, 2017 11:23 pm

Making a IO board

Wed Nov 15, 2017 9:33 pm

I am building my own CMIO board. But, I need a little help. First off, I do not plan on using very many GPIO's.

What I am trying to accomplish:

1.) More memory. I need at least 16 GB of storage. Also would like to be able to run the regular version of Raspbian.

2.) Use both cameras and displays.

3.) Have 4 USB on it.

4.) Put a Ethernet port on it.

Items 1 and 4 are the real issues for me. I am unable to find and documentation to connect external memory other have a Flash drive through USB. The CM3 lite looks like it needs a micro SD card for its memory. Can i use and EPROM or eMMC that's bigger that 4 GB's? And I don't know where to begin with the Ethernet port.

Looking at the schematics, I can figure out the cameras, displays, and USB's.

Any point in the right direction would be most appreciated.

PhilE
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1417
Joined: Mon Sep 29, 2014 1:07 pm
Location: Cambridge

Re: Making a IO board

Wed Nov 15, 2017 9:40 pm

The BCM283x family of processors can't address more than 1GB of RAM, so item 1) is essentially impossible. The other requirements sounds reasonable, but be careful of running out of memory bandwidth.

User avatar
fruitoftheloom
Posts: 15060
Joined: Tue Mar 25, 2014 12:40 pm
Location: Bognor Regis UK

Re: Making a IO board

Wed Nov 15, 2017 9:41 pm

johnthefisherman wrote:
Wed Nov 15, 2017 9:33 pm
I am building my own CMIO board. But, I need a little help. First off, I do not plan on using very many GPIO's.

What I am trying to accomplish:

1.) More memory. I need at least 16 GB of storage. Also would like to be able to run the regular version of Raspbian.

2.) Use both cameras and displays.

3.) Have 4 USB on it.

4.) Put a Ethernet port on it.

Items 1 and 4 are the real issues for me. I am unable to find and documentation to connect external memory other have a Flash drive through USB. The CM3 lite looks like it needs a micro SD card for its memory. Can i use and EPROM or eMMC that's bigger that 4 GB's? And I don't know where to begin with the Ethernet port.

Looking at the schematics, I can figure out the cameras, displays, and USB's.

Any point in the right direction would be most appreciated.

NeC use the CM3 in TVs which have 16GB eMMC:

https://www.nec-display-solutions.com/p ... ODEL.xhtml
My only "PC" is an Asus ChromeBit running ChromeOS, cloudcentric at its best !
Rockchip Quad-Core RK3288C SoC as used in ASUS Chromebook C201 & Chromebook Flip C100PA as well as the Tinker SBC.
3 Mobile Huawei E5330 Mobile Mi-Fi

User avatar
mahjongg
Forum Moderator
Forum Moderator
Posts: 9660
Joined: Sun Mar 11, 2012 12:19 am
Location: South Holland, The Netherlands

Re: Making a IO board

Thu Nov 16, 2017 12:10 am

PhilE wrote:
Wed Nov 15, 2017 9:40 pm
The BCM283x family of processors can't address more than 1GB of RAM, so item 1) is essentially impossible. The other requirements sounds reasonable, but be careful of running out of memory bandwidth.
storage, not RAM, a PI can essentially use a (nearly) limitless amount of storage.

johnthefisherman
Posts: 21
Joined: Mon Jun 12, 2017 11:23 pm

Re: Making a IO board

Thu Nov 16, 2017 12:35 am

storage, not RAM, a PI can essentially use a (nearly) limitless amount of storage.
So can I increase storage and boot the OS from there?

User avatar
rpdom
Posts: 11818
Joined: Sun May 06, 2012 5:17 am
Location: Essex, UK

Re: Making a IO board

Thu Nov 16, 2017 6:43 am

If you want extra storage you can use the USB, the same as on a Pi 3B. Perhaps get the CM3L and initially put in in a carrier board with an SD card that sets the USB boot OTP bit. Then have USB storage on your own board with whatever capacity you require.

johnthefisherman
Posts: 21
Joined: Mon Jun 12, 2017 11:23 pm

Re: Making a IO board

Thu Nov 16, 2017 5:06 pm

rpdom wrote:
Thu Nov 16, 2017 6:43 am
If you want extra storage you can use the USB, the same as on a Pi 3B. Perhaps get the CM3L and initially put in in a carrier board with an SD card that sets the USB boot OTP bit. Then have USB storage on your own board with whatever capacity you require.
My understanding ins that using a SD card has a slower read and write time that an eMMC. Is that true?

User avatar
rpdom
Posts: 11818
Joined: Sun May 06, 2012 5:17 am
Location: Essex, UK

Re: Making a IO board

Thu Nov 16, 2017 6:30 pm

johnthefisherman wrote:
Thu Nov 16, 2017 5:06 pm
My understanding ins that using a SD card has a slower read and write time that an eMMC. Is that true?
Maybe, but I wasn't suggesting using the SD card for anything other than a one time setting of the boot flag. After that the card will never be needed again. The CM3L will then be able to boot directly from USB (bung an SSD on it if you want speed) without needing the card.

W. H. Heydt
Posts: 7617
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: Making a IO board

Thu Nov 16, 2017 9:00 pm

To clear up what appears to be some confusion...

The CM3 and CM3L have 1GB RAM memory on board. That can't be changed (or exceeded). The CM3 also has 4GB of eMMC flash storage on the board. That's where the OS would be stored to boot from. NEC sells a variant CM3 with 16GB of eMMC flash storage. Last time I checked, the list price of the NEC CM# was $85, but the street price was closer to $65. The CM3L has no on board eMMC but it exposes the bus used for SD or eMMC, so a carrier board can have either an SD slot or eMMC flash, with the quantity of flash storage up to the board designer (i.e How much can you afford?).

Beyond that, there is the Newark/Element14 custom board program. You could have whatever amount of eMMC can be crammed onto the board if your will to pay the up-front engineering costs and buy at least 3K to 5K modules for whatever they want to charge. (That is, by the way, how NEC has the CM3-16 done.)

User avatar
fruitoftheloom
Posts: 15060
Joined: Tue Mar 25, 2014 12:40 pm
Location: Bognor Regis UK

Re: Making a IO board

Thu Nov 16, 2017 9:25 pm

johnthefisherman wrote:
Wed Nov 15, 2017 9:33 pm
I am building my own CMIO board. But, I need a little help. First off, I do not plan on using very many GPIO's.

What I am trying to accomplish:

1.) More memory. I need at least 16 GB of storage. Also would like to be able to run the regular version of Raspbian.

2.) Use both cameras and displays.

3.) Have 4 USB on it.

4.) Put a Ethernet port on it.

Items 1 and 4 are the real issues for me. I am unable to find and documentation to connect external memory other have a Flash drive through USB. The CM3 lite looks like it needs a micro SD card for its memory. Can i use and EPROM or eMMC that's bigger that 4 GB's? And I don't know where to begin with the Ethernet port.

Looking at the schematics, I can figure out the cameras, displays, and USB's.

Any point in the right direction would be most appreciated.

https://store.gumstix.com/gumstix-pi-co ... board.html
My only "PC" is an Asus ChromeBit running ChromeOS, cloudcentric at its best !
Rockchip Quad-Core RK3288C SoC as used in ASUS Chromebook C201 & Chromebook Flip C100PA as well as the Tinker SBC.
3 Mobile Huawei E5330 Mobile Mi-Fi

Return to “Compute Module”

Who is online

Users browsing this forum: No registered users and 2 guests