picandies
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compute moduel upgrade (rpi4)

Mon Jun 24, 2019 8:06 pm

When will the compute module get similar rpi4 upgrades (such as more memory, usb3, faster processing)?
They've kinda kept their specs in sync, hope it continues for ease of development.

Andyroo
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Re: compute moduel upgrade (rpi4)

Mon Jun 24, 2019 9:32 pm

Countdown to thread lock started....

The Foundation or Trading teams never announce products before they are available and they do not speculate that some will ever be made.

Looking at tonight’s availability you could claim the Pi 4 has been announced before its available :lol: :roll: :lol:
Need Pi spray - these things are breeding in my house...

John Westlake
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Re: compute moduel upgrade (rpi4)

Mon Jun 24, 2019 11:30 pm

Beat me to the post :)

With the launch of the new RPi4B I guess it can only be expected that "we" here on the CM section of the forum would be asking for for a CM4 :)

I'm sure the issue faced by RPi is wither or not to move away from the CM1/CM3 Compatible pin arrangement - and I personally I believe it would be "Flogging a dead horse" trying to maintain backwards compatibility.

I'd like to suggest calling the module "CM Pro" - as working with PCI Express Gen 2 4Gbps and RGMII Bus requires "professional level" design skills, sure it can be designed by a competent DIY'er - but its not your typical EE DIY skill level....

If I maybe so bold as to suggest a Spec, (It be interesting to see how close this would be to any internal plans) :)

1. PCI Express Gen 2 (4 lines at 4Gbps) - USB ports etc can be added with the use of the VLI PCI Express to USB Bridge as on the RPi4B

2. Dual HDMI

3. RGMII Bus (Ethernet PHY Bus)

4. LVDS for internal display (If the BCM2711 features an LVDS display interface), LVDS Deserialisers are cheap and simple to use to convert to a parallel RGB LCD interface if required) - easy to provided an application note...

5. WiFi Bus (SDIO)???

6. I2C / I2S / GPIO's on the remaining pins...

7. eMMC Memory / SDCard interface

8. For Pro users just offer the 4GB version...

9. I'm guessing an dedicated OTG USB port is also required for bootloading etc?

Personally for our applications, It would be great to have a pin that allows injection locking of the onboard SoC Clock (allowing an external Clock to synchronize the onboard Pierce oscillator for EMC critical applications) - just a input Pin on the module with a small value capacitor (say 1pF) connected to the Xin pin of the existing SoC pierce oscillator circuit. (I understand this is a rather unique usage case).

Its a shame that the MXL7704 does not offer external synchronization :(

xirvin
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Re: compute moduel upgrade (rpi4)

Thu Jun 27, 2019 3:00 am

i doubt getting an upgraded cm4 without fixing the supply chain problem /availability for the CM3+ will do any good for raspberry foundation. Im so frustrated getting ahold of a cm3+ /32gb raspberry pi.

aBUGSworstnightmare
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Re: compute moduel upgrade (rpi4)

Thu Jun 27, 2019 9:30 am

When speaking about LVDS ... Keep in mind we talk about a lot of pins (single channel LVDS is 10pins already).
We have a 4 lane MIPI DSI which should be avaialble for connecting displays to (not speaking of the official one). If one needs other interface as MIPI you can use a MIPI to what's needed bridge.

John Westlake
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Re: compute moduel upgrade (rpi4)

Thu Jun 27, 2019 12:45 pm

I understand that MIPI is a closed interface, legally you are required to be a licensed member of the MIPI consortium - there is no way we could afford these costs.

RPI have been less then forthcoming about working with the MIPI interface, I can understand why, but its rather frustrating and not professional, they are trying to offer a platform to professional users, but then are so protective over such important information.

"10 lines" of LVDS is a God send when compared to the full fat 24bit RGB bus!

Due to the legal issues with implementing MIPI for use smaller users, LVDS is a nice simple solution.
Last edited by John Westlake on Thu Jun 27, 2019 1:04 pm, edited 1 time in total.

John Westlake
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Re: compute moduel upgrade (rpi4)

Thu Jun 27, 2019 1:00 pm

xirvin wrote:
Thu Jun 27, 2019 3:00 am
i doubt getting an upgraded cm4 without fixing the supply chain problem /availability for the CM3+ will do any good for raspberry foundation. Im so frustrated getting ahold of a cm3+ /32gb raspberry pi.

I agree that there always seems to be supply issues with CM3 etc. whenever we try to purchase - I could understand this in the early days, but its getting rather long in the tooth so many months later!

Rather upsetting is the apparent non appreciative attitude of the issue by RPi... the typical answer is to speak with RS or Farnell which would be great if they HAD any in stock and not typical "238pcs arriving in 4 months" or some such...

We have 1 year drop shipment arrange, but this requires advance commitment - and times are hard trying to project future sales so far in advanced.... While RPI can be more or less assured of selling whatever can manufactured!

IMO we give Rpi a lot of leeway with regards to poor documentation and poor sales support (how many times has it been asked with help adding WiFI IC's to the SDIO bus) etc. It be good to see RPi get more serious WRT supporting its Pro users if they feel its an important part of their business model going forward.

It be great if RPi considered creating Applications Notes on typical requirements (such as working with the MiPI, SDIO / WiFI interfaces etc).

jamesh
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Re: compute moduel upgrade (rpi4)

Thu Jun 27, 2019 1:16 pm

John Westlake wrote:
Thu Jun 27, 2019 1:00 pm
xirvin wrote:
Thu Jun 27, 2019 3:00 am
i doubt getting an upgraded cm4 without fixing the supply chain problem /availability for the CM3+ will do any good for raspberry foundation. Im so frustrated getting ahold of a cm3+ /32gb raspberry pi.

I agree that there always seems to be supply issues with CM3 etc. whenever we try to purchase - I could understand this in the early days, but its getting rather long in the tooth so many months later!

Rather upsetting is the apparent non appreciative attitude of the issue by RPi... the typical answer is to speak with RS or Farnell which would be great if they HAD any in stock and not typical "238pcs arriving in 4 months" or some such...

We have 1 year drop shipment arrange, but this requires advance commitment - and times are hard trying to project future sales so far in advanced.... While RPI can be more or less assured of selling whatever can manufactured!

IMO we give Rpi a lot of leeway with regards to poor documentation and poor sales support (how many times has it been asked with help adding WiFI IC's to the SDIO bus) etc. It be good to see RPi get more serious WRT supporting its Pro users if they feel its an important part of their business model going forward.

It be great if RPi considered creating Applications Notes on typical requirements (such as working with the MiPI, SDIO / WiFI interfaces etc).
We don't make the CM or CM3, RS/farnell do, under licence, so they are ACTUALLY the people you need to talk to. However, we do have some influence in where they apply their production capacity, but obviously right now the Pi4 is taking up all production space.

We currently simply do not have the staff to do the other stuff you mention. It would be good if we have people who could help with writing app notes, or direct customer support, but we don't. I do not have any influence on staff numbers, before you ask.
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rpdom
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Re: compute moduel upgrade (rpi4)

Thu Jun 27, 2019 1:20 pm

John Westlake wrote:
Thu Jun 27, 2019 1:00 pm
I agree that there always seems to be supply issues with CM3 etc. whenever we try to purchase - I could understand this in the early days, but its getting rather long in the tooth so many months later!

Rather upsetting is the apparent non appreciative attitude of the issue by RPi... the typical answer is to speak with RS or Farnell which would be great if they HAD any in stock and not typical "238pcs arriving in 4 months" or some such...
It is RS and Farnell who order the production of the units from the Sony factory under licence. RPT and RPF have very little control over that side of things. Hence "Speak to the people who manage it".

John Westlake
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Re: compute moduel upgrade (rpi4)

Thu Jun 27, 2019 1:58 pm

jamesh wrote:
Thu Jun 27, 2019 1:16 pm

We don't make the CM or CM3, RS/farnell do, under licence, so they are ACTUALLY the people you need to talk to. However, we do have some influence in where they apply their production capacity, but obviously right now the Pi4 is taking up all production space.
Hi James, yes i appreciate this, but here must become a stage where RPi needs to take some control back as its been going on now for too long and does not seem to be improving, maybe the Pro side needs to be split off with a different structure. it would not be an issue if RS / Farnell offered the support - but they are being very amateurish about it all.

Farnell's Chinese manufacturer is located just around the corner from our China complex in Baoan SZ and I've literally bumped into guys on the street from the UK supporting RPI production and I know they can support greater capacity if they had the orders so apparently its not a capacity issue, its just the production forecast from the UK.

IMO its time for RPi to come down with its licensees and get this in order... Maybe there is a component supply issue, but I've not heard of anything such thing from China - and I deal with such matters on a a daily basis....
jamesh wrote:
Thu Jun 27, 2019 1:16 pm
We currently simply do not have the staff to do the other stuff you mention. It would be good if we have people who could help with writing app notes, or direct customer support, but we don't. I do not have any influence on staff numbers, before you ask.
I'm working with a company here in the Czech Rep (= affordable by European standards) who have a skilled team of developers and I they could support you here... there is a very large concentration of Linux / Hardware guys in the area due to RedHat and NXP (IMX developers) development centers being based locally... I know this would be an internal discussion, but I could really see this as a possible route to expanding the RPi Pro side....

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Re: compute moduel upgrade (rpi4)

Thu Jun 27, 2019 2:12 pm

John Westlake wrote:
Thu Jun 27, 2019 12:45 pm
I understand that MIPI is a closed interface, legally you are required to be a licensed member of the MIPI consortium - there is no way we could afford these costs.

RPI have been less then forthcoming about working with the MIPI interface, I can understand why, but its rather frustrating and not professional, they are trying to offer a platform to professional users, but then are so protective over such important information.

"10 lines" of LVDS is a God send when compared to the full fat 24bit RGB bus!

Due to the legal issues with implementing MIPI for use smaller users, LVDS is a nice simple solution.
Having the full spec requires being a MIPI member, but using it doesn't.

As aBUGSworstnightmare has said, there are oodles of bridge chips around that will convert for you, generally without having to get involved with the protocol level of MIPI. https://toshiba.semicon-storage.com/us/ ... ridge.html for DSI to DPI, LVDS and embedded DP, and TI also do a bundle of DSI to LVDS (SN65DSI84 and SN65DSI85).
There is a description at https://github.com/anholt/linux/wiki/Ra ... lay-panels for how to add DSI panels. There are drivers in mainline kernel for several bridge chips.

We may not have spelt it out for you, but there is a fair amount of information available should you wish to use it. The simple answer is that it is a fairly niche use case, and hasn't been a major focus for our efforts.
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aBUGSworstnightmare
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Re: compute moduel upgrade (rpi4)

Fri Jun 28, 2019 4:18 am

John Westlake wrote: I understand that MIPI is a closed interface, legally you are required to be a licensed member of the MIPI consortium - there is no way we could afford these costs.

RPI have been less then forthcoming about working with the MIPI interface, I can understand why, but its rather frustrating and not professional, they are trying to offer a platform to professional users, but then are so protective over such important information.

"10 lines" of LVDS is a God send when compared to the full fat 24bit RGB bus!

Due to the legal issues with implementing MIPI for use smaller users, LVDS is a nice simple solution.
well, from my POV Mipi is way beyond the capability of the 'average DIY guy/girl'. MiPI interface is used typically in phones, tablets and small notebooks, which makes it difficult to get hands on the documentation.But documentation is a must as you need to know the power-on/start sequence to light-up the module.

In adddition, operating temp range of MIPI displays might be a problem for use in IA.
John, I agree with you that LVDS would be nice (but from my POV it would require dual channel) as it's still the standard in IA (eDP is further growing). But .. I have some big doubts that it is available on the SOC.
Anyhow, as long as we don't know if there will be a CM4 and which 'standard' it will follow everything is speculative.

W. H. Heydt
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Re: compute moduel upgrade (rpi4)

Fri Jun 28, 2019 6:31 pm

John Westlake wrote:
Mon Jun 24, 2019 11:30 pm
If I maybe so bold as to suggest a Spec, (It be interesting to see how close this would be to any internal plans) :)

1. PCI Express Gen 2 (4 lines at 4Gbps) - USB ports etc can be added with the use of the VLI PCI Express to USB Bridge as on the RPi4B
This would require a whole new SoC, one that is not in use even on the Pi4B, so really not possible before the Pi5B...if then.
2. Dual HDMI
Available on the Pi4B, so to be expected on a CM4.
3. RGMII Bus (Ethernet PHY Bus)
I don't know if that is the exact tech on the Pi4B SoC, but it does have on-board PHY that feeds the GbE connection, so (effectively) present on the Pi4B and therefore to be expected on a CM4.
6. I2C / I2S / GPIO's on the remaining pins...
As I undertand it, there are multiple I2C and I2S busses available on the GPIO pins of the Pi4B, so expect that on a CM4.
7. eMMC Memory / SDCard interface
Present on the CM, CM3, and CM3+ so one would expect it on a CM4.
8. For Pro users just offer the 4GB version...
One kind of wonders what an embedded system would *do* with 4GB, but since there is a 4GB Pi4B, one would expect a 4GB CM4. More interesting is that it has been mentioned that the Pi4B SoC memory controller has 35 address lines, which implies that--in theory--one could have 32GB of RAM. I doubt such a beast would be a practical product, but there is always the Element 14 custom Pi route...
9. I'm guessing an dedicated OTG USB port is also required for bootloading etc?
You mean the way that the "legacy" USB 2 port on the Pi4B SoC--which is connected to the USB-C power connector--is available as an OTG port? And on a CM4 one needn't make that the power connector?

Looks like most of your wish list is within the capabilities of the SoC used on the Pi4B. Now you just have to wait for Pi4B production to catch up with demand, the RPT have time to work out how to package everything for a CM4, get said CM4 design(s) into production, and launch it. I'd give them 18 months or so. 24 months wouldn't surprise me.

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