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Womble

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Joined: 09/07/2020
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Posted: 08:33pm 11 Jul 2020

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Greetings Everyone ...

I am a new forum member, and have just completed my Maximite2 kit

For the benefit of anyone who is also building one of these, here are some notes I made on the process ...

Maximite 2 Kit v3.0 PCB from www.micromite.org (Phil Boyce in the UK)
https://micromite.org/shop/maximites/colour-maximite/colour-maximite-2-kit/
This is the v3.0 PCB with the resistors replaced by Resistor Packs

Only the 100nF Tantalums are polarised, long lead is positive (but do check the markings).
The other capacitors can go either way around.

Capacitor Markings:
10uF = 106+ (polarised Tantalum)
100nF = 104 (can go either way round)
1uF = 105 (can go either way round)

There are THREE values of Resistor Pack. These can be fitted either way round.

Although I did match up the dot markings.
RN7,8,9,10,11,12 = 240R = 6X-2-241LF
RN2,3 = 120R = 6X-2-121LF
RN1 = 120R = 10X-2-121LF

UK Ebay links for the Waveshare and Headers:

Here are the ebay links I used.
Waveshare and Headers (pack of 10) ordered on 24th June 2020.

Headers arrived on 3rd July 2020
eBay item number: 292145372983
https://www.ebay.co.uk/itm/10x-Pitch-2-0-2mm-2x40-Pin-80Pin-Female-Double-Row-Straight-Pin-PCB-Header-Strip/292145372983?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Waveshare arived on 7th July 2020 (because the postman missed me on the 4th)
eBay item number: 153758141729
https://www.ebay.co.uk/itm/Waveshare-STM32H743IIT6-MCU-Core-board-full-IO-expander-JTAG-SWD-debug-interface/153758141729?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

The machine lives

Board fired up yesterday, and case completed today.

I have been hacking around with some of the demo code trying to get a feel for this dialect of Basic.

Still a few teething problems. I'm getting some noise on the video output, which may be down to my monitor, and some interference in the audio playback which seems to be picking up distortion from the video output. However so far I am very pleased with the build.

Many thanks to the Dev Team for an excellent little computer.

Regards

Roy (The Womble)

Womble

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Joined: 09/07/2020
Location: United Kingdom
Posts: 267

Posted: 09:33pm 11 Jul 2020

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Regarding SD Card wierdness ...

On my machine I was having problems with the SD Cards not being detected. Sometimes they worked, sometimes nothing showed up

F1 to open file browser ... may show nothing and an error message is displayed

I am running version CMM2V5.05.03.bin firmware from the CMM2_Construction_Pack.zip

I appreciate that there are newer firmwares out there

I found that setting

OPTION SD TIMING CONSERVATIVE

fixes this on older firmware versions (eg. CMM2V5.05.03.bin)

I am told this is due to be changed on future releases, and will default to this (but called NORMAL)

TassyJim

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Posted: 09:57pm 11 Jul 2020

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It's good to see some images of the V3 motherboard.
You mention polarised capacitors:

Quote Only the 100nF Tantalums are polarised, long lead is positive (but do check the markings).

That should read only 10uF are polarised.

Also,
If you install the latest firmware, it defaults the what was "OPTION SD TIMING CONSERVATIVE" with the alternative option of "FAST" available.
There are other bug fixes so I would recommend using the latest firmware, especially at this early stage of the journey.

Jim

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Womble

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Joined: 09/07/2020
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Posted: 11:05pm 11 Jul 2020

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TassyJim said
That should read only 10uF are polarised.

My bad

, I wrote these notes the day after I built the thing

10uF Tantalums are provided in the kit

TassyJim said
If you install the latest firmware, it defaults the what was "OPTION SD TIMING CONSERVATIVE" with the alternative option of "FAST" available.
There are other bug fixes so I would recommend using the latest firmware, especially at this early stage of the journey.

Many thanks for your comments Jim.

I was thinking of trying a later firmware version tomorrow, I started out with CMM2V5.05.03 simply as a test as it was provided in the construction pack. I am getting some wierd video and audio noise interference, and am planning a more thorough test session tomorrow.

Hang onto your hats boys ... this is going to be a fun ride

abraxas
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Joined: 16/06/2020
Location: Canada
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Posted: 12:37am 12 Jul 2020

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Interesting stuff about your video noise issue. I have a Waveshare based CMM2 that I bought from Circuit Gizmos. It shipped with a 400MHz Waveshare board so I ordered a 480 MHz one to upgrade. I received the second Waveshare board yesterday and experienced video noise issues with it. I tried the latest stable firmware and the latest beta and having the same issue where the 400MHz board gives a clear image but the 480MHz one has noise issues especially with light background. It's actually more like slightly moving horizontal distortion rather than noise but it is consistent and persistent. Looks like CMM2 is not tuned well for the 20% higher clock rate? That or the Waveshare boards are not of very consistent quality.

Womble

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Posts: 267

Posted: 02:16am 12 Jul 2020

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abraxas said Interesting stuff about your video noise issue...
It's actually more like slightly moving horizontal distortion rather than noise but it is consistent and persistent.

This sounds familiar ... My Waveshare is a 480Mhz board.

It appears more in higher resolution modes.

My comments about RF Shielding refer to a video by Neil from Retro Man Cave who found that adhesive copper tape greatly improved video output on a cheap chinese vga converter where the noise was being generated from the RAM bus.

https://www.youtube.com/watch?v=xqlrOcGZx38 Refers

Given that this is a non destructive mod ... I may experiment

There are very many datalines running underneath the Waveshare

Comments from the more electrically savvy forum contributors would be welcone.

I expect the audio noise is caused by similar interference.

For example: This program (which I Wombled for test purposes from this forum) certainly does not include any audio ... but clicks on every frame ...

go figure

Quote
option explicit
option default none
page write 1
const edgelength=100 'set the length of the verticies of the ticosahedron
const zlocation=1000 'how far is the center of the ticosahedron away from us
const viewplane=800 'how far is the viewplane away from us
dim float x,y,d
dim float phi=(1+sqr(5))/2
dim float x1,y1,z1
dim integer col(11), sortorder(11)
dim float q1(4),depth(11),v(4), vout(4)
'
' data for location of verticies for truncated icosahedron of edge length 2
'
data 0,1,3*phi
data 0,1,-3*phi
data 0,-1,3*phi
data 0,-1,-3*phi
data 1,3*phi,0
data 1,-3*phi,0
data -1,3*phi,0
data -1,-3*phi,0
data 3*phi,0,1
data 3*phi,0,-1
data -3*phi,0,1
data -3*phi,0,-1
data 2,(1+2*phi),phi
data 2,(1+2*phi),-phi
data 2,-(1+2*phi),phi
data 2,-(1+2*phi),-phi
data -2,(1+2*phi),phi
data -2,(1+2*phi),-phi
data -2,-(1+2*phi),phi
data -2,-(1+2*phi),-phi
data (1+2*phi),phi,2
data (1+2*phi),phi,-2
data (1+2*phi),-phi,2
data (1+2*phi),-phi,-2
data -(1+2*phi),phi,2
data -(1+2*phi),phi,-2
data -(1+2*phi),-phi,2
data -(1+2*phi),-phi,-2
data phi,2,(1+2*phi)
data phi,2,-(1+2*phi)
data phi,-2,(1+2*phi)
data phi,-2,-(1+2*phi)
data -phi,2,(1+2*phi)
data -phi,2,-(1+2*phi)
data -phi,-2,(1+2*phi)
data -phi,-2,-(1+2*phi)
data 1,(2+phi),2*phi
data 1,(2+phi),-2*phi
data 1,-(2+phi),2*phi
data 1,-(2+phi),-2*phi
data -1,(2+phi),2*phi
data -1,(2+phi),-2*phi
data -1,-(2+phi),2*phi
data -1,-(2+phi),-2*phi
data (2+phi),2*phi,1
data (2+phi),2*phi,-1
data (2+phi),-2*phi,1
data (2+phi),-2*phi,-1
data -(2+phi),2*phi,1
data -(2+phi),2*phi,-1
data -(2+phi),-2*phi,1
data -(2+phi),-2*phi,-1
data 2*phi,1,(2+phi)
data 2*phi,1,-(2+phi)
data 2*phi,-1,(2+phi)
data 2*phi,-1,-(2+phi)
data -2*phi,1,(2+phi)
data -2*phi,1,-(2+phi)
data -2*phi,-1,(2+phi)
data -2*phi,-1,-(2+phi)

dim float ticos(2,59), nticos(3,59)
dim integer i,j,k
dim integer xs(179),ys(179),xe(179),ye(179)
'
' read in the coordinates of the verticies and scale
'
for j=0 to 59
for i=0 to 2
read ticos(i,j)
ticos(i,j)=ticos(i,j)*edgelength/2
next i
next j
'
'Find coordinate pairs that are 100 pixels apart
'
dim integer linelist(2,59)
for i=0 to 59
k=0
for j=0 to 59
d=sqr((ticos(0,j)-ticos(0,i))^2 + (ticos(1,j)-ticos(1,i))^2 + (ticos(2,j)-ticos(2,i))^2 )
if abs(d-100)<1 then
linelist(k,i)=j
k=k+1
endif
next j
next i
'
'convert coordinates to normalised form
'
for i=0 to 59
x1=ticos(0,i): y1=ticos(1,i): z1=ticos(2,i)
create_vector(x1,y1,z1,v())
nticos(0,i)=v(2): nticos(1,i)=v(3): nticos(2,i)=v(4): nticos(3,i)=v(0)
next i
'
'create a quarternion to rotate 2 degrees about a chosen axis
'play with the x,y,z vector which is the sxis of rotation
'
create_normalised_quaternion(2,1,0.5,0.25,q1())

'
' MAIN LOOP
'
do
cls
for i=0 to 59 'rotate coordinates
v(2)=nticos(0,i): v(3)=nticos(1,i): v(4)=nticos(2,i): v(0)=nticos(3,i): v(1)=0
rotate_vector(vout(),v(),q1())
nticos(0,i)=vout(2): nticos(1,i)=vout(3): nticos(2,i)=vout(4): nticos(3,i)=vout(0)
next i

' for every vertex create the lines that radiate from it. This will draw every line twice
j=0
for k=0 to 59
x=nticos(0,k)*viewplane/(nticos(2,k)+zlocation)*nticos(3,k)+MM.HRES/2
y=nticos(1,k)*viewplane/(nticos(2,k)+zlocation)*nticos(3,k)+MM.VRES/2
for i=0 to 2
x1=nticos(0,linelist(i,k))*viewplane/(nticos(2,linelist(i,k))+zlocation)*nticos(3,linelist(i,k))+MM.HRES/2
y1=nticos(1,linelist(i,k))*viewplane/(nticos(2,linelist(i,k))+zlocation)*nticos(3,linelist(i,k))+MM.VRES/2
'store the coordinates for a single line command
xs(j)=x:ys(j)=y:xe(j)=x1:ye(j)=y1:j=j+1
next i
next k
line xs(),ys(),xe(),ye()
page copy 1 to 0,b
IF INKEY$ = CHR$(27) THEN END
loop

'
' SUBRUTINES
'
sub create_normalised_quaternion(theta as float,x as float,y as float,z as float,q() as float)
local float radians = theta/180.0*PI
local float sineterm= sin(radians!/2)
q(1)=cos(radians/2)
q(2)=x* sineterm
q(3)=y* sineterm
q(4)=z* sineterm
q(0)=sqr(q!(1)*q(1) + q(2)*q(2) + q(3)*q(3) + q(4)*q(4)) 'calculate the magnitude
q(1)=q(1)/q(0) 'create a normalised quaternion
q(2)=q(2)/q(0)
q(3)=q(3)/q(0)
q(4)=q(4)/q(0)
q(0)=1
end sub
'
sub invert_quaternion(n() as float,q() as float)
n(0)=q(0)
n(1)=q(1)
n(2)=-q(2)
n(3)=-q(3)
n(4)=-q(4)
end sub
'
sub multiply_quaternion(n() as float,q1() as float,q2() as float)
local float a1=q1(1),a2=q2(1),b1=q1(2),b2=q2(2),c1=q1(3),c2=q2(3),d1=q1(4),d2=q2(4)
n(1)=a1*a2-b1*b2-c1*c2-d1*d2
n(2)=a1*b2+b1*a2+c1*d2-d1*c2
n(3)=a1*c2-b1*d2+c1*a2+d1*b2
n(4)=a1*d2+b1*c2-c1*b2+d1*a2
n(0)=q1(0)*q2(0)
end sub
'
sub create_vector(x as float,y as float ,z as float,v() as float)
v(0)=sqr(x*x + y*y + z*z)
v(1)=0
v(2)=x/v(0)
v(3)=y/v(0)
v(4)=z/v(0)
end sub

sub rotate_vector(vnew() as float,v() as float,q() as float)
local float n(4),iq(4)
multiply_quaternion(n(),q(),v())
invert_quaternion(iq(),q())
multiply_quaternion(vnew(),n(),iq())
end sub

The clicking actually adds to the coolness of this program, but its not supposed to be there. Kudos to the author, this is a cool demo.

Help and comments appreciated as always.

TassyJim

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Joined: 07/08/2011
Location: Australia
Posts: 5882

Posted: 02:20am 12 Jul 2020

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abraxas,
I can't see any video interference with either of my Waveshare boards 400 or 480 MHz.
I do have some RF emissions from the board, especially since I changed to a 8MHz oscillator in place of the crystal.

It is not enough to cause any interference to the audio or video, just audible when listening to my Amateur radios.

I suggest you try a video lead with suppressors fitted.
Likewise, a RF suppressor on the audio and USB leads is a good investment.

Jim

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Womble

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Posted: 02:21am 12 Jul 2020

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abraxas said Interesting stuff about your video noise issue.

Abraxas ... try something with audio ... is the sound output clean, or is there distortion/interference?

I would be interested to hear your experience.

Womble

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Posted: 02:27am 12 Jul 2020

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TassyJim said I suggest you try a video lead with suppressors fitted.
Likewise, a RF suppressor on the audio and USB leads is a good investment.

Already tried that ... ferrite cores on both the audio and vga leads.

I will test with multiple vga displays and cables tomorrow.

Watch this space ...

Womble

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Posted: 02:35am 12 Jul 2020

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BTW ... I'm not knocking an awesome design

I fully expect that my problems are self caused.

Wombles (being a form of stuffed toy) have kapok for brains.

I keep thinking ... what have I done wrong ?
Edited 2020-07-12 12:36 by Womble

GregZone
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Joined: 22/05/2020
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Posted: 02:37am 12 Jul 2020

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Interesting. I didn't even know there was a V3.0 PCB?

Are the resistor packs the only change? Or, are there other updates on the V3.0 PCB?

Personally, I think I prefer the older V2 PCB using 1205 SMD resistors. Although not TH, the 1205's are easy enough to hand solder.
But the resistor packs do look a whole lot better than vertically mounted individual TH resistors!

Definately get onto the latest BETA firmware.

I was also bitten by the SD issue until someone pointed out CONSERVATIVE option.
Much better now that the default is the marghinally slower (but seemingly more compatible) speed, and those wanting to experiment with faster speed can try FAST.

Womble

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Posted: 02:55am 12 Jul 2020

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GregZone said Interesting. I didn't even know there was a V3.0 PCB? �

Are the resistor packs the only change? �Or, are there other updates on the V3.0 PCB?

Personally, I think I prefer the older V2 PCB using 1205 SMD resistors. Although not TH, the 1205's are easy enough to hand solder.
But the resistor packs do look a whole lot better than vertically mounted individual TH resistors!

Definately get onto the latest BETA firmware.

I was also bitten by the SD issue until someone pointed out CONSERVATIVE option.
Much better now that the default is the marghinally slower (but seemingly more compatible) speed, and those wanting to experiment with faster speed can try FAST.

I ordered my kit before it appeared on the webise at micromite.org

For a ham fisted solderer like me the resistor packs are a godsend �

Unsure if there are any other changes ... does not look like any from examining the schematics.

I'm going to install one of the beta firmwares tomorrow, now I have a working MCP2221A

A very nice chap clued me in on the SD issue ... shout out to Phil Boyce (aka WhiteWizzard ... Hope I got that right) I cannot recommend the service received from micromite.org highly enough ... Exemplarary

Edited 2020-07-12 12:57 by Womble

KeepIS

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Posted: 04:32am 12 Jul 2020

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I have no clicking audio running that wire frame ball demo.

Music mp3 files sound fine.

I guess you know that the audio from the DAC is not AC coupled and will not drive low impedance loads, obviously doing that would cause clipping, especially if the volume is wound up.

480MHz waveshare board.

Mike.

It's all too hard.
Mike.

KeepIS

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Posted: 04:55am 12 Jul 2020

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I note that the MB you have has been redesigned to accommodate resistor arrays, therefore the layout of the digital lines is different from the standard WS MB that I'm using, not saying there is anything wrong, it may be better, just a difference.

I know that layout definitely contributes to noise in 800x600 modes. I proved that when I had my WS module wired up with short leads tacked onto the top of the PCB connectors (top of the WS board) as no sockets or MB were available at the time. In that test setup there was a small amount of Horz jitter on mode 1,12. Those leads were short and right away from the CPU, I did a lot of testing and never eliminated it.

When I finally built the Motherboard and with the same WS board, the video was worse with noticeable jitter / tearing now on mode 1,8 and really bad on Mode 1,12 /16. So it followed the R-2R layout. BTW all of the 640 modes are fine.

Mike.

It's all too hard.
Mike.

Poppy

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Posted: 05:08am 12 Jul 2020

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Anyone running the SMD-Version (the one without the Waveshare-Board) having such issues as well ... yet?

Andre ... such a GURU?

Grogster

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Posted: 07:09am 12 Jul 2020

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I have built heaps of the SMD version, all VGA is rock-solid.
Not a problem - for any of my boards, anyway.
I test each and every one I build before shipping them, so I would see any VGA issues during the QC(quality control) test.

Smoke makes things work. When the smoke gets out, it stops!

matherp
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Posted: 07:52am 12 Jul 2020

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Quote Anyone running the SMD-Version (the one without the Waveshare-Board) having such issues as well ... yet?

Quote It's actually more like slightly moving horizontal distortion rather than noise but it is consistent and persistent.

The SMD version uses a crystal oscillator rather than a crystal so will not see the issue. The solution to any video issues is to remove the crystal from the Waveshare and install the optional oscillator and capacitor on the motherboard. You need a 0705 8Mhz oscillator and a 1206 10nF capacitor.

Some (hopefully very few) Waveshare boards have this issue. I do not believe it is related to 400MHz or 480MHz. I can overclock a 400MHz part to 480MHz without any issue. It may be a crystal quality issue or some variance in the load capacitors. The issue is definitely on the Waveshare and not related to whether you are using a V2.1 (upright resistors) or V3.0(resistor pack) motherboard.

austfox
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Posted: 08:19am 12 Jul 2020

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Well I learnt something from this thread. I always thought resistor networks only came with a common pin, hence the reason for the dot on the package. It seems the correct terms to differentiate the two types are bussed and isolated. (There is also a dual terminator type, which is a combination of the two, but this is probably much less common).

austfox
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Posted: 08:26am 12 Jul 2020

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Womble

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Posted: 12:09pm 12 Jul 2020

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Thanks Mike, your comments are appreciated.

KeepIS said I guess you know that the audio from the DAC is not AC coupled and will not drive low impedance loads

I am currently using the audio input built into my monitor, which should be fairly high impedance. The monitor is an IIyama Prolite LCD. I will try some alternative speakers.

KeepIS said When I finally built the Motherboard and with the same WS board, the video was worse with noticeable jitter / tearing now on mode 1,8 and really bad on Mode 1,12 /16. So it followed the R-2R layout. BTW all of the 640 modes are fine.

That sounds like the video problem I am seeing.

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