MIOS-Programming over Sysex ... :o(

Testing/Troubleshooting
1

I couldn´t get MIOS on my PIC. The bootstrp loader does send requests but doesnt send any Checksums over MIDI while receiving Sysex.

I have the problem, that the LED on the RX pin istn´t flickering. It is on one lighting level, no matter if MIDI comes or not. Is the optocoupler maybe defect?

I tried out everything, that´s described in the other threads… in addition with the gameport an w/o opto-chip.

Perhaps there is something wrong with the ID? I tried to program the bootstrap ID 000000000000 two times.

2

Did you also try the MIDI In/Out ports of your PC?

Best Regards, Thorsten.

P.S.: the MIDI troubleshooting guide has been updated: http://www.ucapps.de/howto_debug_midi.html

3

Hi Thorsten,

thanks for that great debug-sheet!!! What´s exactly to measure at RA4 ? The resistor should be 1k instead of 10k. My core voltage is 5.09 V and at RA4 i do have 0.1V.

The LED on RX pin lits, but doesn´t flicker when receiving a sysex-stream. The voltages on the 138 are ok. how about checking the optocoupler by connecting 5V/0V over 220Ohm to the input?

Also the 1:1 connection to the gameport doesn´t solve the problem.

I think it is perhaps a wrong mios/bootstrap combination? I downloaded bootstrap 1.1b and mios 1.4, wrote the bootstrap with ID 0 to the pic. When sending the sysex to the pic, he doesnt react. my midi interface is good, too (send/rec-sysex).  ???

Is there another possibility to check midi-in, perhaps i can upload a tool via jdm?

in addition: midiox says with the input “port” is sometimes — and sometimes xxx

one more: i´ve soldered the 10mhz osc inside the pic-socket, but this shouldn´t make any problems.

4

Hi,

> thanks for that great debug-sheet!!!

I hope that it will provide so much checks in the future that everybody

will be able to locate the errors w/o searching in the forum for hints :slight_smile:

> What´s exactly to measure at RA4 ? The resistor should be 1k

> instead of 10k. My core voltage is 5.09 V and at RA4 i

> do have 0.1V.

You are right, this was an error in the schematic. The voltage level

at RA4 isn’t for interest. Although it’s nice to know that it’s 0V,

this means that the bootstrap loader has switched on the output

driver (and therefore: that the PIC is running).

> The LED on RX pin lits, but doesn´t flicker when receiving

> a sysex-stream. The voltages on the 138 are ok. how about

> checking the optocoupler by connecting 5V/0V over 220Ohm

> to the input?

a good idea! I’ve added a new item to the list

Is this test working: http://www.ucapps.de/mbhp/mbhp_core_midiin_debug2.gif

If it does, there must be a problem with the optocoupler

> Also the 1:1 connection to the gameport doesn´t solve the problem.

Could be a driver problem - the gameport of my old mainboard

also never worked under Windows, but only under Linux… :wink:

> I think it is perhaps a wrong mios/bootstrap combination?

No, the bootstrap loader works independent from MIOS

> I downloaded bootstrap 1.1b and mios 1.4, wrote the bootstrap

> with ID 0 to the pic.

And you receive “F0 00 00 7E 40 00 01 F7” which indicates

that the device ID is set correctly

(with another device ID, for example 0x42, you would

receive F0 00 00 7E 40 42 01 F7)

> When sending the sysex to the pic, he doesnt react. my midi

> interface is good, too (send/rec-sysex).  ???

Now you will find another new item which demonstrates how

to loopback MIDI w/o PIC. This helps you to ensure that

the hardware itself is working ok

> Is there another possibility to check midi-in, perhaps i can upload

> a tool via jdm?

this would be more complicated and fault-prone than using

the boostrap loader

> in addition: midiox says with the input “port” is sometimes

> — and sometimes xxx

I know this effect, must be an imperfection in MIDI-Ox

> one more: i´ve soldered the 10mhz osc inside the pic-socket,

> but this shouldn´t make any problems.

Your bootstrap loaders sends a proper request, so the PIC

is running fine.

So, check out the two new tests under

http://www.ucapps.de/howto_debug_midi.html

Best Regards, Thorsten.

5

Hi Thorsten,

your debug sheet is much better now!!  ;) But it doesnt solve my problem.  :-[ At the moment I have the core module w/o the optocoupler and direct connection to the gameport everything is working fine, but i´m not able to upload mios. i checked everything a few times. midi is present at the RX pin (Led is flickering), bootstrap sends the request, all votages are ok.  hardware-loopback with the gamport works fine, too.

next step: i pulled out the pic and connect the two socket-pins (RX/TX) together. now it comes –> with power (1.2k to 5V), the loopback isnt working. when switching off the board-power, the loopback works. so i diconnect the 1.2k (what is it for??). after inserting the pic there was a change in behaviour: when beginning the sysex, the pic stops to send requests, but thats it. after a reboot he continues…  :o

tomorrow i will buy a new optocoupler to see, if the old one is really defect, or there is something wrong with the pullup 1.2k in the input path…??

6

Hi,

the 1.2k resistor is used to pull-up the open drain output of the 6N138. It’s strange that the circuit works w/o power, because the optocoupler should electrically isolate the core module from the MIDI Out of your computer - the only possible current source.

Did you mount the 6N138 in the right direction?

Did you remove the 6N138 when working with the gameport?

Best Regards, Thorsten.

7

oh, i do not have it int the circuit at the moment. the thing with the pullup is w/o the 138. i´m only working with the gameport for troubleshooting

8

What happens when you send following SysEx message to the core?

F0 00 00 7E 40 00 02 20 00 00 01 01 02 03 04 05 06 07 08 09 0a 0b F7

It should return:

F0 00 00 7E 40 00 0E 03 28 ...

Note: if the bootstrap loader doesn’t reboot periodically, you must send the dump within the first 2 seconds after power-on!

Best Regards, Thorsten.

9

the bootstrap boots periodically.

there is no reaction to the sysex-message, when i send it.

:-[

is it possible, that the bootstrap is burned in a wrong way? but the verification in the burner says, that it is everything ok.

10

is it possible, that the bootstrap is burned in a wrong way? but the verification in the burner says, that it is everything ok.

everything is possible, thats the problem… :wink:

You could try to burn the .hex file of MIOS directly into the PIC.

This step isn’t recommented under normal circumstances (since the first level bootstrap loader is essential), but it could help you to debug the MIDI IO

With MIOS only the upload request won’t appear anymore after startup, but you will be able to send various requests to the second level BSL: http://www.ucapps.de/mios/mios_sysex_implementation.txt

With

F0 00 00 7E 40 00 0D 01 00 58 28 00 01 00 00 00 00 00 00 F7

the MIDI merger will be enabled - thereafter every incoming MIDI event should be echoed.

Best Regards, Thorsten.

11

Hi Thorsten,

i´ve burned mios directly. After sending the sysex to enable the merger, the pic gives the sysex back, that this is a wrong debug command (0E 07 02). So I think MIDI is working, because the pic replyes something, but it seems to be another problem… why doesnt he understand this command?

12

Well, to finish this thread:

After measuring everything, I found out, that my Gameport isn´t working very well. So I checked the 6N318 once more and bought a new one. Because it doesnt work better, I experimented with the 5k6 and 1k2 resistors. I changed the 5k6 into a 10k and voilá: My MIDI-Input works!!!  ;D ;D ;D

So take care about your MIDI-Interface. It seems that they do have many differences in quality. My german EES-Interface is working fine since over 10 years, so there must be something with the hardware on my core-module …  ;)

Best Regards,

The Accelerator

13

Perfect!!! :slight_smile:

It shows shows again, that gameports are not reliable on every PC. Maybe I should highlight this in the interconnection diagram.

Concerning the 5.6k resistor: I’m not sure about its function, it was a suggestion made by an experienced guy - I guess that it controls the bias level between the two integrated transistors - on the other hand: in the datasheet it’s left open…

could you please check if your MIDI In still works without R5?

Best Regards, Thorsten.

14

I´ve checked it –> there must be an resistor !! It´s not working w/o one.

regs

15

Thanks - thats useful to know! Could you please do an additional test: connect a 1k (or 470 Ohm) resistor in parallel to the 1.2k resistor (so that the resulting resistance is about 330 Ohm) and try it without the 10k - does this work?

Best Regards, Thorsten.