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Forum Index : Microcontroller and PC projects : Stepper Project
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phil99 Guru  Joined: 11/02/2018 Location: AustraliaPosts: 3222 |
For your testing you may need to change the I2C address from &H50 to something else. Your RTC module probably has a 24C32 EEPROM on it that could also be using that address. At the console type - List System I2C and it will list all the addresses currently in use. The RTC chip will probably be &H68 and the EEPROM will be in the range &H50 to &H57. |
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Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 2002 |
Just tried that list system I2C > list system I2C HEX 0 1 2 3 4 5 6 7 8 9 A B C D E F 00: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: 50 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- 68 -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- > Now the zero is connected along with the RTC Ok silly me had the connections wrong and now they are the right way doing a Run > run ☼ ☼ ☼ ☼ ☼ ☼ ☼ ☼ ☼ ☼ ☼ > Where it shows on the USB connect on figure on the LCD it does show 8 figures Edited 2026-05-14 18:19 by Bryan1 |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 3222 |
&H50 is the address of the EEPROM so change your master / slave code to use say &H55. Or anything except &H50 or &H68. The example code in the manual should be sending all the uppercase letters of the alphabet to the slave one at a time so the slave console should show:- A B C D E etc An the slave should be sending its local Time$ to the master. So master console should show something like:- 00:05:04 00:05:05 00:05:06 00:05:07 etc Edited 2026-05-14 18:34 by phil99 |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 2002 |
For some reason it does seem this computer as when I plug my good C cable the zero doesn't show up on the com port. Now doing a reboot did see it respond and come back with a com port so be right back and see if it does respond. Edited 2026-05-14 18:28 by Bryan1 |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 2002 |
ok did a reboot and still no com port assigned, now the USB for the pico is unattached and the battery is off line so the zero should be seen. Now I just connected that new zero and it got a com port so I tried again and removed the +5V line to the zero as it does power the pico off the usb but still no com port so all that is connected to the zero is the I2C lines and earth. Now just removed the zero from the board and the com port came up and when picking up the zero it was hot on the back so the regulator was nice and hot so I may need to visit a new power supply as it was tied to the 5V rail and I did have a wire going to VSYS. |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 2002 |
Ok got both codes loaded with &H55 and when run nothing on both the console and LCD [CODE> list system I2C HEX 0 1 2 3 4 5 6 7 8 9 A B C D E F 00: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: 50 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- 68 -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- ] Edited 2026-05-14 18:48 by Bryan1 |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 3222 |
Have you put 5V on the 3.3V supply? It might be the Pico chip that is cooking. Nothing there should draw enough current to make the regulator hot, except a short somewhere. A bigger power supply may just cook things faster! |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 3222 |
The example code doesn't send anything to the LCD, it needs console connections for both. On the master you could use a TYPE statement following the Print to put it on the LCD also. |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 2002 |
No got the pico on the YSYS pin and the zero on the 5V pin which is also connected to the 5V rail on the breadboard, also put a wire from the 5V on the zero to VSYS. As the 2350A is now running the LCD off the usb I'm leaving the lithium battery off so I don't cook things as I tend to do  Also I have the LCD setup as console so what is seen on the com port it shown on the LCD Edited 2026-05-14 18:55 by Bryan1 |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 8842 |
Be careful with the Zero. You shouldn't connect its 5V pin if you have the USB connector linked to your PC. There's no isolation diode like there is between VBUS and VSYS on a Pico so you will back-feed 5V into your PCs USB. The 5V pin is VBUS, not VSYS - that isn't brought out. I doubt if its really safe to power it at all while the USB-C is connected as the onboard linear regulator can't be disabled either. I've not managed to kill one yet though. :) . Edited 2026-05-14 20:00 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 2002 |
OK been using list system I2C and it has been coming up blank yet when I removed the zero > list system i2c HEX 0 1 2 3 4 5 6 7 8 9 A B C D E F 00: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: 50 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- 68 -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- So powering up the zero from the 5V input may be the wrong way so how should I connect it as I do have the sample code from the manual on both the pico and the zero as a slave Edited 2026-05-14 20:13 by Bryan1 |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 2002 |
Yes my expensive pink C cable that was only available when I was in MT Isa for a shutdown was available to charge my phone I did notice it was hot when I took it off the zero. So I do need suggestions on how to power this zero as my setup just isn't working on my breadboard. Now all I'm trying to do is use the code in the pico manual and like always I'm finding the hardest part to do it. That is why this forum is so great and being a member since '05 trying to learn has been the hard part. Look once I can get this I2C working it may be time to having more fun as I did make a zero board to fit on the back of a camera detailed in the manual so I can use a 2040W to show a webpage of my water trough where I'm sure a we will see a few snakes taking a drink. I do have a huge black snake on the property and finding his skin is a good 5 paces, now that was out the back of my farm then oneday when I was driving out I saw him again, his head popped up and he took off across the road which is 5 metres wide as I did measure it. Now it took like ages before the tail arrived so this snake is only getting bigger as the years go by. Now when I go to my spring fed dam I always walk about a metre away from the reeds and I do hear rustling as the snakes are getting view to see if I'm a threat and to date they have seen I'm not a threat. Now for you pommy blokes this snake is No.3 on the list the Australian black snake now like said on my spring fed dam one day I went to pump a IBC of water and found a black snake under a cow pat so put my Honda pump on the ground primed it and filled the IBC. Went over the hill decanted the water using gravity and when I went back over that snake under the cow pat was gone and when I went to get out of cab a black snake did come at me so I just got back in the cab and let them settle then I saw the big snake do some justice to that young snake so I got out of the cab and filled my next IBC was uneventful. |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 3222 |
I can't get the example master / slave code from the manual to work either. With the code on the slave running List System I2C does show the slave address but no data goes in either direction. > list system i2c The slave is &H55, EEPROM &H57, RTC &H68, DHT10 &H38.HEX 0 1 2 3 4 5 6 7 8 9 A B C D E F 00: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- 38 -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: -- -- -- -- -- 55 -- 57 -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- 68 -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- Perhaps using serial instead may work. |
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| mozzie Guru Joined: 15/06/2020 Location: AustraliaPosts: 330 |
G'day, Bryan, if you want to use serial instead of I2C then that should be ok, I was only going to use the serial console if I went with the USB firmware to plug in a USB numeric keyboard to enter values, this is just another idea (one of many) The rest of the surface grinder software should still be the same either way. The whole E-Stop system is going to require some thought, I like your ideas using the PICO-ZERO as an option, however you will not be able to use the inbuilt homing system for the axis' without the limit inputs connected. More thinking required..... Also just thinking, I know if I plug 2 pico's of any type into my PC it'll only see the first one, might be why you are having trouble communicating with both. Regards, Lyle. Edited 2026-05-14 23:33 by mozzie |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 8842 |
When I'm messing with USB on things that don't isolate nicely I uses a USB isolator. Very useful thing to have in the toolkit! USB-A male on one end and female on the other. Just plug and play. The 3V3 regulator doesn't *appear* to suffer if the 3V3 pin is used as an input. The output mosfet in the RT9013-33 doesn't have a parallel diode and is switched off if there is no input. That's how I sometimes power a Zero. The USB connection is effectively isolated. Powering the Zero via the programming cable will also power the Pico over the same connection, whether the 5V supply is present or not! You could power the Pico at 5V and power the Zero at 3V3 from the 3V3 output of the Pico. You should be ok up to 100mA or so and the Zero won't take anything like that. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| mozzie Guru Joined: 15/06/2020 Location: AustraliaPosts: 330 |
G'day, Some testing has shown the example in the manual won't work, I2C write is no longer happy with a 1 length string, not sure how long that has been the case. The modified example below has been tested on RP2350 V6.03.00rc7 (TX+RX) and works: 'prog to test I2C comms as MASTER Option default integer SetPin gp26,gp27,i2c2 I2C2 open 100,1000 For i = 65 To 90 I2C2 write &h52,0,1,i Pause 500 I2C2 read &h52,0,8,A$ Print A$ Pause 500 Next End 'prog to test I2C comms as SLAVE Option default integer SetPin gp10,gp11,i2c2 I2C2 slave open &h52, iic_tint, iic_rint Do :Pause 50:Loop Until Inkey$<>"" End Sub iic_rint I2C2 slave read 10, r$, count Print Left$(r$, count), count End Sub Sub iic_tint T$=Time$ I2C2 slave write Len(T$), T$ End Sub Also works using I2C instead of I2C2, using 4K7 pullups on the bus in both instances. List System I2C and I2C Check can often lock up the devices on the bus, pays to reset the whole system before proceeding. Hope this helps  Regards, Lyle. Edited 2026-05-15 01:22 by mozzie |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 3222 |
I2C master & slave testing. The slave becoming unresponsive after using LIST SYSTEM I2C noted by Lyle appears to be due to the scanner only reading 1 byte. The last test below, "Master requesting data from slave." shows that the master must only request the exact number of bytes that the slave has ready to send. Requesting one more or less bytes than the slave data string results in the slave becoming unresponsive after that transaction. The slave program has to be stopped with Ctrl-C then started again. ' I2C slave program SetPin GP0, GP1, I2C I2C SLAVE OPEN &H52, TXint, RXint Do : Pause 5 : Loop Until Inkey$<>"" Sub RXint Local count, a$ I2C SLAVE READ 10, a$, count Print Left$(a$, count), count End Sub Sub TXint Local a$ = DateTime$(now) I2C SLAVE WRITE Len(a$), a$ Print "Slave sent = ";a$ End Sub Print "End" End ' Master sending data to the slave. > For n=65 To 75 :A$=chr$(n)+chr$(n+1)+chr$(n+2)+chr$(n+3)+chr$(n+4)+chr$(n+5) :I2C write &H52,0,6,A$ :Print A$, len(A$) :pause 999 :Next ABCDEF 6 BCDEFG 6 CDEFGH 6 DEFGHI 6 EFGHIJ 6 FGHIJK 6 GHIJKL 6 HIJKLM 6 IJKLMN 6 JKLMNO 6 KLMNOP 6 > Data received by slave from master ABCDEF 6 BCDEFG 6 CDEFGH 6 DEFGHI 6 EFGHIJ 6 FGHIJK 6 GHIJKL 6 HIJKLM 6 IJKLMN 6 JKLMNO 6 KLMNOP 6 ' Master requesting data from slave. > A$="":For n=0 To 25 :I2C read &H52,0,19,A$ :Print A$ :pause 999 :Next 'read 19 bytes, data sent = 19 bytes 15-05-2026 15:29:27 '19 bytes supplied by slave 15-05-2026 15:29:28 15-05-2026 15:29:29 15-05-2026 15:29:30 15-05-2026 15:29:31 15-05-2026 15:29:32 15-05-2026 15:29:33 15-05-2026 15:29:34 15-05-2026 15:29:35 > > A$="":For n=0 To 25 :I2C read &H52,0,18,A$ :Print A$ :pause 999 :Next 'read 18 bytes, data sent = 19 bytes 15-05-2026 15:29:5 'correct, 18 bytes supplied by slave but slave was expecting to supply 19 'Slave frozen > A$="":For n=0 To 25 :I2C read &H52,0,20,A$ :Print A$ :pause 999 :Next 'read 20 bytes, data sent = 19 bytes 15-05-2026 15:30:291 'correct, 20 bytes supplied by slave but slave was expecting to supply 19 'Slave frozen > Edit. One line I2C scanner that can read more than 1 byte. Set "B=" to the number of bytes that the slave is expecting to send and it won't get stuck. > B=19:A$="":For N=7 TO 119:I2C Read N,0,B,A$ :If MM.I2C=0 then :Print "I2C addr."N" = &H"+Hex$(n,2),"A$="A$:EndIf:Next'I2C Scanner I2C addr. 82 = &H52 A$=15-05-2026 21:35:47 > B=19:A$="":For N=7 TO 119:I2C Read N,0,B,A$ :If MM.I2C=0 then :Print "I2C addr."N" = &H"+Hex$(n,2),"A$="A$:EndIf:Next'I2C Scanner I2C addr. 82 = &H52 A$=15-05-2026 21:35:48 > 'I2C2 on the same pico > B=19:For N=7 TO 119:A$="":I2C2 Read N,0,B,A$ :If MM.I2C=0 then :Print "I2C addr."N" = &H"+Hex$(n,2),"A$="A$:EndIf:Next'I2C2 Scanner I2C addr. 56 = &H38 A$=Ê8E v×××Ê8E vÚÚÚÊ8 'AHT10 data I2C addr. 87 = &H57 A$=./0123456789:;<=>?@ 'EEPROM contents I2C addr. 104 = &H68 A$=¦! À8!& 'RTC data > Edited 2026-05-15 21:50 by phil99 |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 8842 |
That's always been the case when using I2C under MMBasic AFAIK. You need to send a message "This is how many bytes I'm going to send" then send a second message containing the bytes. Incidentally, MMBasic won't use SPI slave mode as it always produces the clock. At least, it wouldn't for me. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 2002 |
Ok new day so let the fun start I have been thinking about what went wrong the other night so just now fired up my laptop and got the zero connected in MCCC and the pico 2 connected on this computer in MCCC.Now I'm going to hookup that 10K/4K7 voltage divider to GPIO26 on the zero so it can measure the 2.5 volts @8 volts and get it to report to the pico2 via I2C. Regards Bryan |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 2002 |
Well that is strange got the code in the zero measuring the battery and the lithuim battery charger going yet the print of the voltage is staying on 7.6197 where the voltage is 8.636 on my DMM. DIM battery AS FLOAT SETPIN GP26, AIN DO battery = battery + 2.309 'scaling for battery voltage PRINT "Battery Voltage", battery PAUSE 1000 LOOP Well increased the scaling and now it's working and the only pins connected are the I2C and the ADC GP26 pin. I have noticed the zero is getting warm running of the USB too. On the pico 2 doing a list system I2C is coming up blank so the fun continues Edited 2026-05-16 12:53 by Bryan1 |
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