Junebug Assembly Tips - Page 3 - Electronic Circuits Projects Diagrams Free

blueroomelectronics · 10th November 2007, 11:45 AM

Those small reset switches are common here. Electrosonic, Mouser & Digikey have them. Creatron Inc brings them in cheap from China $0.22

The button under the 18F2550 is for a bootloader and the one on the tutor is manual reset for the 18F1320, you could use it as an input button but you'd have to reprogram it using the ICD connector as the tutor has constant power.

Don't forget to enable the weak pullup on port B for the switches... The IR test program will test button 1 too

**3v0** · 10th November 2007, 04:34 PM

Bill: I would like to get JuneBug to function as a programmer today. Am I right in thinking that I should use the resistor SIPs as indicated by the parts list and ignore the schematic ?

I have built the programmer part of the Junbug from the schematics. The software reports a short on the VPP line when testing. I will try replacing the sip resistors (I used discrete) with the values from the parts list where they do not agree. The again, it could be a real short and I have yet to find it.

For others building the board. The PK2 software on the PC. From the main menu do TOOLS>Troubleshoot.. This will allow you to test the analog circuits between the PIC and the target. Even generates a 30KHz signal on the clock and data lines so you can look at it with a scope. It is good stuff and I wish they had included it for the ICD2.

futz: Glad to be of help.

geko · 10th November 2007, 07:12 PM

Here's some photo's of my working Junebug as PK2.

http://picprojects.org.uk/junebug/

Note: I've used BC548/557 transistors so they're fitted the opposite way to the overlay. Also used a 470uH inductor and discrete 1/8 watt resistors in place of the SIP resistors.

geko · 10th November 2007, 07:49 PM

One other thing I've noticed on the Junebug.

On the schematics for the Microchip PICkit2 the Target Power LED connects to +5V; on the Junebug it connects to Gnd.

This makes the Target Power LED on the Junebug work with reverse logic i.e. Off when Target is powered, On when it's not.

Fit the LED the opposite way and connect the 330R resistor to the top of R15 (+5V). Here's a photo of my quick fix. (if you've already assembled it I would cut the leads off R8 rather than trying to remove it and be very careful not to lift the PCB tracks reversing the LED)

Mike, K8LH · 10th November 2007, 09:38 PM

Looks very nice. I'm envious.

Have fun guys. Mike

futz · 10th November 2007, 10:35 PM

Thought I'd join in the Junebug photo posting trend

These plastic "feet" really make it nice to use. They keep it from wandering around the desk and potentially frying itself on some other piece of equipment.

And just one of my Inchworm+/Unicorn:

blueroomelectronics · 10th November 2007, 11:36 PM

It looks great, nice work, you can now use the Unicorn as an LCD platform if you want.

blueroomelectronics · 10th November 2007, 11:39 PM

Quote:

Originally Posted by geko

One other thing I've noticed on the Junebug.

On the schematics for the Microchip PICkit2 the Target Power LED connects to +5V; on the Junebug it connects to Gnd.

This makes the Target Power LED on the Junebug work with reverse logic i.e. Off when Target is powered, On when it's not.

Fit the LED the opposite way and connect the 330R resistor to the top of R15 (+5V). Here's a photo of my quick fix. (if you've already assembled it I would cut the leads off R8 rather than trying to remove it and be very careful not to lift the PCB tracks reversing the LED)

The Target LED works but is reverse of a PICkit 2. I used the prototype design when testing the layout and switched the anode at the last minute. It doesn't affect operation so I left it.

blueroomelectronics · 10th November 2007, 11:46 PM

Quote:

Originally Posted by 3v0

Bill: I would like to get JuneBug to function as a programmer today. Am I right in thinking that I should use the resistor SIPs as indicated by the parts list and ignore the schematic ?

I have built the programmer part of the Junbug from the schematics. The software reports a short on the VPP line when testing. I will try replacing the sip resistors (I used discrete) with the values from the parts list where they do not agree. The again, it could be a real short and I have yet to find it.

For others building the board. The PK2 software on the PC. From the main menu do TOOLS>Troubleshoot.. This will allow you to test the analog circuits between the PIC and the target. Even generates a 30KHz signal on the clock and data lines so you can look at it with a scope. It is good stuff and I wish they had included it for the ICD2.

futz: Glad to be of help.

Both the SIPs and resistors will function the same, justs looks a little funky. The resistor values are marked on the PCB for the SIPs. The short could be the VPP cap is too low a voltage (16V, 22uf) make sure the DIP switch is off for testing. You can measure VPP on the ICD connector, there is a large gnd hole that will fit most meter probes in the upper left of the PCB. My VPP measures in at 12.1V

The PICkit 2 is rather well designed, even the standalone software is pretty handy. The UART terminal is pretty cool and supported in the Junebug design.

Don't forget you can name your Junebug

(you need to use the PICkit 2 software for this)

**3v0** · 11th November 2007, 04:41 PM

As I mentioned earlier I am building my JuneBug in three steps. It was tested at the end of each step prior to going on to the next.

1. Get the 18F2550 talking to the PK2 interface. (done - OK)
2. Add the analog parts to allow it to program debug. (done- OK)
3. Add the tutor parts. (to do)

I used 1/8 watt resistors in place or the 3 SIPs.

Tested the JuneBug with a 16F88 target and was impressed with how well it works with the MPLAB debugger. Stepping is quite fast, as is updating the SFRs. Anyone using a RS232 ICD2 (Inchworm) will appreciate the improvement in speed.

The rest of the build is mostly just the tutor processor socket, LEDs, and switches.

Problems:
None that were real. All the parts had the correct pinouts

and construction was straight forward. I made a few minor blunders along the way like testing VPP with my DVM on AC

. But the O-Scope showed it to be correct, only noticed that the DVM was on AC after I started writting this..

Earlier I posted about a problem with a VPP short. I should clarify that that was not with a real JuneBug PCB. Prior to getting the JuneBug PCB from Bill I had started construction on a JuneBug Clone without the tutor.

**3v0** · 11th November 2007, 06:59 PM

These are the parts numbers for JuneBug
So far I have switches and Semiconductors.
Added the inductor L1 and the USB connector CON1
I did not include the LEDs.

Octapart shows the supplier part numbers prices from several popular suppliers.

It would be nice if there was a way to change the order of parts in the list.

If you hit buy at the bottom of the page it will help you find the best deal
On the buy page it shows you each supplier and their price.
You can check the boxes Price Minimize In Stock and it will sellect the suppliers with the lowest price for in stock items.
You can then manualy reselect suppliers as you wish.
I have never tried ordering from this page.

Let me know if you like it. Is it worth finishing ?

blueroomelectronics · 11th November 2007, 08:08 PM

It's very handy 3v0 I could add to the parts list. I've used Omron switches both small and large.

PS here's a quick test for Mongoose

Code:

; Mongoose Hello World, right motor speed set by VR1
; jumper a small wire between VR1 and RA0 on the top connector       
         list     p=18F2525
         include <p18F2525.inc>
         CONFIG   OSC = INTIO67, PBADEN = OFF, WDT = OFF, LVP = OFF, DEBUG = ON
         
         org      0
         bsf      ADCON0,ADON
         clrf     LATB
         movlw    0xF0              ; RB0-3 motor direction outputs
         movwf    TRISB             ; RB4,5 optosensor inputs
         movlw    b'11111001'       
         movwf    TRISC             ; RC1,2 PWM outputs
         movlw    0x0F
         movwf    ADCON1            ; AD/RC Osc 
         movwf    CCP1CON           ; PWM mode
         movwf    CCP2CON        
         setf     PR2               ; PR2 = 255
         movlw    0x80              ; 50% PWM
         movwf    CCPR1L            ; left motor speed
         movwf    CCPR2L            ; right motor speed
         movlw    b'00000011'
         movwf    LATB              ; motor direction
         bsf      T2CON,TMR2ON      ; enable TIMER2
AD_GO    bsf      ADCON0,GO         ; start conversion
         btfsc    ADCON0,GO
         bra      $-2
         movff    ADRESH, CCPR1L   
         bra      AD_GO
         
    END

jeremygaughan · 12th November 2007, 01:53 PM

I'm also building along at home, but I can't seem to track down the P-channel mosfet. Actually I can't seem to get a hold of any P-channel mosfet. So I have two questions, is there a way around that part, and if not is it necessary for programming?

blueroomelectronics · 12th November 2007, 02:32 PM

The BS250 is only required for VPP before VDD programming. Just connect the Source to Drain connections and omit it (and the 2N7000 just don't install it)

jeremygaughan · 12th November 2007, 02:44 PM

Thanks for the quick help, I'll leave the place on my board for when I get back to the US and can get the part, but until that time I'll follow your advice. Another question that I have is, I get a verify problem with the 18F2550. It says "EEPROM error at 0x0000 good 0xFF bad 0x9E. Any idea what that could mean or be due to?

10th November 2007, 11:45 AM	(permalink)
blueroomelectronics Experienced Member Blog Entries: 4	Those small reset switches are common here. Electrosonic, Mouser & Digikey have them. Creatron Inc brings them in cheap from China $0.22 The button under the 18F2550 is for a bootloader and the one on the tutor is manual reset for the 18F1320, you could use it as an input button but you'd have to reprogram it using the ICD connector as the tutor has constant power. Don't forget to enable the weak pullup on port B for the switches... The IR test program will test button 1 too __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com

10th November 2007, 07:12 PM	(permalink)
geko Experienced Member	Here's some photo's of my working Junebug as PK2. http://picprojects.org.uk/junebug/ Note: I've used BC548/557 transistors so they're fitted the opposite way to the overlay. Also used a 470uH inductor and discrete 1/8 watt resistors in place of the SIP resistors. __________________ Pete picprojects.org.uk

10th November 2007, 10:35 PM	(permalink)
futz Experienced Member	Thought I'd join in the Junebug photo posting trend These plastic "feet" really make it nice to use. They keep it from wandering around the desk and potentially frying itself on some other piece of equipment. And just one of my Inchworm+/Unicorn: Last edited by futz; 12th November 2007 at 10:05 PM.

10th November 2007, 11:36 PM	(permalink)
blueroomelectronics Experienced Member Blog Entries: 4	It looks great, nice work, you can now use the Unicorn as an LCD platform if you want. __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com Last edited by blueroomelectronics; 10th November 2007 at 11:40 PM.

11th November 2007, 04:41 PM	(permalink)
3v0 Moderator Blog Entries: 3	As I mentioned earlier I am building my JuneBug in three steps. It was tested at the end of each step prior to going on to the next. 1. Get the 18F2550 talking to the PK2 interface. (done - OK) 2. Add the analog parts to allow it to program debug. (done- OK) 3. Add the tutor parts. (to do) I used 1/8 watt resistors in place or the 3 SIPs. Tested the JuneBug with a 16F88 target and was impressed with how well it works with the MPLAB debugger. Stepping is quite fast, as is updating the SFRs. Anyone using a RS232 ICD2 (Inchworm) will appreciate the improvement in speed. The rest of the build is mostly just the tutor processor socket, LEDs, and switches. Problems: None that were real. All the parts had the correct pinouts and construction was straight forward. I made a few minor blunders along the way like testing VPP with my DVM on AC. But the O-Scope showed it to be correct, only noticed that the DVM was on AC after I started writting this.. Earlier I posted about a problem with a VPP short. I should clarify that that was not with a real JuneBug PCB. Prior to getting the JuneBug PCB from Bill I had started construction on a JuneBug Clone without the tutor. Last edited by 3v0; 11th November 2007 at 04:54 PM.

10th November 2007, 04:34 PM	(permalink)
3v0 Moderator Blog Entries: 3	Bill: I would like to get JuneBug to function as a programmer today. Am I right in thinking that I should use the resistor SIPs as indicated by the parts list and ignore the schematic ? I have built the programmer part of the Junbug from the schematics. The software reports a short on the VPP line when testing. I will try replacing the sip resistors (I used discrete) with the values from the parts list where they do not agree. The again, it could be a real short and I have yet to find it. For others building the board. The PK2 software on the PC. From the main menu do TOOLS>Troubleshoot.. This will allow you to test the analog circuits between the PIC and the target. Even generates a 30KHz signal on the clock and data lines so you can look at it with a scope. It is good stuff and I wish they had included it for the ICD2. futz: Glad to be of help.

10th November 2007, 09:38 PM	(permalink)
Mike, K8LH Experienced Member	Looks very nice. I'm envious. Have fun guys. Mike

11th November 2007, 06:59 PM	(permalink)
3v0 Moderator Blog Entries: 3	OctaPart: JuneBug Parts These are the parts numbers for JuneBug So far I have switches and Semiconductors. Added the inductor L1 and the USB connector CON1 I did not include the LEDs. Octapart shows the supplier part numbers prices from several popular suppliers. It would be nice if there was a way to change the order of parts in the list. If you hit buy at the bottom of the page it will help you find the best deal On the buy page it shows you each supplier and their price. You can check the boxes Price Minimize In Stock and it will sellect the suppliers with the lowest price for in stock items. You can then manualy reselect suppliers as you wish. I have never tried ordering from this page. Let me know if you like it. Is it worth finishing ? Last edited by 3v0; 12th November 2007 at 06:06 AM.

12th November 2007, 01:53 PM	(permalink)
jeremygaughan Experienced Member	I'm also building along at home, but I can't seem to track down the P-channel mosfet. Actually I can't seem to get a hold of any P-channel mosfet. So I have two questions, is there a way around that part, and if not is it necessary for programming? __________________ jeremy

12th November 2007, 02:32 PM	(permalink)
blueroomelectronics Experienced Member Blog Entries: 4	The BS250 is only required for VPP before VDD programming. Just connect the Source to Drain connections and omit it (and the 2N7000 just don't install it) __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com

12th November 2007, 02:44 PM	(permalink)
jeremygaughan Experienced Member	Thanks for the quick help, I'll leave the place on my board for when I get back to the US and can get the part, but until that time I'll follow your advice. Another question that I have is, I get a verify problem with the 18F2550. It says "EEPROM error at 0x0000 good 0xFF bad 0x9E. Any idea what that could mean or be due to? __________________ jeremy

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