[SOLVED] Project to replace CY7C64613 in the ICD2

[3v0]

Thanks for the info on the inductors. I was thinking that 1/4W resistors might be too large for the way the board is laid out. The spacing looks tight and there are resistors under the microprocessors.

 

[manu]

Re: Yes, It's my PCB version 2.

I searched for 100uH inductors on the Mouser site and came to understand that I did not have enough info to choose one.

Could you provide a manuf and part number for the inductors.

Have a glance to coilcraft website :

https://www.coilcraft.com/

They could send you free samples !

 

[Sreedharan]

Hi Guys,
First of all thanking you for the great work.Today I could also build ICD2 successfully.I also had to struggle litle bit clearing out the problems so just a few tips to start with.
I tested the RS232 based design first using Lothar Stolz design,then rigged the PIC18f4550 part .Since i didnt have mc34064a ,i had to give external power supply (12 v),could also run the self test succesfully.I connected PICDEM2 plus as the target board and it cud detect my target.I also noticed that icd2 cudnt detect target without 12V Vpp power supply in ICD ,even though my target had 5V Vdd seperatley.
Guys please help me in resolving this issue.
Also i suggest to add the RS232 circuit to USB so that we could also carry out the diagnostics properly.
Thanks,
Sree

 

[Kripton2035]

I also noticed that icd2 cudnt detect target without 12V Vpp power supply in ICD ,even though my target had 5V Vdd seperatley.
Guys please help me in resolving this issue.

it is totaly normal as the 12v is the programming voltage for the pic devices (i.e. some 13v are needed depends on the pic ) and that voltage is needed too to put the pic in programming mode to detect the target... not a problem at all..

 

[medvonok]

For MC34063A, all resistors are 0,25W ? Especiali between pin 6 and 7.
Pin MCLR (4550) are a resistor 10k for pull up ?

 

[caproni]

hi caproni,
you had test to put the RA4 to VCC to reprogram 4550? please answer! thanks!
i hope your response.

Hi emcs51:

Sorry for the delay. I was very busy.

Today I tried put the RA4 to VCC. So:

With RA4 to GND, I connected to USB normally.

If I change RA4 to VCC, the USB disconnects.

Guys, I´m going crazy...

I bought some boards from a friend , good ones, but they didn't works.

Potyo, can you please explain the mode of use 4550 bootloader hex/ RA4 pin ??

Thanks a lot

Regards

Rodolfo

 

[Andy_123]

caproni:
RA4 should be connected to GND.

======================

Anyone knows what exact el.pot used in the original ICD2 device?

MCP41010 - 10K
or
MCP41050 - 50K
or
MCP41100 - 100K

Thanks

 

[mamaboss]

Andy_123 :

I have original ICD2.

MCP41010 used.

 

[Andy_123]

Are these resistor values correct?

With el.pot=0, output voltage will be over 50V!

With el.pot=10K, output=11.5V

to get 13V, pot must be at about 8.5K

Vout=1.25*(1+R23/(R22+POT))

Just want to make sure.

 

[polymath]

Hi Andy_123
My calcs confirm yours - divider network is far from optimum.

with POT at mid-value 10k/2=5k0     ref voltage = 1v25

Output voltage = (100k+2k2+5k0)(1.25/(2k2+5k0))

 = 107k2*1.25/7k2 = 134/7k2 = 18.6 volts     (mid value)


with POT at max == 8k - (min spec)

Output voltage = 108k*1.25/10k2 = 135/10k2 = 13.2 volts      (min value)


with pot at min == 0k175 - (max spec)

 = 100k175*1.25/2k375 = 125.22/2k375 = 52.7 volts       (mav value)

I have seen values of 3k3 in www.mcu.cz and fixed values of 100k/10k62


Hi mamaboss
Can you tell us what values you have in your ICD2 - please?


regards ... Polymath

 

[Andy_123]

I'll wait until somone with real ICD responds.

I guess R22 should be around 6K or R23 should be reduced to protect against 50V!

Best values I can calculate with Rpot=10K

R22=24K
R23=270K

Vmax=15.3V
Vmid=12.88V
Vmin=11.18V

 

[medvonok]

Can help you this ?
**broken link removed**

Added after 4 minutes:

Resistor between pin 6 and pin 7, are 0,25W ?
Vpp is 13,2 V ?

 

[bendjy]

Hi Andy_123

My original ICD2 is with MCP41100 and MIC2145 ( not 34063 ) in bootstrap configuration ( see www.micrel.com).

regards
bendjy

 

[bendjy]

Here is my version of ICD2 PSU. With target uC 16f877 Vpp=12.5V

bendjy

 

[Andy_123]

bendiy

I think your version is closest one I have seen so far
but it is still has middle point(5K) at the bottom of the range.

Vmax=16.4 Rpot=0K
Vmid=11.8 Rpot=5K
Vmin=10.7 Rpot=10K

I would try to keep midpoint around 12.5-13V

 

[stroma]

Hi Andy_123,
as bendjy said original icd2 uses micrel MIC2145 as a dc-dc converter which operate with very small current through comparator divider R22-R23. this allows R22 = 1Mohm, and R23=82Kohm. MIC2145 have Uref=1.08 V which gives output voltage in range
Umin = 12.8V Umid = 13.5V and Umax = 14.2 V. this were discussed in previous thread about icd2 @ this forum …

MC34063A haven’t good regulation with such high resistance divider. In my old icd2 design (with cypress usb chip) I used MC34063A with R22 = 470k and R23=44k and I got Umin = 12.1V, Umid = 13.2V, Umax = 14.6 V. it works well with target pics which I use.

Better replacement for MIC2145 is TL497 – it works with R22 = 1Mohm without problems but is hard to find for me and bigger than MC34063A.

I like idea for 12f683 vpp generator suggested by potyo (I was thinking about same thing some time ago). Thanks potyo – good design and code. Did you test it it in real icd2? Is it working well?

Best regards
stroma

 

[potyo]

I like idea for 12f683 vpp generator suggested by potyo (I was thinking about same thing some time ago). Thanks potyo – good design and code. Did you test it it in real icd2? Is it working well?

This is not my idea. It's author is MIKE, K8LH. I've tested it, and works fine, but if the voltage on the original icd2 is between 12.8 and 14.2V, i can't see reason to use a variable voltage generator.

 

[mamaboss]

My original ICD2 is with MCP41010 and MIC2145.

 

[stroma]

This is not my idea. It's author is MIKE, K8LH. I've tested it, and works fine...

Sorry potyo/MIKE it’s my mistake. Never mind – I’m planning to build a icd2 design with 12f683 vpp generator.

...but if the voltage on the original icd2 is between 12.8 and 14.2V, i can't see reason to use a variable voltage generator.

But if there is no reason for variable vpp generator why original icd2 have one?
best regards
stroma

 

[R2D1]

Could anyone with original ICD2 check the circuit on RC3 (37), RC4 (42), RC5 (43) of 877A? I would like to confirm the original buffer design.

Thanks a lot!