Micro-KIM address decoding design flaw and fix

Discuss problems with your Micro-KIM here

Micro-KIM address decoding design flaw and fix

Postby vbriel » Sep Sun 02, 2007 9:50 am

Well, as hard as I tried not to have any errors, I found one. It is a address decoding error that only shows up when you try to add a 2nd 6532. Under normal board operation it works fine, but if you add a 2nd 6532 it won't address correctly. What happened is I accidently tied a decoding line to VCC instead of A6. There is a fix and it isn't that hard. For anybody who can't do this fix, let me know!

Here is a page describing the bug and the fix.

http://www.brielcomputers.com/mkbug.html

Ok, if somebody comes up with a better way to fix this, let me know. I have applied this fix and it works correctly to decode the 2nd 6532.

Before I got this announcement up I fix a couple of boards that I built. If you recently purchased your Micro-KIM, look between the circuit board and the socket in the front where the curve part is. If you see a small rework wire then your board has a patch applied. If not, you may want to do this fix.

Vince
User avatar
vbriel
Site Admin
 
Posts: 1184
Joined: Jul Tue 19, 2005 12:10 pm
Location: Ohio

Postby vbriel » Sep Fri 21, 2007 7:41 pm

The fix is a 2 part fix and should be the last fix required. Once the initial fix was done, it has been discovered that the upper 64 bytes of RAM in the 6532 was not available. This will fix that problem.
User avatar
vbriel
Site Admin
 
Posts: 1184
Joined: Jul Tue 19, 2005 12:10 pm
Location: Ohio

Postby hanso » Sep Wed 26, 2007 2:36 pm

I have applied both fixes, nice pictures!

Alas, I lost the serial interface, the keypad works fine with all fixes

So I reversed the changes and found out:
1. the first fix A6 to 74LS138 pin 1 is fine, serial works
2.the cut at pin 10 and connect between pin 9 and 10 of the 74LS00 is fine also, serial works
3. the cut at pin 13 and connect at pin 13 to pin 8 of the other 74ls00 breaks the serial

Crossing the cut with the now soldered wire again makes the serial work again, with fix 1 and 2 still present

Am I doing something wrong here?
hanso
 
Posts: 71
Joined: Sep Sat 22, 2007 12:35 pm
Location: Weesp The Netherlands

Postby vbriel » Sep Wed 26, 2007 3:56 pm

No, there is one more step I need to add. I'll try and get it posted tomorrow.

The final step is up. The fix only applies to rev 0 boards.

Vince
User avatar
vbriel
Site Admin
 
Posts: 1184
Joined: Jul Tue 19, 2005 12:10 pm
Location: Ohio

Postby mike3 » Oct Wed 10, 2007 6:27 pm

are all the fixes now posted? ....

>>>>>>>>Mike
mike3
 
Posts: 12
Joined: Jul Sat 28, 2007 7:57 am

Postby vbriel » Oct Thu 11, 2007 5:39 am

Yes, you can view them here:

http://www.brielcomputers.com/mkbug.html

Remember this only pertains to rev 0 boards. Boards that are shipping now are revision 1 with this fix applied.

Vince
User avatar
vbriel
Site Admin
 
Posts: 1184
Joined: Jul Tue 19, 2005 12:10 pm
Location: Ohio

Postby mike3 » Oct Thu 11, 2007 1:11 pm

Thanks... The reason I asked.. is I wanted to wait untill all fixes were in before I did them.. to get them all at once...
By the way I orderd and built the 32K board.. can you say which if any other expansion boards are forthcoming? .....

Thanks........
>>>>>>>>>>Mike
mike3
 
Posts: 12
Joined: Jul Sat 28, 2007 7:57 am

Postby vbriel » Oct Thu 11, 2007 2:31 pm

Hi Mike,

Well, I have a few items in mind to complete the Micro-KIM, such as the 2nd 6532, a small expansion bus, the cassette interface but progress is slowed by home life time plus I have some replica 1 projects to wrap up this year. Still, things will progress at a rapid pace once the VCF X is over. Look for more goodies in the near future!

By the way, now is a good time to ask if there is any interest in converting the CFFA1 to work with the Micro-KIM?

Vince
User avatar
vbriel
Site Admin
 
Posts: 1184
Joined: Jul Tue 19, 2005 12:10 pm
Location: Ohio

Postby Bill Loguidice » Oct Thu 11, 2007 3:19 pm

vbriel wrote:
By the way, now is a good time to ask if there is any interest in converting the CFFA1 to work with the Micro-KIM?

Vince


That's intriguing. Do you mean it can be made to work with both, or it would be a one way conversion that would then only work on the Micro-KIM?
User avatar
Bill Loguidice
 
Posts: 35
Joined: Jun Mon 04, 2007 9:05 am
Location: Central New Jersey, USA

Postby Jeroen » Oct Thu 11, 2007 3:46 pm

I guess the hardware's compatible. it's just a matter of software.....
Jeroen
 
Posts: 38
Joined: Sep Fri 28, 2007 2:47 am

Postby mike3 » Oct Thu 11, 2007 4:35 pm

Can't wait for the Goodies....

I would be interested in the CFFA1.... I have the CFFA for my Apple IIe,GS ....and am very happy with it....

>>>>>>>>Mike
mike3
 
Posts: 12
Joined: Jul Sat 28, 2007 7:57 am

Postby vbriel » Oct Thu 11, 2007 9:40 pm

Well, I would have to make an adapter board, very minor but the I/O on the replica 1 and apple 1 is different than the KIM-1 and Micro-KIM. The firmware on the CFFA1 would have to be modified but it can be done if there is enough interest. I would think at least 5-10 people would be need to be interested in order to ask Rich to mod the code.

I have a CFFA for my IIplus but the CFFA1 is slightly differnt. It has a built in menu system for loading and storing programs in a prodos compatible file format. So, you can take a CF card out and put it in your gs and read the files! Very useful.

Vince
User avatar
vbriel
Site Admin
 
Posts: 1184
Joined: Jul Tue 19, 2005 12:10 pm
Location: Ohio

Postby hanso » Oct Fri 12, 2007 1:16 am

vbriel wrote:Hi Mike,

Well, I have a few items in mind to complete the Micro-KIM, such as the 2nd 6532, a small expansion bus, the cassette interface but progress is slowed by home life time plus I have some replica 1 projects to wrap up this year. Still, things will progress at a rapid pace once the VCF X is over. Look for more goodies in the near future!

By the way, now is a good time to ask if there is any interest in converting the CFFA1 to work with the Micro-KIM?

Vince


Yes, good ideas:

- 6532 + cassette interface to make it a complete KIM-1 clone and ready for I/O experiments
- CFFAA1 adapted to the KIM-1 would make it a very usable computer!
- expansion bus to add cards with for example a 6551 for more convenient serial communication or a 6522

Hans

FOr the cassette interface: please prepare for motor on/off control for two cassette recorders, e.g. with small relays. The 'standard' way for this is described in the Micro-Ade manual.
hanso
 
Posts: 71
Joined: Sep Sat 22, 2007 12:35 pm
Location: Weesp The Netherlands

Postby hanso » Oct Fri 12, 2007 1:23 am

vbriel wrote:Yes, you can view them here:

http://www.brielcomputers.com/mkbug.html

Remember this only pertains to rev 0 boards. Boards that are shipping now are revision 1 with this fix applied.

Vince


I have done all three fixes, and it made Micro-Ade function.
I checked that the whole RAM area of 128 bytes of the 6532 are available and mapped to the right location.

Hans
hanso
 
Posts: 71
Joined: Sep Sat 22, 2007 12:35 pm
Location: Weesp The Netherlands

Postby vbriel » Oct Fri 12, 2007 6:28 am

hanso wrote:
Yes, good ideas:

- 6532 + cassette interface to make it a complete KIM-1 clone and ready for I/O experiments
- CFFAA1 adapted to the KIM-1 would make it a very usable computer!
- expansion bus to add cards with for example a 6551 for more convenient serial communication or a 6522

Hans

FOr the cassette interface: please prepare for motor on/off control for two cassette recorders, e.g. with small relays. The 'standard' way for this is described in the Micro-Ade manual.


I really would like a 6551 interface like I just did with the replica 1, it is very useful. So, do you want a 6532 and cassette in one board? I can do it that way. I will look up the motor on/off control for two cassette recorders in the Micro-Ade manual and see what is required.

I was thinking 3 connector expansion but maybe we meed 5-6 for that much expansion!

Vince
User avatar
vbriel
Site Admin
 
Posts: 1184
Joined: Jul Tue 19, 2005 12:10 pm
Location: Ohio


Return to Troubleshooting

Who is online

Users browsing this forum: No registered users and 1 guest

cron