New IDE Card

[shift838]

Wanted to start a new thread for all updates rather than posting them to the poll topic.

I have received the prototype card today.  I will be doing a once over on it to make sure all is good (according to my schematics) then start populating it with components.

[shift838]

only found a few connection errors from my check that will require a few jumper wires.  will be starting to populate the board tomorrow.

[shift838]

Just need to add the IC's and I can test...

[- Ω -]

Looking good so far Chris!  I forget did you mention what the battery was for?  Did you slip in a RTC or is this to keep a programmable DSR active like on the HDX?

[shift838]

2 hours ago, - Ω - said:

Looking good so far Chris!  I forget did you mention what the battery was for?  Did you slip in a RTC or is this to keep a programmable DSR active like on the HDX?

The battery is used for the RTC, the original IDE card that had the older RTC chips had their batteries built into the IC and when they went out you had to Frankenstein it to get to the connections to hook up an external battery.  if you want to see one that I did check it out on my site:

https://www.shift838.com/bq4847-frank.html

 

[shift838]

Put one complete together and made the wire runs for the errors I found, just a few.  there is 2 issues I have to chase.

1.  Does not detect the clock chip for some reason.  I'm using the same circuitry design I used for my RTC module for the original IDE card.  I have gone to a 3.3v version of the RTC and SRAM as the 5v version of the BQ4802 is pushing $20 USD each.  The 3v version is 1/3 the price.

2. Does not keep time, whatever you set it does not cycle the seconds, it just stays at what you set it.  Almost sounds like a crystal issue.

I think once I fix the clock chip not being detected by Fred's IDE DSR loader it will fix #2 as well.

on the upside, I have plugged in a Transcend 44pin 4 meg module as you can see in the photo and was able to detect it, partition the unit with 4 partitions and initialize each partition no problem.

 

Almost there!

[- Ω -]

10 hours ago, shift838 said:

Put one complete together and made the wire runs for the errors I found, just a few.  there is 2 issues I have to chase.

1.  Does not detect the clock chip for some reason.  I'm using the same circuitry design I used for my RTC module for the original IDE card.  I have gone to a 3.3v version of the RTC and SRAM as the 5v version of the BQ4802 is pushing $20 USD each.  The 3v version is 1/3 the price.

2. Does not keep time, whatever you set it does not cycle the seconds, it just stays at what you set it.  Almost sounds like a crystal issue.

I think once I fix the clock chip not being detected by Fred's IDE DSR loader it will fix #2 as well.

on the upside, I have plugged in a Transcend 44pin 4 meg module as you can see in the photo and was able to detect it, partition the unit with 4 partitions and initialize each partition no problem.

 

Almost there!

 

I'm sure you'll get it all worked out.  Sorry, I have yet another question, is that clock 100% CorComp compatible?  If so, I may need to make another video... if you don't mind.

[shift838]

52 minutes ago, - Ω - said:

I'm sure you'll get it all worked out.  Sorry, I have yet another question, is that clock 100% CorComp compatible?  If so, I may need to make another video... if you don't mind.

The IDE clock is a different beast and the DSR is has completely different calls, for example in TI Basic to display both time and date you issue CALL IDETD and the IDE card will respond to show current date and time.  To pull specific time/date values from the IDE cards RTC you can use a small program for example:

100 OPEN #1:"IDE.TIME",INTERNAL,FIXED
110 INPUT #1:SEC$,MIN$,HOUR$,DAY$,MONTH$,YEAR$,DAYOFWEEK$
120 CLOSE #1

 

[shift838]

I found another error on the board, so I'm up to 5.  I have decided to make the entire board through-hole.  I have also made it compatible with any of my 838-RTC modules for the previous IDE board design.  So, this will allow someone to use an existing 838-RTC module for the clock.  I did have to swap a couple of address lines for the new through-hole 512k SRAM, but that was easy enough to do.

Here is the latest render.

[shift838]

update...

I have received the latest prototype boards and I have put one together and it functions so far with no issues.  Currently I have only tested on the TI-99/4A, but will be testing on the Geneve soon.

Changes:

• Fixed handful of connection errors
• Converted to a 100% through hole design with a different SRAM (had to re-route a couple of signals as they are different than the original design)
• The board now uses my 838 Clock module.  The one picture can use either the 3.3v or 5v version of the BQ4802.  The 3.3v is 1/3 of the price.

Please note, there are 2 connectors on the board.  You can only use one at a time.  If you need master/slave they need to be on the same connector.

Changes for production board:

• I want to use a larger, thicker and better heatsink help with the heat generated on the 7805 regulator if I don't go with a V7805-1500R which is better for heat (no heatsink required) - will require some capacitor change for the power and will increase cost by around $12 for the board.
• I will add ground planes.  Prototype did not have ground planes to make it easier if I needed to cut traces since there are quite a few signals on the board.

[shift838]

I have completed my testing on both the TI-99/4A and Geneve with the new IDE card.  I have been able to exercise all functions for IO operations on both TI and Geneve.  With the Geneve, I had to use the development version of MDOS to address the IDE issue (v7.42).

Please note, the RTC chip that will be offered will be the 5v version as it supplies the voltage required for the SRAM control and the 5v version seems to be more stable, this does increase the price of the board by around $15.

Preorders will open soon.  I still want to put it through some more paces before on both the TI and Geneve.  

I will also be replacing the standard 1.5 amp 7805 voltage regulators with a 2amp DC/DC converter.  It runs much more stable and the heat it generates is on average between 40 - 50 degrees cooler than the LM7805.