HRD 4000B

[NewcomerTI]

Hi Ksarul,

 

I’m interested in one assembled 8M and one bare boards if you still have these available.

Ty

[+Ksarul]

16 hours ago, NewcomerTI said:

Hi Ksarul,

 

I’m interested in one assembled 8M and one bare boards if you still have these available.

Ty

I still have plenty of bare boards available. I have an assembled board that I need to run through a shakedown test over the next day or two. I've been delayed over the last few weeks due to COVID-19 (it infected me and I avoided touching any of my hobby gear until I was sure I was fully clear)

[+retroclouds]

12 hours ago, Ksarul said:

I still have plenty of bare boards available. I have an assembled board that I need to run through a shakedown test over the next day or two. I've been delayed over the last few weeks due to COVID-19 (it infected me and I avoided touching any of my hobby gear until I was sure I was fully clear)

 

Jim, truly hope you are doing fine and that COVID-19 didn’t cause you too much troubles.

[+FALCOR4]

On 8/7/2020 at 12:40 PM, FALCOR4 said:

A software developers guide for the HRD4000B.  Special thanks to Ksarul, InsaneMultitasker, Retroclouds and BeeryMiller for their inputs.

 

I corrected an error in this version of the "software developers guide to the HRD4000B"; this is ver 1.1

 

Barring any significant inputs from the community, I will call it done.  Thanks everyone!

 

Software Developers Guide to the Horizon HDR4000B_ver_1-1.pdf

[Shift838]

I'm in the process of building my HRD4000B card.  I have already done the initial 'SMOKE TEST' with no issues.  Now I'm to the point of doing the MEGTEST program.

 

I have been following the construction guide, but I may be confused on it.  It states:

 

THE INTEGRATED CIRCUITS
Insert all ICs except for the memory chips. Make sure the notch of each IC points toward the top of the card (for the chips mounted vertically) or to the left (for the chips mounted horizontally), as shown in Figure 6. Install U9, the 6264LP-15, near the center of the board. TO AVOID MEMORY DAMAGE, NEVER PLACE THE CARD IN THE PEB WITHOUT ITS BATTERIES! Run the MEGTEST program as described in the MEGTEST instructions.

 

Now from my understanding the megtest program can run a simple U11 test, Memory Test and Loop test.  So but with the statement above from the construction guide is interpreted (by me) that I do not install the memory chips just yet and still run the MEGTEST.  If so, then what option do I need to choose?  U11 or what?

 

Or is this part of the guide wrong and i need to install the memory chips and set the jumpers before running any test with MEGTEST ?

 

 

 

 

[+FALCOR4]

3 hours ago, Shift838 said:

I'm in the process of building my HRD4000B card.  I have already done the initial 'SMOKE TEST' with no issues.  Now I'm to the point of doing the MEGTEST program.

 

I have been following the construction guide, but I may be confused on it.  It states:

 

THE INTEGRATED CIRCUITS
Insert all ICs except for the memory chips. Make sure the notch of each IC points toward the top of the card (for the chips mounted vertically) or to the left (for the chips mounted horizontally), as shown in Figure 6. Install U9, the 6264LP-15, near the center of the board. TO AVOID MEMORY DAMAGE, NEVER PLACE THE CARD IN THE PEB WITHOUT ITS BATTERIES! Run the MEGTEST program as described in the MEGTEST instructions.

 

Now from my understanding the megtest program can run a simple U11 test, Memory Test and Loop test.  So but with the statement above from the construction guide is interpreted (by me) that I do not install the memory chips just yet and still run the MEGTEST.  If so, then what option do I need to choose?  U11 or what?

 

Or is this part of the guide wrong and i need to install the memory chips and set the jumpers before running any test with MEGTEST ?

 

 

 

 

Chris, I only used the U11 test.  I couldn't get MEGTEST to work properly to test the memory on the HRD4000B but, that is very well just me.  I didn't spend a lot of time trying to figure it out.  After I put it down I just wrote some hack code to fill up all memory and then read it back using the MG Explorer.  

 

So, you should be able to test U11 before you install the rest of the SRAM.  If memory serves......

 

Ksarul, did you get the Memory Test option to work for you?

[Shift838]

53 minutes ago, FALCOR4 said:

Chris, I only used the U11 test.  I couldn't get MEGTEST to work properly to test the memory on the HRD4000B but, that is very well just me.  I didn't spend a lot of time trying to figure it out.  After I put it down I just wrote some hack code to fill up all memory and then read it back using the MG Explorer.  

 

So, you should be able to test U11 before you install the rest of the SRAM.  If memory serves......

 

Ksarul, did you get the Memory Test option to work for you?

But do I need to configure any of the jumpers or just set the CRU address for this initial test?  I believe on the CRU needs to be set, just making sure.

 

 

Edited November 6, 2020 by Shift838

[+mizapf]

I'm currently reworking the Horizon emulation in MAME. Some questions:

 

I saw that you can put two different kinds of memory chips on the board (128Kx8 and 512Kx8). Also, you can put a maximum of 32 chips on the board (stacked in two layers). Chips must not be mixed; what else has to be considered?

 

- Does the bottom layer have to be completely filled?

- The top layer seems optional. Can you fill it partly?

- Can you fill each layer partly?

 

If layers have to be filled, you'd only have options for 16 or 32 chips. If only the bottom layer must be filled, you'd have min 16, max 32 chips. If the bottom layer need not be filled, you could have 1-32 chips, where the first 16 chips belong to the bottom layer (unless both layers could be partly filled).

 

I recently posted some more questions:

 

1. The only difference between HRD4000 and HRD4000B is the switchable DSR bank, right? (CRU bit 14)

2. How do HRD3000 and HRD3000B differ?

3. Is the HRD4000(B) the only HRD that decodes AMA/B/C?

4. Is "HRD2000" = "HRD+ Series 2000?"

5. Is there any further difference between HRD+ and HRD2000 besides the stacking of control chips?

[+FALCOR4]

2 hours ago, Shift838 said:

But do I need to configure any of the jumpers or just set the CRU address for this initial test?  I believe on the CRU needs to be set, just making sure.

 

 

Just set the CRU address

[+FALCOR4]

2 hours ago, mizapf said:

I'm currently reworking the Horizon emulation in MAME. Some questions:

 

I saw that you can put two different kinds of memory chips on the board (128Kx8 and 512Kx8). Also, you can put a maximum of 32 chips on the board (stacked in two layers). Chips must not be mixed; what else has to be considered?

 

- Does the bottom layer have to be completely filled?

- The top layer seems optional. Can you fill it partly?

- Can you fill each layer partly?

 

If layers have to be filled, you'd only have options for 16 or 32 chips. If only the bottom layer must be filled, you'd have min 16, max 32 chips. If the bottom layer need not be filled, you could have 1-32 chips, where the first 16 chips belong to the bottom layer (unless both layers could be partly filled).

 

I recently posted some more questions:

 

1. The only difference between HRD4000 and HRD4000B is the switchable DSR bank, right? (CRU bit 14)

2. How do HRD3000 and HRD3000B differ?

3. Is the HRD4000(B) the only HRD that decodes AMA/B/C?

4. Is "HRD2000" = "HRD+ Series 2000?"

5. Is there any further difference between HRD+ and HRD2000 besides the stacking of control chips?

VERY good questions.  I may be able to answer most of them but, grandkids in the house right now so give me a day or so ?

[+Ksarul]

On memory chips: you can start with less than 16 chips, you just have to follow the instalation order listed in the manual. The bottom layer has to be filled before starting to fill the top layer (which can also start with less than 16 chips). Depending on the jumper settings, you can use 128K OR 512K chips, but all installed chips must be of the same capacity. Note that when using the 512K chips, each layer has a maximum of 8MB. Two layers is then too much for the CFG program to segment into drives. You could use the split board option to make a 16M board into two 8M RAM Disks--this has not been tested yet with more than one layer of chips (giving two 4MB configurable RAM Disks), so you will be in uncharted territory if you try it.

 

The HRD 4000 also decodes AMA/B/C, as I used the same circuitry on the 4000B. I'd have to do some research on earlier schematics to see when that circuitry first arrived.

 

There are other minor differences between the 4000 and the 4000B. Several pull-up resistors were added, the DSR RAM chip must be a 32K chip (the 8K option is gone), and the chip select is no longer controlled by the seriously suspect linkage through the center LED. The board also has the options to select between the various battery types baked into it.

 

I'd have to pore over the older schematics to answer your other questions on earlier board revisions, @mizapf

[+mizapf]

OK, this means I can offer an option for the RAM type (128Kx8 / 512Kx8) and a number of RAM circuits from 1 to 32, with the assumption that the numbers 1-16 fill up the circuits in the bottom layer contiguously, then 17-32 continue on the top layer. Maybe it would suffice to offer 0 / 8 / 16 / 24 / 32 chips as options to cover all interesting cases.

 

The types 4000 vs. 4000B would then imply to have a 8K vs. 32K DSR chip with the appropriate decoding.

 

From the schematics I did not quite understand the idea of the second LED in the middle of the board.

 

If feasible, I'd like to add the types 2000 and 3000 as well. If this turns out to complicate things too much, I'd have to define them as a distinct card.

[+FALCOR4]

9 hours ago, mizapf said:

From the schematics I did not quite understand the idea of the second LED in the middle of the board.

That LED is part of a circuit that protects memory from corruption during power cycles.  It became necessary (from what I've read) when ROS 8.+ was introduced that used HRD SRAM as a disk buffer instead of VDP RAM revealing instances of memory corruption.  It's a bit unusual of a design but it works.  I believe it is known as change 3 or change 91-1 in the Horizon literature.  Someone more familiar with the Horizon RamDisk history fact check me here.

 

BTW, I recommend using a blue LED because the forward voltage drop is generally greater than the other colors.  It offers a bit more margin for protection.

[+FALCOR4]

5 hours ago, mizapf said:

If feasible, I'd like to add the types 2000 and 3000 as well. If this turns out to complicate things too much, I'd have to define them as a distinct card.

The problem with the earlier versions is that there were many modifications and configurations the popped up over the years.  It might be difficult to account for those.   Again, fact check me.  I'm only going off of what I have personally seen and read.

[RickyDean]

3 hours ago, FALCOR4 said:

The problem with the earlier versions is that there were many modifications and configurations the popped up over the years.  It might be difficult to account for those.   Again, fact check me.  I'm only going off of what I have personally seen and read.

I believe using the base of each would be sufficient, the 2000 could only use 32k chips for populating, the 3000 was capable of using 32k or 128k chips. Both could be layerd up to a certain range. What they did was basically the same.

Edited November 7, 2020 by RickyDean
punctuation and spelling.

[+FALCOR4]

36 minutes ago, RickyDean said:

I believe using the base of each would be sufficient, the 2000 could only use 32k chips for populating, the 3000 was capable of using 32k or 128k chips. Both could be layerd up to a certain range. What they did was basically the same.

Very good point, thanks RickyDean.  And I believe that they had 12 not 16 SRAMs for a first layer?

[RickyDean]

17 minutes ago, FALCOR4 said:

Very good point, thanks RickyDean.  And I believe that they had 12 not 16 SRAMs for a first layer?

12 sram, not counting the 8k dsr chip. I have two 2000 series, one 3000, one 3000b, one 4000, and boards for 2 4000b's when finances come available to populate them. I built all but one of the 2000's myself, back in the day.

[+mizapf]

But the schematics that I found for the 2000 and 3000 show 32 RAM chips, just like the 4000 type. Or were those 2000 cards not fully populated?

[+InsaneMultitasker]

I have an 8MB 3000 series populated with 16 x 512 chips. If I recall correctly, the bottom layer is fully populated and there are 4 chips on the top layer.  We had toyed around with adding another 16 chips to the card to bring the total size to 16MB as the hardware and CRU addressing should in theory support it, though the practical value truly starts to diminish beyond the 8MB capacity unless you have a way to reload the disks or as in the case of the Geneve (hopefully soon) a way to copy the entire "partition". 

[+mizapf]

Ah, the Horizon 3000 manual talks about a "piggy-back board" when you wanted to go above 1.5 MiB. Also, it seems as if the Horizon 2000 and 3000 could have stacks of up to 3 chips. Since all chips were SRAM, it suffices to connect them by a single separate wire (pin 20), and apart from that, solder all pins together.

[RickyDean]

1 minute ago, mizapf said:

Ah, the Horizon 3000 manual talks about a "piggy-back board" when you wanted to go above 1.5 MiB. Also, it seems as if the Horizon 2000 and 3000 could have stacks of up to 3 chips. Since all chips were SRAM, it suffices to connect them by a single separate wire (pin 20), and apart from that, solder all pins together.

Yeh, you could stack'em and on some like the 4000, you could use up to 512k chips natively.  The 2000's and the insane one talked about could be modified,  as Falcor4 talked about, alot. So I would just use the base models and maybe give options for more ram from there. That way those emulating their rigs can interchange data, as the insane one gets the software setup for it.

[Shift838]

6 hours ago, FALCOR4 said:

Chris, I only used the U11 test.  I couldn't get MEGTEST to work properly to test the memory on the HRD4000B but, that is very well just me.  I didn't spend a lot of time trying to figure it out.  After I put it down I just wrote some hack code to fill up all memory and then read it back using the MG Explorer.  

 

So, you should be able to test U11 before you install the rest of the SRAM.  If memory serves......

 

Ksarul, did you get the Memory Test option to work for you?

I have ran the MEGTEST program and all tests passed without the memory chips.  Added 16 512k x 8 along with the additional 74HCT154 and set the jumpers for 512k x 8 and ran the test again, all passed.

 

Card is set to CRU 1600 and used form3meg to format the ramdisk.  I am thinking i am only seeing 4mb of the 8mb ram installed.

 

I believe(someone correct me if i'm wrong) i should have close to 25000 sectors to take over the 8mb but I am only seeing 12792 sectors after formatted.

 

Am I doing something wrong that needs to be set differently to get the full 8mb ramdisk ?

 

 

 

 

 

 

[+InsaneMultitasker]

13 minutes ago, Shift838 said:

Card is set to CRU 1600 and used form3meg to format the ramdisk.  I am thinking i am only seeing 4mb of the 8mb ram installed.

This tells me you are using the card with the Geneve.  Maximum capacity is a "floppy" format at 12,800 sectors, where each allocation unit represents 8 sectors.  This format works but there are some cluster calculation issues that may bite you as the disk is filled. Geneve OS/MDOS v7.0 allocates a single floppy 'disk'  (for booting) and the remainder as a hard drive formatted 'disk', however, it is not yet released. 

[Shift838]

4 minutes ago, InsaneMultitasker said:

This tells me you are using the card with the Geneve.  Maximum capacity is a "floppy" format at 12,800 sectors, where each allocation unit represents 8 sectors.  This format works but there are some cluster calculation issues that may bite you as the disk is filled. Geneve OS/MDOS v7.0 allocates a single floppy 'disk'  (for booting) and the remainder as a hard drive formatted 'disk', however, it is not yet released. 

so I can't use the full 8mb of ramdisk with MDOS 6.5 ?

[+InsaneMultitasker]

4 minutes ago, Shift838 said:

so I can't use the full 8mb of ramdisk with MDOS 6.5 ?

Correct.   https://github.com/horizonramdisk/Horizon-Ramdisk-ti994a/wiki/Geneve

 

(you could use full capacity in rompage mode but that would preclude usage in the native OS)