SBC 2.5 availability/order?

[8BIT]

Martin_H wrote:

I took the parts list and went to Mouser and composed a spreadsheet of parts ... I'm unsure if I located the correct TTL oscillator.

Yes, that part will work. Also, I recommend Garth's advice and switch from 74LS to 74HC parts.

I also recommend his suggestion to buy larger pin headers and then snap them apart to fit the correct size. You can buy two of these 2x36 headers (649-77313-122-72LF) for $4.58 and get rid of these:
2x3 headers 855-M22-2020705 2 $1.02 $2.04 J1 ROM OPTS & OPT2
2x5 pin header 649-77313-122-10LF 2 $0.59 $1.18 JP1 & OPT1
2x7 pin header 649-77313-101-14LF 4 $0.53 $2.12 P-1 to P-4
2x25 pin header - Expansion Port 517-929665-01-25-I 1 $3.50 $3.50 J12 Expansion Port

The 2x25 and 2 2x5's will fit on one and the rest will fit on the second.

Daryl

[Martin_H]

@all, thanks for the suggestions. I've modified the parts list to contain the HC logic parts, and two 2x36 header pins. This reduced the price by about $4. My goal in compiling the parts list was to get a feel for the cost, and see if all the parts were available before I considered organizing a bulk order for the PCB. But I've noticed a problem with the 32 KB EEPROM:

http://www.mouser.com/ProductDetail/Atm ... NJX6vDw%3d

The price went up by a dollar and it is back ordered for eight weeks! It also looks like is the only parallel EEPROM in that size that Mouser carries.

After I started building this parts list, I heard from Jac Goudsmit that he still had Propeedle kits available (see http://propeddle.com/ ). I have a Propeller platform board and know how to program one, and because the Propeller chip acts as the EEPROM and address decoder, its fairly flexible for experimentation. So I ordered one and we'll see if I can get it to do what. I'll need to program the Propeller to simulate a 6551, and I'll need to add a 65c22.

It does feel a little like cheating to use a 32 bit MCU to control an 8 bit microprocessor. So depending upon how the Propeedle works out I may still build a 6502 SBC, so in any event here's the updated CSV:

Title,Cat. No.,Quantity,Price Each,Total Price,Cat. URL,Notes
pin header strip,517-929647-01-36-EU,1,$2.31,$2.31,,4 1x3 + 3 1x2 pin headers
2x36 row pin header strip,649-77313-122-72LF,2,$2.29,$4.58,,2 2x3 (J1 ROM OPTS & OPT2) + 2 2x5 (JP1 & OPT1) + 4 2x7 (P-1 to P-4) + 1 2x25 (J12 Expansion Port)
.1uF,810-FK18X7R1H104K,10,$0.16,$1.60,,"c8-11, c13-c16. Using an ST 232 requires four more of these."
4.7uF,647-USP1C4R7MDD,2,$0.30,$0.60,,"c2, c3. Using an ST 232 eliminates the need for two of these."
10uF,871-B41002A4106M000,5,$0.10,$0.50,,"C1, c4, c5, c6, c12. Using an ST 232 eliminates the need for two of these."
22pF,581-SR215A220KARTR1,1,$0.19,$0.19,,c7
1.0 MHz TTL Osc,520-TCF100-X,1,$1.87,$1.87,,
1.8432MHz crystal,520-HCA184-13X,1,$1.38,$1.38,,
3.3k Ohm (3 res SIP with common),652-4604X-1LF-3.3K,1,$0.25,$0.25,,
3.3k Ohm (5 res SIP with common),71-CSC06A01-3.3K,1,$0.56,$0.56,,
W65C02S,955-W65C02S6TPG-14,1,$6.95,$6.95,,IC1
28256 EEPROM,556-AT28C25615PU,1,$9.74,$9.74,,IC2 - on backorder and only 32 KB EEPROM
62256 Static RAM,913-AS6C62256-55PCN,1,$1.79,$1.79,,IC3
74HC30,595-CD74HC30E,1,$0.44,$0.44,,IC4
74HC00,595-SN74HC00NE4,1,$0.53,$0.53,,IC5
74HC138,595-SN74HC138N,1,$0.46,$0.46,,IC6
65C51,955-W65C51N6TPG-14,1,$7.20,$7.20,,IC7
MAX232 or equivelant (e.g. ST232),700-MAX232CPE,1,$3.53,$3.53,,IC8
65C22,955-W65C22N6TPG-14,2,$6.95,$13.90,,IC9 and IC10
DS1813 or equivelant,700-DS1813-10+,1,$1.26,$1.26,,IC11
Switching Diode or strap,512-1N4148TA,3,$0.10,$0.30,,"D1, D2, D3"
LM78L05,511-L7805CV,1,$0.59,$0.59,,T1
POWER IN (user preference for part),,1,,$0.00,,
RESET switch inputs,506-MSPS103C0,1,$2.18,$2.18,,
,,,,,,
,,,total,$62.71,,

[BigDumbDinosaur]

Martin_H wrote:

@all, thanks for the suggestions. I've modified the parts list to contain the HC logic parts, and two 2x36 header pins. This reduced the price by about $4. My goal in compiling the parts list was to get a feel for the cost, and see if all the parts were available before I considered organizing a bulk order for the PCB. But I've noticed a problem with the 32 KB EEPROM:

http://www.mouser.com/ProductDetail/Atm ... NJX6vDw%3d

The price went up by a dollar and it is back ordered for eight weeks! It also looks like is the only parallel EEPROM in that size that Mouser carries.

After I started building this parts list, I heard from Jac Goudsmit that he still had Propeedle kits available (see http://propeddle.com/ ). I have a Propeller platform board and know how to program one, and because the Propeller chip acts as the EEPROM and address decoder, its fairly flexible for experimentation. So I ordered one and we'll see if I can get it to do what. I'll need to program the Propeller to simulate a 6551, and I'll need to add a 65c22.

It does feel a little like cheating to use a 32 bit MCU to control an 8 bit microprocessor. So depending upon how the Propeedle works out I may still build a 6502 SBC, so in any event here's the updated CSV:

Title,Cat. No.,Quantity,Price Each,Total Price,Cat. URL,Notes
pin header strip,517-929647-01-36-EU,1,$2.31,$2.31,,4 1x3 + 3 1x2 pin headers
2x36 row pin header strip,649-77313-122-72LF,2,$2.29,$4.58,,2 2x3 (J1 ROM OPTS & OPT2) + 2 2x5 (JP1 & OPT1) + 4 2x7 (P-1 to P-4) + 1 2x25 (J12 Expansion Port)
.1uF,810-FK18X7R1H104K,10,$0.16,$1.60,,"c8-11, c13-c16. Using an ST 232 requires four more of these."
4.7uF,647-USP1C4R7MDD,2,$0.30,$0.60,,"c2, c3. Using an ST 232 eliminates the need for two of these."
10uF,871-B41002A4106M000,5,$0.10,$0.50,,"C1, c4, c5, c6, c12. Using an ST 232 eliminates the need for two of these."
22pF,581-SR215A220KARTR1,1,$0.19,$0.19,,c7
1.0 MHz TTL Osc,520-TCF100-X,1,$1.87,$1.87,,
1.8432MHz crystal,520-HCA184-13X,1,$1.38,$1.38,,
3.3k Ohm (3 res SIP with common),652-4604X-1LF-3.3K,1,$0.25,$0.25,,
3.3k Ohm (5 res SIP with common),71-CSC06A01-3.3K,1,$0.56,$0.56,,
W65C02S,955-W65C02S6TPG-14,1,$6.95,$6.95,,IC1
28256 EEPROM,556-AT28C25615PU,1,$9.74,$9.74,,IC2 - on backorder and only 32 KB EEPROM
62256 Static RAM,913-AS6C62256-55PCN,1,$1.79,$1.79,,IC3
74HC30,595-CD74HC30E,1,$0.44,$0.44,,IC4
74HC00,595-SN74HC00NE4,1,$0.53,$0.53,,IC5
74HC138,595-SN74HC138N,1,$0.46,$0.46,,IC6
65C51,955-W65C51N6TPG-14,1,$7.20,$7.20,,IC7
MAX232 or equivelant (e.g. ST232),700-MAX232CPE,1,$3.53,$3.53,,IC8
65C22,955-W65C22N6TPG-14,2,$6.95,$13.90,,IC9 and IC10
DS1813 or equivelant,700-DS1813-10+,1,$1.26,$1.26,,IC11
Switching Diode or strap,512-1N4148TA,3,$0.10,$0.30,,"D1, D2, D3"
LM78L05,511-L7805CV,1,$0.59,$0.59,,T1
POWER IN (user preference for part),,1,,$0.00,,
RESET switch inputs,506-MSPS103C0,1,$2.18,$2.18,,
,,,,,,
,,,total,$62.71,,

I guess you didn't get the hint about using the code function to organize your list into a readable format.

BTW, you may have better luck in getting parallel EEPROMs from Jameco.

[GARTHWILSON]

BigDumbDinosaur wrote:

you may have better luck in getting parallel EEPROMs from Jameco.

250ns 32Kx8 EEPROM in 28-pin DIP, $4.95 in singles: http://www.jameco.com/webapp/wcs/stores ... 1_74878_-1
same thing in 150ns, at $5.49 in singles: http://www.jameco.com/webapp/wcs/stores ... 1_74843_-1

Jameco might be a good place to get the pin headers too. They sell a gold-plated 80-pin (2x40 cat. no. 117197) for $1.25 in singles, or a tin-plated one (cat. no. 2120284) for $0.85. For things that don't go into harsh conditions, I have never had any problem with tin-plated ones, even after they've been in service for 20+ years; so while gold plating is nice, I don't insist on it. See the pin-header catalog page at http://www.jameco.com/Jameco/catalogs/c141/P57.pdf

[Martin_H]

@Garth, thanks for the pointer.

@BigDumbDinosaur, csv's may be ugly, but they are useful because they can be pasted into the spreadsheet program of your choice, but here's my data made pretty:

Code: Select all

Title                               Mouser Cat. No.      Quan     Each      Total        Notes
———————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————
pin header strip                    517-929647-01-36-EU    1     $2.31      $2.31        4 1x3 + 3 1x2 pin headers
2x36 row pin header strip           649-77313-122-72LF     2     $2.29      $4.58        2 2x3 (J1 ROM OPTS & OPT2) + 2 2x5 (JP1 & OPT1) + 4 2x7 (P-1 to P-4) + 1 2x25 (J12 Expansion Port)
.1uF                                810-FK18X7R1H104K     10     $0.16      $1.60        "c8-11, c13-c16. Using an ST 232 requires four more of these."
4.7uF                               647-USP1C4R7MDD        2     $0.30      $0.60        "c2, c3. Using an ST 232 eliminates the need for two of these."
10uF                                871-B41002A4106M000    5     $0.10      $0.50        "C1, c4, c5, c6, c12. Using an ST 232 eliminates the need for two of these."
22pF                                581-SR215A220KARTR1    1     $0.19      $0.19        c7
1.0 MHz TTL Osc                     520-TCF100-X           1     $1.87      $1.87        
1.8432MHz crystal                   520-HCA184-13X         1     $1.38      $1.38        
3.3k Ohm (3 res SIP with common)    652-4604X-1LF-3.3K     1     $0.25      $0.25        
3.3k Ohm (5 res SIP with common)    71-CSC06A01-3.3K       1     $0.56      $0.56        
W65C02S                             955-W65C02S6TPG-14     1     $6.95      $6.95        IC1
28256 EEPROM                        556-AT28C25615PU       1     $9.74      $9.74        IC2 - on backorder and only 32 KB EEPROM
62256 Static RAM                    913-AS6C62256-55PCN    1     $1.79      $1.79        IC3
74HC30                              595-CD74HC30E          1     $0.44      $0.44        IC4
74HC00                              595-SN74HC00NE4        1     $0.53      $0.53        IC5
74HC138                             595-SN74HC138N         1     $0.46      $0.46        IC6
65C51                               955-W65C51N6TPG-14     1     $7.20      $7.20        IC7
MAX232 or equivelant (e.g. ST232)   700-MAX232CPE          1     $3.53      $3.53        IC8
65C22                               955-W65C22N6TPG-14     2     $6.95     $13.90        IC9 and IC10
DS1813 or equivelant                700-DS1813-10+         1     $1.26      $1.26        IC11
Switching Diode or strap            512-1N4148TA           3     $0.10      $0.30        "D1, D2, D3"
LM78L05                             511-L7805CV            1     $0.59      $0.59        T1
POWER IN (user preference for part)                        1     $0.00        
RESET switch inputs                 506-MSPS103C0          1     $2.18      $2.18        
                        
                                                                  total    $62.71        

[BigDumbDinosaur]

GARTHWILSON wrote:

Jameco might be a good place to get the pin headers too. They sell a gold-plated 80-pin (2x40 cat. no. 117197) for $1.25 in singles, or a tin-plated one (cat. no. 2120284) for $0.85. For things that don't go into harsh conditions, I have never had any problem with tin-plated ones, even after they've been in service for 20+ years; so while gold plating is nice, I don't insist on it.

I've never had much trouble with tinplate, provided the connector is removed and reinstalled every so often. Automobile manufacturers ran into trouble with tinplate connections back when they started to get electronics involved in engine control. We used to periodically unplug connectors while troubleshooting engine problems, just in case a flaky connection was in there. Many times, that was all that was required to get things working again. The adoption of gold plated connectors did a lot to eliminate those sorts of problems.

[RichCini]

Guys --

I'm in the process of validating an updated version of Daryl's SBC2 that I re-drew in DipTrace. I've done a 4-board prototype run because I've made a bunch of random changes to the design to enhance it a bit. Functionally, it's the same, but I did the following: added a power jack, RS232 DE9 for the console, bypass capacitors, a reset switch, a power LED and I added a Commodore-compatible IEC interface (which takes up a lot of board real estate). The board size changed to Eurocard+ (6.325" x 4") from the current size. As a trade-off, I removed the 7805 regulator and made it a 5v only board. The picture I attached is of the prototype...in the final version I shifted the power jack and compressed the board a bit.

I have some changes to EhBASIC 2.22 in order to support the IEC interface...that's what I'm working on now. Hopefully in a few weeks I can finalize the design and code and make it available. There are a few good board shops that we use in the N8VEM project that I'm going to try. For the prototypes, I used AP Circuits' $33 each service. In low production volumes, the boards are kind of expensive. I expect that the other board service will be much cheaper.

There is a description of the board on my Web site: http://www.classiccmp.org/cini/6502proj.htm

[Martin_H]

Interesting project. I like your modifications to the board. Please keep us posted because I would be interested in buying a pcb or kit if you ever make one available.

[BigDumbDinosaur]

RichCini wrote:

I'm in the process of validating an updated version of Daryl's SBC2 that I re-drew in DipTrace...

Interesting.

You could further shrink the board by using PLCC44 packages with the 65C02 and 65C22. On average, such packages use about 60 percent of the boar real estate consumed by the PDIP equivalents.

[RichCini]

BigDumbDinosaur wrote:

You could further shrink the board by using PLCC44 packages with the 65C02 and 65C22. On average, such packages use about 60 percent of the boar real estate consumed by the PDIP equivalents.

True. The N8VEM group I belong to uses the ECB format for all of their cards (100mm x 160mm), so that's what I'm familiar with and I was able to get it close with PDIP chips (I'm off by about 0.32" on the length). I did not change the ordering of the expansion buss pinout from Daryl's design.

I can tell you that I carry mostly PDIP devices in my parts bins in my shop rather than PLCC. I'm sure it would be easy, other than creating custom library parts, to make a version of the board using PLCC devices for all four 65xx chips. I wanted to keep it simple by using PDIP parts that people would more likely have in their parts bins.

Let me make the library parts for DipTrace and see what a PLCC board would look like. Thanks for the suggestion.

[floobydust]

Just a word of caution on the 65C51... your parts list is showing new stock from Mouser for the WDC part. These are the new ones with the xmit bit stuck on in the status register, i.e., they won't work with standard coding... polled or IRQ driven.

[Martin_H]

floobydust wrote:

Just a word of caution on the 65C51... your parts list is showing new stock from Mouser for the WDC part. These are the new ones with the xmit bit stuck on in the status register, i.e., they won't work with standard coding... polled or IRQ driven.

Thanks for the heads up as that strikes me as a real gotcha. Are they going to fix it or is the best course of action to buy some new old stock off eBay?

[floobydust]

Martin_H wrote:

floobydust wrote:

Just a word of caution on the 65C51... your parts list is showing new stock from Mouser for the WDC part. These are the new ones with the xmit bit stuck on in the status register, i.e., they won't work with standard coding... polled or IRQ driven.

Thanks for the heads up as that strikes me as a real gotcha. Are they going to fix it or is the best course of action to buy some new old stock off eBay?

Well, I can say they caused me some grief and some time to figure it out. Here's a post that outlines it: viewtopic.php?f=4&t=2543

As far as I know, WDC hasn't released any new chips that correct the problem. A shame.... would be nice to run at 12+ MHz, but not with 6551 parts it would seem. I have one Synertek 6551 that runs reliably at 6MHz and an AMI that's solid at 4MHz.

I'm working on fitting a SCC2691 replacement... still a ways off due to lack of free time.

[RichCini]

Just to add this slightly, based on the feedback, I'm going to work on a version of my board using PLCC for the CPU and VIAs but PDIP for the 6551. Hopefully that will free enough board real estate to accommodate an on-board SD2IEC interface.

More to come...

[RichCini]

All --

Latest board plot is attached. I added a 2x3 header for an SD2IEC device and removed the barrel-style power connector in favor of a USB Mini-B. I moved some things around but have kept it to 6.375" x 4". I'm still working on a PLCC version but DipTrace doesn't have a 44-pin PGA socket footprint -- only SMD.

The Serial IEC works fine and now I'm working on building Commodore BASIC 4.0 disk commands into BASIC itself. I've got STAT and CATALOG done. The others will be more difficult since they have string parameters.

More to come!