my build is based off of a 16-bit ISA backplane, with a Arduino Mega2560 clone for the MCU.
![20230502_122743.jpg 20230502_122743.jpg](https://www.tjfhome.net/community/data/attachments/0/40-40d1c8312c60c73ecb387ee58eb1cb6f.jpg?hash=QNHIMSxgxz)
![20230502_122754.jpg 20230502_122754.jpg](https://www.tjfhome.net/community/data/attachments/0/41-bc22398bac810e0473bfdb89e70b9c57.jpg?hash=vCI5i6yBDg)
![20230502_122805.jpg 20230502_122805.jpg](https://www.tjfhome.net/community/data/attachments/0/42-3109526008b164bc3cddf995ad368368.jpg?hash=MQlSYAixZL)
in the third image, you can see my UP3593 on the "test track".
also note, these images are from a while back, and my workbench has become quite a bit more cluttered as of late.
the plan with the ISA back-plane, is to connect the I2C and SPI bus pins to it, and allow easier expansion. so far, i have just the one card, so it looks rather "over engineered". while the main-board and back-plane are 16-bit, i have only found 8-bit ISA prototyping boards available, so i will have to limit it to just those bus rails. my original plan was to have a separate card for the Ethernet adapter, motor-shields, and GPIO expansion. then i built that hodge-podge mess above... though once the SPI and I2C are routed to the ISA bus, it would be simple to move the Ethernet to a card. i would just need to also add the support pins, like chip-select and interrupts. i think i should also route the reset pin to the ISA as well.
the EX_FastClock project could also be moved to it's own project, with the serial connection in place. as the EX_FastClock uses just one-way serial, i think, it could just be connected via a RS485 connection for distance.
the initial plan for GPIO was for on-board, or on-card, MCP23017 chips to expand the GPIO. this will be fine. and as for turnout control, i was going to use servos, controlled locally, but now i am thinking of making remote modules that take a digital signal, and change it to either slipper-motor (tortoise) control, or servo control. but it can be done easily with a smaller MCU. but the smaller MCU ca be positioned local to the action to e performed.
as far as power supplies, i think i currently use an ATX power-supply, but i am leaning more toward a single big power supply, set for 15V, with fuse blocks to distribute power, and DC-to-DC converters to drop the voltage from the main PSU down to needed levels. in theory this should work... i have no idea if the big PSU is double-shielded, or not. but i hope to figure out some circuit protection to shutdown the power if it surges at all. maybe a crowbar circuit of sorts. after-all, the big PSU is rated for some fair amps. ...or i could just wing it, as i usualy do, and throw caution to the wind...![Roll eyes :rolleyes: :rolleyes:](https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f644.png)
the big PSU can supply 100A at up to 15Vdc. it is a RV power converter. it will be using a grounded outlet, so the frame will be grounded. i can't get high enough current to supply everything by using 400 different power blocks. i don't have that kind of funds.
now, the PSU will likely not have very clean power, but i can filter it a bit, and then filter it more in my circuits. even though last time i checked the PSU, it really wasn't that bad, noise-wise. but a little extra filtering can't hurt. that way i know my track signals are good and clean. even just tossing in some filter caps may be enough, compaired to what i used before, that worked just fine...
i could easily connect my oscilliscope to the PSU and see how noisy it is...
Now, the question remains on how to mount the whole contraption... i have a small AV rack i built that i could make use of. just have to make sure it has ventalation for PSU cooling. the front door is currently hollow so i could put a Lexan window in it, but i may just install a 1/4in or 3/8in panel to mount the LCD, some status LEDs, power switch, and so forth. the back panel will be removable for access. i think i even still have the original back panel. the back will contain the track wiring connectors, and maybe some other connections, as needed. don't know yet.
![20230502_122743.jpg 20230502_122743.jpg](https://www.tjfhome.net/community/data/attachments/0/40-40d1c8312c60c73ecb387ee58eb1cb6f.jpg?hash=QNHIMSxgxz)
![20230502_122754.jpg 20230502_122754.jpg](https://www.tjfhome.net/community/data/attachments/0/41-bc22398bac810e0473bfdb89e70b9c57.jpg?hash=vCI5i6yBDg)
![20230502_122805.jpg 20230502_122805.jpg](https://www.tjfhome.net/community/data/attachments/0/42-3109526008b164bc3cddf995ad368368.jpg?hash=MQlSYAixZL)
in the third image, you can see my UP3593 on the "test track".
also note, these images are from a while back, and my workbench has become quite a bit more cluttered as of late.
the plan with the ISA back-plane, is to connect the I2C and SPI bus pins to it, and allow easier expansion. so far, i have just the one card, so it looks rather "over engineered". while the main-board and back-plane are 16-bit, i have only found 8-bit ISA prototyping boards available, so i will have to limit it to just those bus rails. my original plan was to have a separate card for the Ethernet adapter, motor-shields, and GPIO expansion. then i built that hodge-podge mess above... though once the SPI and I2C are routed to the ISA bus, it would be simple to move the Ethernet to a card. i would just need to also add the support pins, like chip-select and interrupts. i think i should also route the reset pin to the ISA as well.
the EX_FastClock project could also be moved to it's own project, with the serial connection in place. as the EX_FastClock uses just one-way serial, i think, it could just be connected via a RS485 connection for distance.
the initial plan for GPIO was for on-board, or on-card, MCP23017 chips to expand the GPIO. this will be fine. and as for turnout control, i was going to use servos, controlled locally, but now i am thinking of making remote modules that take a digital signal, and change it to either slipper-motor (tortoise) control, or servo control. but it can be done easily with a smaller MCU. but the smaller MCU ca be positioned local to the action to e performed.
as far as power supplies, i think i currently use an ATX power-supply, but i am leaning more toward a single big power supply, set for 15V, with fuse blocks to distribute power, and DC-to-DC converters to drop the voltage from the main PSU down to needed levels. in theory this should work... i have no idea if the big PSU is double-shielded, or not. but i hope to figure out some circuit protection to shutdown the power if it surges at all. maybe a crowbar circuit of sorts. after-all, the big PSU is rated for some fair amps. ...or i could just wing it, as i usualy do, and throw caution to the wind...
![Roll eyes :rolleyes: :rolleyes:](https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f644.png)
the big PSU can supply 100A at up to 15Vdc. it is a RV power converter. it will be using a grounded outlet, so the frame will be grounded. i can't get high enough current to supply everything by using 400 different power blocks. i don't have that kind of funds.
now, the PSU will likely not have very clean power, but i can filter it a bit, and then filter it more in my circuits. even though last time i checked the PSU, it really wasn't that bad, noise-wise. but a little extra filtering can't hurt. that way i know my track signals are good and clean. even just tossing in some filter caps may be enough, compaired to what i used before, that worked just fine...
i could easily connect my oscilliscope to the PSU and see how noisy it is...
Now, the question remains on how to mount the whole contraption... i have a small AV rack i built that i could make use of. just have to make sure it has ventalation for PSU cooling. the front door is currently hollow so i could put a Lexan window in it, but i may just install a 1/4in or 3/8in panel to mount the LCD, some status LEDs, power switch, and so forth. the back panel will be removable for access. i think i even still have the original back panel. the back will contain the track wiring connectors, and maybe some other connections, as needed. don't know yet.