Comparison

SchemaHD vs SDK85

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

SchemaHD

This app allows users to draw circuit diagrams for logic circuits, generating Verilog HDL and performing simulations. It simplifies FPGA development by using schematics instead of complex programming languages, offering advanced security and high-performance parallel processing.

Highlights
  • Draw logic circuit diagrams
  • Generate Verilog HDL
  • Perform circuit simulations
  • Touch-based wiring
  • AXI bus interface support
  • JSON import/export
  • Offline network operation
Features
Read full description

FPGAs can dynamically generate logic circuits by means of configuration bit streams generated by languages such as Verilog and VHDL. The generated logic circuit cannot be changed by communication data. Therefore, it is very safe and cannot be attacked by hacking, which is a problem with CPUs, to execute arbitrary commands. In addition, the generated logic circuits are all running simultaneously, so the highest performance parallel processing is being performed. It can also generate logic circuits using configuration bitstreams at very high speed. Most of the processing that can be done by the CPU can be done by the FPGA alone. With advanced security and the highest performace, FPGAs are the perfect device for the modern age. However, it takes a lot of effort to learn languages such as Verilog and VHDL. There are other methods such as high-level synthesis from C/C++, but they require a lot of adjustments such as #pragma, and do not maximize the capabilities of the FPGA. Schematics, not programming languages, are needed to maximize the capabilities of FPGAs and to further improve developer productivity. Schematics allow you to grasp the whole picture at a glance, and can perfectly represent parallel processing. SchemaHD is to draw a circuit diagram of a logic circuit, and it's possible to do generation of Verilog HDL and a simulation. A made circuit diagram can be used by a different circuit diagram immediately. You can also install wiring easily by touch operation. A concept of interface is adopted as a terminal, so something structured of a AXI bus can also be used. A terminal it's also possible to distinguish sound argument reason, negative logic and characteristic wiring of a clock and a reset by interface, and which is different in interface, they don't seem able to connect, it is. You can input and output as a JSON file, so the made circuit diagram and interface are also capable of cooperation with other application. Verilog HDL generated from a circuit diagram contains a comment of a terminal name and an instance name, so it's capable of the correspondence which is at the time of problem occurrence. A network connection isn't needed, so it's also effective in information leak prevention. A simple simulation is offered in the present, but it's expected to enhance it early.

About

SDK85

This app emulates the Intel SDK-85 System Design Kit, allowing users to program and execute 8085 machine code. It features a hexpad, seven-segment display, and a monitor program, with an optional TTY mode for more comfortable input.

Highlights
  • 8085 microprocessor emulation
  • Hexpad and seven-segment display UI
  • Monitor program for code entry/execution
  • TTY mode for serial terminal input
  • Code execution suspension to save battery
  • Play/pause button for resuming execution
Features
Read full description

An emulator of the SDK-85 System Design Kit issued by Intel in the mid-seventies. The kit featured an 8085 micro processor, some basic IO chips, and a UI comprised of a hexpad and a six-digit seven-segment display. There was also a ROM plugged onto the board which contained a monitor program to enter and execute machine code on the 8085. The app emulates an 8085 and executes the monitor (shippment granted by Intel as long as the app is free and educational). The original kit leveraged the serial IO pins of the 8085 to connect a TTY as a somewhat more comfortable alternative to the hexpad/ display UI used by the monitor on startup. A wipe-left gesture shifts in a simple terminal and the monitor switches to TTY mode. To use the app one needs to get a copy of the original SDK-85 System Design Kit User‘s Manual (ask Google) and work it thru. Some knowledge of the 8085 and its instruction set is helpful as well, and being a boomer nerd who loved to program micro computers when young (and still does) is key. Intel designed the monitor to run in a loop that keeps the CPU constantly busy (on a single thread). To prevent the battery from draining the app suspends executing after 15 seconds indicated by a slightly blurred display. Tapping the centered play-pause button resumes the monitor or any other program in execution. Timeout and a few other options can be changed in the app‘s entry in Settings.

Screenshots

SDK854 screens

Verdict

The call

The clearest difference is rating: SDK85 at 4.0 against SchemaHD's 3.0. SDK85 also leads on in-app purchases (none vs 7). SchemaHD's advantage is iOS requirement (14.0 vs 17.0). On price, ratings volume, update cadence and ads there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. SchemaHD sells 7 one-off in-app purchases. SDK85 asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

SDK85 holds the better App Store score, 4.0 against 3.0. Both are backed by a comparable volume of ratings — 2 and 1 respectively.

UpkeepUpdate frequency

SchemaHD ships an update every 10 days, SDK85 every 2 weeks. The most recent releases landed on June 6, 2026 and September 18, 2026 respectively.

Scorecard3 real differences · 7 level
SchemaHD versus SDK85: the parameters behind the verdict, then further details
ParameterSchemaHDSDK85
PriceFreeFree
Rating3.0 (2 ratings)4.0 (1 ratings) — better
Positive reviews50.0% of reviews—
Number of ratings2 — better1
Update frequencyEvery 10 days — betterEvery 2 weeks
AdsNoNo
In-app purchasesYesNo — better
MonetizationFreeFree
DevicesiPadiPhone, iPad — better
Requires iOS14.0 — better17.0
Further details — not scored
Size2 MB12 MB
Age rating4+4+
DeveloperYasuaki IwasakiJuergen Schuck

Customer experience

SchemaHD

All ratings2 ratings
Positive50.0%
Neutral0.0%
Negative50.0%
Written reviews2 reviews
Positive50.0%
Neutral0.0%
Negative50.0%

SDK85

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

7 purchases

SchemaHD

One-time7
  • Give a tip #1$1.99
  • Give a tip #2$3.99
  • Give a tip #3$7.99
Show 4 more
  • Give a tip #4$15.99
  • Give a tip #5$23.99
  • Give a tip #6$39.99
  • Give a tip #7$79.99
None

SDK85

No in-app purchases

Questions

Is SchemaHD free?
SchemaHD is free to download, with in-app purchases available.
Is SDK85 free?
SDK85 is free to download, with no in-app purchases.
Which has better reviews, SchemaHD or SDK85?
SDK85 is rated higher. SchemaHD averages 3.0 out of 5 from 2 ratings, while SDK85 averages 4.0 from 1 ratings.
Do SchemaHD or SDK85 have ads?
Neither SchemaHD nor SDK85 shows ads.
Which is updated more often, SchemaHD or SDK85?
SchemaHD ships an update every 10 days, and SDK85 every 2 weeks. Most recently, SchemaHD was updated on June 6, 2026 and SDK85 on September 18, 2026.

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