Building a HP35 scientific calculator clone - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: Not HP Calculators (/forum-7.html) +--- Forum: Not quite HP Calculators - but related (/forum-8.html) +--- Thread: Building a HP35 scientific calculator clone (/thread-18544.html)

Building a HP35 scientific calculator clone - olekgr - 07-10-2022 11:31 AM It's nice to present this project - Building a HP35 scientific calculator clone with a Z80 cpu from scratch. But without using emulators, HP microcode etc. I have always wanted to rewrite original algorithms, created by David S. Cochran. As the original HP35 was built 50 years ago, this is a good time to do the same :-) Everything (hardware, software, source code, working gerbers etc) is on my github page: https://github.com/olekgr/HP-35_Z80 I hope this project will be interesting for someone. RE: Building a HP35 scientific calculator clone - EdS2 - 07-11-2022 07:33 AM Very nice! Thanks for sharing your code too! RE: Building a HP35 scientific calculator clone - Roland57 - 07-11-2022 08:25 AM Great job, especially using the original algorithms !! Does your hp35 even exhibit the ln 2.02 bug ? :-) Roland RE: Building a HP35 scientific calculator clone - Chr Yoko - 07-11-2022 03:42 PM Great work ! So you programmed the whole simulator under Z80 assembly language 8-) (8 bits) Looking at your schematic , it is quite inspiring too. RE: Building a HP35 scientific calculator clone - redglyph - 07-11-2022 07:58 PM That's impressive, thanks for sharing! My first reflex would be indeed to use an FPGA, but it's not as fun as using the real Z80 and logic ICs. I used to love this CPU assembly language! RE: Building a HP35 scientific calculator clone - Required - 07-14-2022 07:43 AM Wow. Great work. Love the assembly - reminds me of the coding I did as young. Thank you for sharing! RE: Building a HP35 scientific calculator clone - eshazen - 07-10-2023 11:06 PM Very nice! I also built an HP-25 replica using a Z80 but I run the HP microcode in a C emulator. Your software is much more impressive. My project: https://github.com/eshazen/retro-25