krischik in #hive-175254 • last yearBen Eater 6502 Kit — Day 22The interrupt requests are meant to be shared between several advanced devices. The breadboard 65C02 computer has only one of those: The 65C22 VIA (versatile interface adapter).…krischik in #hive-175254 • last yearBen Eater 6502 Kit — Day 21The 65C02 has two interrupt lines: NMI (mon maskable interrupt) and IRQ (interrupt request). It should be noted that IRQ are mend to be shared between interrupt sources (devices…krischik in #hive-175254 • last yearBen Eater 6502 Kit — Day 20The ordered spare parts have arrive and not a minute too late. The poor EEPROM looks pretty beaten: One leg broken off at the casekrischik in #hive-175254 • last yearBen Eater 6502 Kit — Day 19Up until now the computer was run either by a fairly slow 555 timer or even slower single stepping. This was possible because the WDC-65C02, unlike the R-65C02, can be run by any…krischik in #hive-175254 • last yearBen Eater 6502 Kit — Day 18As the programs become more complex debugging becomes more difficult at well. All you have are hex codes which you need to interpret yourself: . This saves integrated circuits but has a few drawbacks and quirks:krischik in #hive-175254 • last yearBen Eater 6502 Kit — Day 15The first version of the Hello World program in bare metal 65C02 assembler was 342 bytes long. That's quite a lot for such a simple assembler program. We can certainly do better.…krischik in #hive-175254 • last yearBen Eater 6502 Kit — Day 14The computer is coming along nicely. Next a Display is added to the system. Adding power . It offers parallel…krischik in #hive-175254 • last yearBen Eater 6502 Kit — Day 11Up until now the 65C02 was only supplied with NOP operation. Including the reset and interrupt vectors making the CPU start execution at EAEA₁₆ while the first addresskrischik in #hive-175254 • last yearBen Eater 6502 Kit — Day 10After I checked the CPU by hardcoding a NOP operation with 8 1kΩ resistors the next step is adding a ROM to for the future programs. Or better an EEPROM (electrical erasable…krischik in #hive-175254 • last yearBen Eater 6502 Kit — Day 9Good news. The CPU wasn't damaged after all. The RES (Reset) pin was bent inwards. To bad I didn't make a photo to show how that looked like. Anyway, with the RES not connected…krischik in #hive-175254 • last yearBen Eater 6502 Kit — Day 8It seems that the broken power supply has also destroyed the CPU itself. That's very bad and I have to order new one. Getting hold of a WDC60C02 (WDC = Western Design Center) is…krischik in #hive-175254 • last yearBen Eater 6502 Kit — Day 7One of the advantages of the WDC60C02 is the fully static design. This makes it possible to stop the CPU clock at any time without the CPU loosing its status. You can then…krischik in #hive-175254 • last yearBen Eater 6502 Kit — Day 6Sadly on day six I didn't get much done as the power supply died on me. And since I don't have another 5V, 2A power supply in my box of old power supplies I had to order a new…krischik in #hive-175254 • last yearBen Eater 6502 Kit — Day 5Day 5 and we are still building a clock. But today I finished the clock module. It was fun subproject. Tomorrow I start with the actual computer. 
