Search found 4 matches

by DarthWader
Sun Nov 10, 2019 1:37 pm
Forum: GBDev
Topic: Latching the Real Time Clock (RTC) in MBC3
Replies: 13
Views: 4204

Re: Latching the Real Time Clock (RTC) in MBC3

Well here is the VHDL I've made so far. I have no idea if the RTC code will work at all, since I still need to buy a chip with enough macrocells to fit it. It will be a while before I can try it out, so if anyone wants to test/optimize/play with it, feel free. An oscillator will be required to gener...
by DarthWader
Sat Nov 09, 2019 3:08 pm
Forum: GBDev
Topic: Latching the Real Time Clock (RTC) in MBC3
Replies: 13
Views: 4204

Re: Latching the Real Time Clock (RTC) in MBC3

How about retries... 1st cycle, incremented=false 2nd cycle, do latching 3rd cycle, need_retry=incremented 4th cycle, if need_retry then do_latching Something like that, the separate 3rd and 4th cycle should make sure that an increment flag change won't occur together with the retry. Or, copy the t...
by DarthWader
Sat Nov 09, 2019 1:18 pm
Forum: GBDev
Topic: Latching the Real Time Clock (RTC) in MBC3
Replies: 13
Views: 4204

Re: Latching the Real Time Clock (RTC) in MBC3

Would it not be easier to just use a dedicated RTC chip (something like this ) and relay that info back to the CPLD/FPGA when the console needs it? Keeps power consumption from the CPLD away from the battery. That was actually my first plan, using a calendar RTC chip with a parallel interface. The ...
by DarthWader
Fri Nov 08, 2019 8:38 pm
Forum: GBDev
Topic: Latching the Real Time Clock (RTC) in MBC3
Replies: 13
Views: 4204

Latching the Real Time Clock (RTC) in MBC3

Hey guys, new user here. I'm working on a VHDL implementation of the MBC3, with RTC. Everything's going great, it plays games just fine, but I'm struggling to read the RTC data. I understand what the wiki says: [b]6000-7FFF - Latch Clock Data (Write Only)[/b] When writing 00h, and then 01h to this r...