RTC thoughts
Posted: 16 Dec 2018 11:39
I've had it in mind for a while to use my RTC modules ( falcon) on the next board. The problem is it will need a pld to take care of the address decoding.
It would be (possibly) easier to add on the new booster design, but there isn't any room for starters. Plus the I don't want to force people to buy the boosterr to get the addons.
I can only think that having a pld under the dip 68000 like on the sec booster would be the way to do it. Pretty much that pld could do tos206 decoding , manage the ide port and rtc. Of course firmware for ide and rtc isn't done, but having the pld on board wired up ready can't hurt.
I could also make provisions for the "doubleST" booster logic. The idea is to just have some io pads as a breakout for the pld. Then as clock lines go via resistors, jumper wires can be added to the pld to do the mods.
Now I could route all the signals via the pld anyway, but if something goes wrong somewhere then it will cause problems. Not everyone may want to solder the pld for those features and not everyone has a programmer.
In some cases this pld would be better on its own expansion header. So I can program the chips for people , but of course its another io board I will have to design. So its not a ideal solution.
Altrea programmers are cheaper, and while I have run my ste booster on a alters chip, its a lot more work for me to convert to a new pld. So not ideal either.
The atmel programmers are about £60 , so not massive costs anyway. The sec booster uses atmel as well.
I'm thinking out loud mostly. I think adding the pld under the dip68000 socket is the way to go. With using a few jumper wires the old can be wired in that way. Then the pld isnt needed to get the board running as a stock machine either. I can make the rtc board and ide header on the motherboard and wire it to the pld ready, then work out the firmware another day.
It would be (possibly) easier to add on the new booster design, but there isn't any room for starters. Plus the I don't want to force people to buy the boosterr to get the addons.
I can only think that having a pld under the dip 68000 like on the sec booster would be the way to do it. Pretty much that pld could do tos206 decoding , manage the ide port and rtc. Of course firmware for ide and rtc isn't done, but having the pld on board wired up ready can't hurt.
I could also make provisions for the "doubleST" booster logic. The idea is to just have some io pads as a breakout for the pld. Then as clock lines go via resistors, jumper wires can be added to the pld to do the mods.
Now I could route all the signals via the pld anyway, but if something goes wrong somewhere then it will cause problems. Not everyone may want to solder the pld for those features and not everyone has a programmer.
In some cases this pld would be better on its own expansion header. So I can program the chips for people , but of course its another io board I will have to design. So its not a ideal solution.
Altrea programmers are cheaper, and while I have run my ste booster on a alters chip, its a lot more work for me to convert to a new pld. So not ideal either.
The atmel programmers are about £60 , so not massive costs anyway. The sec booster uses atmel as well.
I'm thinking out loud mostly. I think adding the pld under the dip68000 socket is the way to go. With using a few jumper wires the old can be wired in that way. Then the pld isnt needed to get the board running as a stock machine either. I can make the rtc board and ide header on the motherboard and wire it to the pld ready, then work out the firmware another day.