[Coco] Battery-Backed RTCs for CoCo?

[Dave Philipsen]

Actually we have a NitrOS9 driver for the newer (and cheaper) DS3231 
chip that is so prevalent on many RTC boards available on eBay.  It is 
currently used on the CoCo3FPGA.  I believe that the general register 
architecture of the Dallas Semi chips are all pretty much the same.  
It's just that the older ones were accessed in a slightly different way 
before the advent of I2C and SPI.

Dave


On 11/30/2018 2:24 PM, RETRO Innovations wrote:
> On 11/30/2018 9:34 AM, Robert Gault wrote:
>> Jim,
>>
>> Can't say much about relative cost of the RTCs 
> Well, it's not cost per se, but compatibility.  The cheaper RTCs needs 
> new drivers, as they are not compatible with the DS1315 and the DS1216
>> but there is no reason to worry about IRQ problems. There is no need 
>> to update the OS-9 time frequently. Just always use the clock_soft 
>> module and run a separate program to read the RTC say every 10 minutes.
>>
>> I have my NitrOS-9 set this way and even though a 9 byte initialize 
>> code must be sent to my RTC for each read, no significant time is lost.
>
> Gene Heskett.  Care to weigh in?
>
> For reference, here was the original concern:
>
> On 11/10/2018 9:05 PM, Gene Heskett wrote:
>> The one in the B&B is fairly good, but its security password has to be
>> clocked into it a bit at a time from an $AA55 integer.  And it has to be
>> done while all interrupts are disabled. And having the IRQ's locked out
>> for so long absolutely trashes the bitbanger if its in use, and renders
>> the deluxe rs232 pack workless above around 300 baud from frameing
>> overruns. I worked on that clock module too, but it screwed up so many
>> file transfers I bought the disto 4&1 & went scsi.
>