| ??? 12/30/04 17:31 Read: times |
#84129 - NVSRAM+WD Responding to: ???'s previous message |
If for some reason you'd need some external non-volatile R/W memory (i.e. for logging the readouts) you may try the BQ... series NVSRAM from Texas Instruments (i.e. BQ4832Y). They come with a lot of features that are useful in a microcontroller.
* Integrated SRAM, real-time clock, CPU supervisor, crystal, power-fail circuit, and battery * Real-Time Clock counts hundredths of seconds through years in BCD format * RAM-like clock access * Compatible with industry-standard 32K x 8 SRAMs * Unlimited write cycles * 10-year minimum data retention and clock operation in the absence of power * Automatic power-fail chip deselect and write-protection * Watchdog timer, power-on reset, alarm/periodic interrupt, power-fail and battery-low warning * Software clock calibration for greater than ±1 minute per month accuracy If such a controller is meant to be a standalone battery-powered device logging some external data, such a chip is very valuable as it provides some essentials and some handy things: - ability to wake up periodically through alarm (huge battery savings) - power on reset - reliable and healthy power-up each time the device "wakes up". - watchdog timer - important for reliablity when working - RTC - to timestamp readouts. - reliable storage for results. Of course if the device you create is to send results to something else as soon as it reads them, without much worry about saving power and keeping old values, the above isn't as useful anymore :) |
| Topic | Author | Date |
| Alternative ICs wanted | 01/01/70 00:00 | |
| Re.: Alternative ICs wanted | 01/01/70 00:00 | |
| Watchdog + Reset generator | 01/01/70 00:00 | |
| NVSRAM+WD | 01/01/70 00:00 | |
| Good Reply. | 01/01/70 00:00 | |
Often a FET-OPamp is needed | 01/01/70 00:00 | |
| WatchDogTimer made using 14538 ic | 01/01/70 00:00 | |
| alternatives | 01/01/70 00:00 |