| ??? 09/20/08 11:50 Read: times |
#158437 - Values in the Memory Responding to: ???'s previous message |
Dear Suneet,
Time period for which a memory location holds the value depends on what kind of memory you are talking about <pre> 1> EEPROM: till you overwrites it through software (purposely or due to firmware malfunction). An accidental surge on power line may disturb some part of EEPROM till the retention period is over (given in datasheet) 2> Battery Backup RAM: till you over write through software. If battery can no longer supply sufficient current then contents will not stay 3> MCU SFR: till you or some event overwrites it(event e.g. RI sets on receiving byte on UART) Takes values given in datasheet on power on 4> DATA & on chip xDATA: till you overwrite through firmware values are not defined on power-on & retains data till device is powered. From my experience it retains this data if reset is not through poweron. (e.g. during execution, just tie reset with vcc momentory, & let device restart execution, if there is no initialisation to this memory you can see same contents of DATA) 5> off-chip RAM without battery backup: till you overwrite through firmware. retains value as long as powered. Regards, Mahesh |
| Topic | Author | Date |
| are values stored in memory permanent ? | 01/01/70 00:00 | |
| Depends on memory | 01/01/70 00:00 | |
| I A P | 01/01/70 00:00 | |
| could you help me with the IC | 01/01/70 00:00 | |
| serial EEPROM | 01/01/70 00:00 | |
| serial EEPROM with SPI also possible | 01/01/70 00:00 | |
| I have my doubts... | 01/01/70 00:00 | |
| I2C takes some reading to implement | 01/01/70 00:00 | |
| that's the point | 01/01/70 00:00 | |
| Values in the Memory | 01/01/70 00:00 | |
| a caveat | 01/01/70 00:00 | |
| RE: a caveat | 01/01/70 00:00 | |
| Any assemblers? | 01/01/70 00:00 | |
| As long as others are all being strictly technical | 01/01/70 00:00 | |
C standard | 01/01/70 00:00 | |
| Another caveat | 01/01/70 00:00 | |
| sorry for the delay | 01/01/70 00:00 | |
| which? | 01/01/70 00:00 | |
| Maxim too has One-wire EEPROMs | 01/01/70 00:00 |