DR240 Non-volatile memory
The DR240 has 6 types of non-volatile memory, all of which are retained when power fails. None of them rely on the RTC battery. Here's an overview:
| Storage Area | Size | Preload | Erased | Writable | Non-Volatile | UsesRAM | Status Returned | Endurance |
|---|
| Permanent Memory | 13 | No | Yes | Yes | Yes | Yes | Yes | 2.5 million |
| Shadow | 250 | No | No | Yes | Yes | Yes | No | 320,000 |
| NVEM0 | 64k(*1) | Yes | Replaced | No | Yes | No | N/A | N/A |
| NVEM1 | 248 | No | No | Yes | Yes | No | No | 320,000 |
| NVEM2 | 64K | No | No | Yes | No | No | No | Infinite |
| NVEM3 | 4K | No | No | | No | No | No | Infinite |
Where:
- Size:
This is the size of the non-volatile area in bytes. - Preload:
Indicates whether your source code can hold data that SPLat/PC can compile and download into the storage area. - Erased:
Indicates what happens to the storage area when a new application is downloaded to the controller. - Writable:
Indicates whether your running application can write to the storage area. A "No" would mean only SPLat/PC can during "Preload". - Non-Volatile
Whether contents are saved when power is removed. - UsesRAM:
Indicates if reading or writing to the storage area occurs to/from RAM. - Status Returned:
Indicates if the area returns status information when it is read. - Endurance:
Guaranteed minimum number of erase/write cycles. Reading has no limit.
*1: NVEM0 space is shared with your application. The combined size of both is limited to 64kB.