The instruction
SPxPoll1 1,!CPU
will return a single byte in U0 that indicates various things:
| Bit | Signifies |
| 0 | RTC hardware present (D>=16) |
| 1 | Unused |
| 2 | Unused |
| 3 | Unused |
| 4 | Unused |
| 5 | Unused |
| 6 | Unused |
| 7 | Unused |
Note: Not all bits are relevant to all products and/or dialects.