5.3 Upper/Lower/Critical Temperature Limit Registers (TUPPER/TLOWER/TCRIT)
The MCP9808 has a 16-bit read/write Alert Output Temperature Upper Boundary register (TUPPER), a 16-bit Lower Boundary register (TLOWER) and a 16-bit Critical Boundary register (TCRIT) that contain 11-bit data in two’s complement format (0.25°C). This data represents the maximum and minimum temperature boundary or temperature window that can be used to monitor ambient temperature. If this feature is enabled (Sensor Configuration Register (CONFIG)) and the ambient temperature exceeds the specified boundary or window, the MCP9808 asserts an Alert output. (Refer to Alert Output Configuration).
| U-0 | U-0 | U-0 | R/W-0 | R/W-0 | R/W-0 | R/W-0 | R/W-0 |
| — | — | — | Sign | 27°C | 26°C | 25°C | 24°C |
| bit 15 | bit 8 | ||||||
| R/W-0 | R/W-0 | R/W-0 | R/W-0 | R/W-0 | R/W-0 | U-0 | U-0 |
| 23°C | 22°C | 21°C | 20°C | 2-1°C | 2-2°C | — | — |
| bit 7 | bit 0 | ||||||
| R = Readable bit | W = Writable bit | U = Unimplemented bit, read as ‘0’ | |||||
| -n = Value at POR | ‘1’ = Bit is set | ‘0’ = Bit is cleared | x = Bit is unknown | ||||
| 15-13 | Unimplemented: Read as ‘0’ | ||||||
| 12 | Sign: Sign bit
| ||||||
| 11-2 | TUPPER/TLOWER/TCRIT: Temperature Boundary bits Temperature boundary trip data in two’s complement format. | ||||||
| 1-0 | Unimplemented: Read as ‘0’ | ||||||
Note: This table shows two 16-bit registers for TUPPER, TLOWER and
TCRIT, located at ‘
0000 0010b’, ‘0000 0011b’
and ‘0000 0100b’, respectively.