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interfaces:ds3231 [2016/04/09 13:33] darron created |
interfaces:ds3231 [2018/03/11 16:08] (current) darron [DS3231 for Pi] |
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| There are at least two RTC modules containing the | There are at least two RTC modules containing the | ||
| DS3231 available from China. Both can operate with | DS3231 available from China. Both can operate with | ||
| - | the Raspberry Pi and one is designed | + | the Raspberry Pi and one is designed |
| for it. | for it. | ||
| + | |||
| + | One useful feature of the DS3231 other than keeping | ||
| + | the time is its built-in temperature readout, however, | ||
| + | initial tests suggest that this is inaccurate. | ||
| === DS3231 for Pi === | === DS3231 for Pi === | ||
| + | |||
| + | This device is as simple as it gets. There are two pull-up | ||
| + | resistors for the I2C lines (4K3), a battery connected | ||
| + | to the VBAT pin and a capacitor on the power rails. | ||
| + | |||
| + | This device plugs directly into the GPIO header. | ||
| + | |||
| + | I bought two of these devices and one was faulty. Fixing it simply involved applying | ||
| + | pressure on each pin of the chip in turn with a hot iron, these devices may not be | ||
| + | manufactured to a high standard. | ||
| === DS3231 ZS-042 === | === DS3231 ZS-042 === | ||
| + | This module contains the RTC and an HK24C32 EEPROM. It tends | ||
| + | to ship with a CR2032 battery and, as the per | ||
| + | advice of many web sites, it's important to desolder | ||
| + | the charge feature of the module (see schematic). | ||
| + | |||
| + | By default the EEPROM content is | ||
| + | < | ||
| + | ./mcp24 1 0x57 -d | ||
| + | EEPROM FOUND AT 0x0057 | ||
| + | DUMP | ||
| + | [0000] 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 |ABCDEFGHIJKLMNOP| | ||
| + | [0010] 51 52 53 54 55 56 57 58 59 5A FF FF FF FF FF FF |QRSTUVWXYZ......| | ||
| + | </ | ||
