USE STM Internal RTC | https://embedded-lab.com/blog/stm32s-internal-rtc/ |
Atmel RTC calibration appnote | https://ww1.microchip.com/downloads/en/Appnotes/Atmel-42251-RTC-Calibration-and-Compensation_AP-Note_AT03155.pdf |
Т=(U*C)/I
где:
Даже если ток 1 мкА и напряжение 1 В при 1 Фараде получится 1000000 секунд= почти 12 суток
Page | P/N | Manufacturer | Photo | Description | Type | Kind | Vin min | Vin max | Current | Case | Links | IT | marking | p2p group | note | ↑ price | temprange | stability | interface | eeprom |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
rv-3032-c7 | RV-3032-C7 | Micro-Crystal | IC-FREQ-RTC | IC | RTC | 1.3 | 5.5 | link | int xtal | 1.98$ (при заказе 3000 шт.) | -40...+85C | 2.5ppm | ||||||||
ins5699c | INS5699C | DaPu | IC-FREQ-RTC | IC | RTC | 1.6 | 5.5 | SMD3225 | TCXO | 1.49$ (при заказе 3000 шт.) | -40...+85C | 3.4ppm | I2C | |||||||
ins5699s | INS5699S | DaPu | IC-FREQ-RTC | IC | RTC | 2.5 | 5.5 | SMD3225 | TCXO | 1.298$ (при заказе 3000 шт.) | -40...+85C | 5ppm | I2C | |||||||
ins5101a | INS5101A | DaPu | IC-FREQ-RTC | IC | RTC | SOIC8 | I2C | |||||||||||||
ds1302z | DS1302Z | JSMICRO | IC-FREQ-RTC | IC | RTC | 2 | 5.5 | 300nA | SOIC8 | link | trickle-charger | 0...+70C | 3WIRE (SPI) | 31x8 | ||||||
ds1307zm_tr | DS1307ZM/TR | HGSEMI | IC-FREQ-RTC | IC | RTC | 5 | 5 | 500nA | SOIC8 | I2C | 56x8 | |||||||||
pcf8523tk_1_118 | PCF8523TK/1,118 | NXP | IC-FREQ-RTC | IC | RTC | 150nA | I2C | |||||||||||||
ds3231mz | DS3231MZ+ | Maxim | IC-FREQ-RTC | IC | RTC | 150nA | SOIC8 | 5ppm | I2C | |||||||||||
bl5372 | BL5372 | Belling | IC-FREQ-RTC | IC | RTC | 1.8 | 5.5 | 400nA | SOIC8 | link | I2C | |||||||||
tr8804 | TR8804 | TKD | IC-FREQ-RTC | IC | RTC | 1.65 | 5.5 | link | int xtal |
BL5372 - аналог Dallas DS1337, однако I2C обмен отличается.
Пример регистров на BL5372:
Особенность адресации внутренних регистров состоит в том, что под адрес выделено 4 старших бита в байте.
0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef 00: 02 02 02 02 XX XX XX XX 02 02 02 02 XX XX XX XX ????XXXX????XXXX 10: 13 13 13 13 XX XX XX XX 13 13 13 13 XX XX XX XX ????XXXX????XXXX 20: 29 29 29 29 XX XX XX XX 29 29 29 29 XX XX XX XX ))))XXXX))))XXXX 30: 05 05 05 05 XX XX XX XX 05 05 05 05 XX XX XX XX ????XXXX????XXXX 40: 01 01 01 01 XX XX XX XX 01 01 01 01 XX XX XX XX ????XXXX????XXXX 50: 11 11 11 11 XX XX XX XX 11 11 11 11 XX XX XX XX ????XXXX????XXXX 60: 0c 0c 0c 0c XX XX XX XX 0c 0c 0c 0c XX XX XX XX ????XXXX????XXXX 70: 00 00 00 00 XX XX XX XX 00 00 00 00 XX XX XX XX ....XXXX....XXXX 80: 00 00 00 00 XX XX XX XX 00 00 00 00 XX XX XX XX ....XXXX....XXXX 90: 04 04 04 04 XX XX XX XX 04 04 04 04 XX XX XX XX ????XXXX????XXXX a0: 40 40 40 40 XX XX XX XX 40 40 40 40 XX XX XX XX @@@@XXXX@@@@XXXX b0: 00 00 00 00 XX XX XX XX 00 00 00 00 XX XX XX XX ....XXXX....XXXX c0: 00 00 00 00 XX XX XX XX 00 00 00 00 XX XX XX XX ....XXXX....XXXX d0: 00 00 00 00 XX XX XX XX 00 00 00 00 XX XX XX XX ....XXXX....XXXX e0: 00 00 00 00 XX XX XX XX 00 00 00 00 XX XX XX XX ....XXXX....XXXX f0: 10 10 10 10 XX XX XX XX 10 10 10 10 XX XX XX XX ????XXXX????XXXX
C115=C116, pF | Частота, Hz |
---|---|
нет | 32772 |
10pF | 32769 |
12pF | 32769 |
Clock operating voltage: 1.0 V to 5.5 V
Vth(sw)bat is the battery switch threshold voltage. Typical value is 2.5 V.
When VBAT drops below the threshold value Vth(bat)low (typically 2.5 V), the BLF flag (register Control_3) is set to indicate that the battery is low and that it must be replaced.
VBAT battery supply voltage power management function active 1.8 - 5.5 V
Vth(sw)bat battery switch threshold voltage 2.1 2.5 2.7 V