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Description
Maxim DS1307 Real Time Clock Driver unit
The Maxim DS1307 is an I2C interface, battery backed real time clock chip with full BCD clock and calendar and 56 bytes of software accessible NVRAM. The chip supports 12 or 24 hour format and is widely used in low cost RTC devices available from a range of suppliers.
This driver extends the real time clock API to include functions for directly reading and writing the NVRAM which could be used for storing device specific information and configuration or for non volatile storage of keys, passwords or tokens.
Constants
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DS1307 specific constants DS1307_*
DS1307_RTC_DESCRIPTION = 'Maxim DS1307 Real Time Clock';
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Description of DS1307 device
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DS1307_MIN_TIME = 125911584000000000;
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Time starts at 01/01/2000 00:00:00 (MM/DD/YY HH:MM:SS)
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DS1307_MAX_TIME = 157469183990000000;
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Time ends at 12/31/2099 23:59:59 (MM/DD/YY HH:MM:SS)
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DS1307 chip constants DS1307_CHIP_*
DS1307_CHIP_DS1307 = 0;
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DS1307_CHIP_DS1337 = 1;
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DS1307_CHIP_DS1338 = 2;
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DS1307_CHIP_DS1339 = 3;
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DS1307_CHIP_DS1340 = 4;
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DS1307_CHIP_DS1388 = 5;
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DS1307_CHIP_DS3231 = 6;
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DS1307_CHIP_M41T00 = 7;
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DS1307_CHIP_MCP794XX = 8;
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DS1307_CHIP_RX8025 = 9;
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DS1307 RTC register constants DS1307_REG_*
DS1307_REG_SECONDS = $00;
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00-59
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DS1307_REG_MINUTE = $01;
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00-59
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DS1307_REG_HOUR = $02;
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00-23 (or 1-12am,pm)
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DS1307_REG_WEEKDAY = $03;
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01-07
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DS1307_REG_DAY = $04;
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01-31
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DS1307_REG_MONTH = $05;
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01-12
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DS1307_REG_YEAR = $06;
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00-99
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DS1307 control and status register constants DS1307_REG_*
DS1307_REG_CONTROL = $07;
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Also DS1338
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DS1337_REG_CONTROL = $0e;
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DS1340_REG_CONTROL = $07;
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DS1340_REG_FLAG = $09;
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DS1337_REG_STATUS = $0f;
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DS1339_REG_ALARM1_SECONDS = $07;
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RX8025_REG_CONTROL1 = $0e;
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RX8025_REG_CONTROL2 = $0f;
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[Expand]
DS1307 seconds register constants DS1307_REG_SECONDS_*
DS1307_REG_SECONDS_CH = $80;
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Clock Halt bit (1 to Disable / 0 to Enable the clock)
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DS1340_REG_SECONDS_nEOSC = $80;
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MCP794XX_REG_SECONDS_ST = $80;
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Clock Stop Bit (1 to Enable / 0 to Disable the clock)
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[Expand]
DS1307 hour register constants DS1307_REG_HOUR_*
DS1307_REG_HOUR_12HR = $40;
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12/24 hour bit (1 = 12 hour mode / 0 = 24 hour mode)
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DS1307_REG_HOUR_PM = $20;
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AM/PM bit (1 = PM / 0 = AM) (Only in 12 hour mode)
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DS1340_REG_HOUR_CENTURY_EN = $80;
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DS1340_REG_HOUR_CENTURY = $40;
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[Expand]
MCP794XX weekday register constants MCP794XX_REG_WEEKDAY_*
MCP794XX_REG_WEEKDAY_VBATEN = $08;
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Battery Backup Enabled (1 to Enable / 0 to Disable)
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[Expand]
DS1337 month register constants DS1337_REG_MONTH_*
DS1337_REG_MONTH_CENTURY = $80;
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[Expand]
DS1307 control register constants DS1307_REG_CONTROL_*
DS1307_REG_CONTROL_OUT = $80;
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Output Control (Output level of SQW/OUT pin when SQWE = 0)
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DS1338_REG_CONTROL_OSF = $20;
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DS1307_REG_CONTROL_SQWE = $10;
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Square-Wave Enable (When set to 1, enables the oscillator output)
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DS1307_REG_CONTROL_RS1 = $02;
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Rate Select 1 (See datasheet for values)
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DS1307_REG_CONTROL_RS0 = $01;
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Rate Select 2 (See datasheet for values)
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[Expand]
DS1337 control register constants DS1337_REG_CONTROL_*
DS1337_REG_CONTROL_nEOSC = $80;
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DS1339_REG_CONTROL_BBSQI = $20;
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DS3231_REG_CONTROL_BBSQW = $40;
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same as BBSQI
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DS1337_REG_CONTROL_RS2 = $10;
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DS1337_REG_CONTROL_RS1 = $08;
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DS1337_REG_CONTROL_INTCN = $04;
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DS1337_REG_CONTROL_A2IE = $02;
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DS1337_REG_CONTROL_A1IE = $01;
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[Expand]
DS1340 control register constants DS1340_REG_CONTROL_*
DS1340_REG_CONTROL_OUT = $80;
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DS1340_REG_CONTROL_FT = $40;
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DS1340_REG_CONTROL_CALIB_SIGN = $20;
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DS1340_REG_CONTROL_M_CALIBRATION = $1f;
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[Expand]
DS1340 flag register constants DS1340_REG_FLAG_*
DS1340_REG_FLAG_OSF = $80;
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DS1337 status register constants DS1337_REG_STATUS_*
DS1337_REG_STATUS_OSF = $80;
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DS1337_REG_STATUS_A2I = $02;
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DS1337_REG_STATUS_A1I = $01;
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[Expand]
RX8025 control1 register constants RX8025_REG_CONTROL1_*
RX8025_REG_CONTROL1_2412 = $20;
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RX8025 control2 register constants RX8025_REG_CONTROL2_*
RX8025_REG_CONTROL2_PON = $10;
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RX8025_REG_CONTROL2_VDET = $40;
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RX8025_REG_CONTROL2_XST = $20;
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Type definitions
DS1307 RTC time
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PDS1307RTCTime = ^TDS1307RTCTime;
TDS1307RTCTime = array[0..6] of Byte;
DS1307 RTC device
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PDS1307RTCDevice = ^TDS1307RTCDevice;
TDS1307RTCDevice = record
| RTC Properties
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RTC:TRTCDevice;
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| DS1307 Properties
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I2C:PI2CDevice;
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The I2C device this RTC is connected to
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Address:Word;
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The I2C address of the device
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Chip:LongWord;
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The chip type (eg DS1307_CHIP_DS1307)
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RTCReg:Byte;
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The register offset for the RTC
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NVRAMReg:Byte;
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The register offset for the NVRAM
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NVRAMSize:Byte;
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The NVRAM size
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ControlReg:Byte;
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The control register offset
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| Statistics Properties
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ReadCount:LongWord;
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Number of direct RTC/NVRAM/Control reads to the device
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WriteCount:LongWord;
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Number of direct RTC/NVRAM/Control writes to the device
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Public variables
None defined
Function declarations
Initialization functions
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procedure DS1307Init;
Description: To be documented
DS1307 RTC functions
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function DS1307RTCStart(RTC:PRTCDevice):LongWord;
Description: To be documented
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function DS1307RTCStop(RTC:PRTCDevice):LongWord;
Description: To be documented
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function DS1307RTCGetTime(RTC:PRTCDevice):Int64;
Description: To be documented
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function DS1307RTCSetTime(RTC:PRTCDevice; const Time:Int64):Int64;
Description: To be documented
DS1307 helper functions
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function DS1307ReadRTC(RTC:PRTCDevice; Buffer:Pointer; Size:LongWord):LongWord;
Description: To be documented
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function DS1307WriteRTC(RTC:PRTCDevice; Buffer:Pointer; Size:LongWord):LongWord;
Description: To be documented
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function DS1307ReadNVRAM(RTC:PRTCDevice; Offset:Byte; Buffer:Pointer; Size:LongWord):LongWord;
Description: To be documented
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function DS1307WriteNVRAM(RTC:PRTCDevice; Offset:Byte; Buffer:Pointer; Size:LongWord):LongWord;
Description: To be documented
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function DS1307ReadControl(RTC:PRTCDevice; var Control:Byte):LongWord;
Description: To be documented
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function DS1307WriteControl(RTC:PRTCDevice; Control:Byte):LongWord;
Description: To be documented
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function DS1307DefaultRTCTime(RTC:PRTCDevice; Buffer:Pointer; Size:LongWord):Boolean;
Description: To be documented
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function DS1307FileTimeToRTCTime(RTC:PRTCDevice; const FileTime:Int64; Buffer:Pointer; Size:LongWord):Boolean;
Description: To be documented
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function DS1307RTCTimeToFileTime(RTC:PRTCDevice; Buffer:Pointer; Size:LongWord; var FileTime:Int64):Boolean;
Description: To be documented
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