Unit PL031
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Description
ARM PrimeCell PL031 Real Time Clock Driver unit
The PL031 is a simple memory mapped Real Time Clock (RTC) device that supports a single 32-bit time counter based on the Unix time format which starts at 1 Jan 1970 and runs out at 19 Jan 2038.
The device also includes a single alarm value which can trigger an interrupt when the selected time is reached.
This driver currently does not support reading or setting the alarm value.
Constants
PL031 specific constants
PL031_* PL031_RTC_DESCRIPTION = 'ARM PrimeCell PL031 Real Time Clock';
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Description of PL031 device |
PL031_MIN_TIME = TIME_TICKS_TO_1970;
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Time starts at 01/01/1970 00:00:00 (MM/DD/YY HH:MM:SS) |
PL031_MAX_TIME = 137919572470000000;
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Time ends at 19/1/2038 03:14:07 (MM/DD/YY HH:MM:SS) |
PL031 RTC control register
PL031_RTC_CR_* PL031_RTC_CR_EN = (1 shl 0);
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If set to 1, the RTC is enabled. Once it is enabled, any writes to this bit have no effect on the RTC until a system reset. A read returns the status of the RTC. |
PL031 RTC interrupt mask set and clear register
PL031_RTC_IMSC_* PL031_RTC_IMSC_INTR_SET = (1 shl 0);
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PL031_RTC_IMSC_INTR_CLEAR = (0 shl 0);
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PL031 RTC raw interrupt status register
PL031_RTC_RIS_* PL031_RTC_RIS_INTR = (1 shl 0);
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PL031 RTC masked interrupt status register
PL031_RTC_MIS_* PL031_RTC_MIS_INTR = (1 shl 0);
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PL031 RTC interrupt clear register
PL031_RTC_ICR_* PL031_RTC_ICR_INTR = (1 shl 0);
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Type definitions
PL031 real time clock (RTC) registers
PPL031RTCRegisters = ^TPL031RTCRegisters;
TPL031RTCRegisters = record
| Note: Layout of the PL031 registers (See: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0224b/i1005653.html) | |
DR:LongWord;
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Data register |
MR:LongWord;
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Match register |
LR:LongWord;
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Load register |
CR:LongWord;
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Control register |
IMSC:LongWord;
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Interrupt mask set and clear register |
RIS:LongWord;
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Raw interrupt status register |
MIS:LongWord;
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Masked interrupt status register |
ICR:LongWord;
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Interrupt clear register |
PL031 real time clock (RTC)
PPL031RTC = ^TPL031RTC;
TPL031RTC = record
| RTC Properties | |
RTC:TRTCDevice;
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| PL031 Properties | |
IRQ:LongWord;
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Registers:PPL031RTCRegisters;
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Device registers |
| Statistics Properties | |
InterruptCount:LongWord;
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Number of interrupt requests received by the device |
Public variables
None defined
Function declarations
PL031 functions
function PL031RTCCreate(Address:LongWord; const Name:String; IRQ:LongWord):PRTCDevice;
Description: Create, register and start a new PL031 RTC device which can be accessed using the RTC API
| Address | The address of the PL031 registers |
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| Name | The text description of this device which will show in the device list (Optional) |
| IRQ | The interrupt number for the PL031 |
| Return | Pointer to the new RTC device or nil if the RTC device could not be created |
function PL031RTCDestroy(RTC:PRTCDevice):LongWord;
Description: Stop, deregister and destroy a PL031 RTC device created by this driver
| RTC | The RTC device to destroy |
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| Return | ERROR_SUCCESS if completed or another error code on failure |
PL031 RTC functions
function PL031RTCStart(RTC:PRTCDevice):LongWord;
Description: Implementation of RTCDeviceStart API for PL031 RTC
| Note | Not intended to be called directly by applications, use RTCDeviceStart instead |
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function PL031RTCStop(RTC:PRTCDevice):LongWord;
Description: Implementation of RTCDeviceStop API for PL031 RTC
| Note | Not intended to be called directly by applications, use RTCDeviceStop instead |
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function PL031RTCGetTime(RTC:PRTCDevice):Int64;
Description: Implementation of RTCDeviceGetTime API for PL031 RTC
| Note | Not intended to be called directly by applications, use RTCDeviceGetTime instead |
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function PL031RTCSetTime(RTC:PRTCDevice; const Time:Int64):Int64;
Description: Implementation of RTCDeviceSetTime API for PL031 RTC
| Note | Not intended to be called directly by applications, use RTCDeviceSetTime instead |
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PL031 helper functions
function PL031FileTimeToRTCTime(RTC:PRTCDevice; const FileTime:Int64; var RTCTime:LongWord):Boolean;
Description: Convert a FileTime value in 100 nanosecond ticks since 1 January 1601 to the time format of the PL031 RTC which is seconds since 1 January 1970
| Note | None documented |
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function PL031RTCTimeToFileTime(RTC:PRTCDevice; RTCTime:LongWord; var FileTime:Int64):Boolean;
Description: Convert a PL031 RTC time value in seconds since 1 January 1970 to the FileTime format which is 100 nanosecond ticks since 1 January 1601
| Note | None documented |
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