LPC1767FBD100,551 NXP Semiconductors, LPC1767FBD100,551 Datasheet - Page 567

• Manufacturer Part Number: LPC1767FBD100,551
• Description: IC ARM CORTEX MCU 512K 100-LQFP
• Manufacturer: NXP Semiconductors
• Series: LPC17xxr

Specifications of LPC1767FBD100,551

• Core Processor: ARM® Cortex-M3™
• Core Size: 32-Bit
• Speed: 100MHz
• Connectivity: Ethernet, I²C, IrDA, Microwire, SPI, SSI, UART/USART
• Peripherals: Brown-out Detect/Reset, DMA, I²S, Motor Control PWM, POR, PWM, WDT
• Number Of I /o: 70
• Program Memory Size: 512KB (512K x 8)
• Program Memory Type: FLASH
• Ram Size: 64K x 8
• Voltage - Supply (vcc/vdd): 2.4 V ~ 3.6 V
• Data Converters: A/D 8x12b, D/A 1x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 100-LQFP
• Processor Series: LPC17
• Core: ARM Cortex M3
• 3rd Party Development Tools: MDK-ARM, RL-ARM, ULINK2, MCB1760, MCB1760U, MCB1760UME
• For Use With: 622-1005 - USB IN-CIRCUIT PROG ARM7 LPC2K
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details
• Other names: 568-4967; 935289808551

NXP Semiconductors
Table 519. Calibration register (CALIBRATION - address 0x4002 4040) bit description
UM10360
User manual
Bit
16:0
17
31:12
Symbol
CALVAL
CALDIR
27.6.5 Calibration procedure
Value
-
1
0
The calibration logic can periodically adjust the time counter either by not incrementing
the counter, or by incrementing the counter by 2 instead of 1. This allows calibrating the
RTC oscillator under some typical voltage and temperature conditions without the need to
externally trim the RTC oscillator.
A recommended method for determining the calibration value is to use the CLKOUT
feature to unintrusively observe the RTC oscillator frequency under the conditions it is to
be trimmed for, and calculating the number of clocks that will be seen before the time is off
by one second. That value is used to determine CALVAL.
If the RTC oscillator is trimmed externally, the same method of unintrusively observing the
RTC oscillator frequency may be helpful in that process.
Backward calibration
Enable the RTC timer and calibration in the CCR register (set bits CLKEN = 1 and
CCALEN = 0). In the CALIBRATION register, set the calibration value CALVAL ≥ 1 and
select CALDIR = 1.
Forward calibration
Enable the RTC timer and calibration in the CCR register (set bits CLKEN = 1 and
CCALEN = 0). In the CALIBRATION register, set the calibration value CALVAL ≥ 1 and
select CALDIR = 0.
•
•
•
•
•
•
Description
If enabled, the calibration counter counts up to this value. The maximum value is 131,
072 corresponding to about 36.4 hours. Calibration is disabled if CALVAL = 0.
Calibration direction
Backward calibration. When CALVAL is equal to the calibration counter, the RTC
timers will stop incrementing for 1 second.
Forward calibration. When CALVAL is equal to the calibration counter, the RTC timers
will jump by 2 seconds.
Reserved, user software should not write ones to reserved bits. The value read from a
reserved bit is not defined.
The SEC timer and the calibration counter count up for every 1 Hz clock cycle.
When the calibration counter reaches CALVAL, a calibration match occurs and all
RTC timers will be stopped for one clock cycle so that the timers will not increment in
the next cycle.
If an alarm match event occurs in the same cycle as the calibration match, the alarm
interrupt will be delayed by one cycle to avoid a double alarm interrupt.
The SEC timer and the calibration counter count up for every 1 Hz clock cycle.
When the calibration counter reaches CALVAL, a calibration match occurs and the
RTC timers are incremented by 2.
When the calibration event occurs, the LSB of the ALSEC register is forced to be one
so that the alarm interrupt will not be missed when skipping a second.
All information provided in this document is subject to legal disclaimers.
Chapter 27: LPC17xx Real-Time Clock (RTC) and backup registers
Rev. 2 — 19 August 2010
UM10360
© NXP B.V. 2010. All rights reserved.
567 of 840
Reset
value
NC
NC
NA