LPC1343FHN33,551 NXP Semiconductors, LPC1343FHN33,551 Datasheet - Page 276

• Manufacturer Part Number: LPC1343FHN33,551
• Description: IC MCU 32BIT 32KB FLASH 33HVQFN
• Manufacturer: NXP Semiconductors
• Series: LPC13xxr

Specifications of LPC1343FHN33,551

• Program Memory Type: FLASH
• Program Memory Size: 32KB (32K x 8)
• Package / Case: 33-VQFN Exposed Pad, 33-HVQFN, 33-SQFN, 33-DHVQFN
• Core Processor: ARM® Cortex-M3™
• Core Size: 32-Bit
• Speed: 72MHz
• Connectivity: I²C, Microwire, SPI, SSI, SSP, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, WDT
• Number Of I /o: 28
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 3.6 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: LPC13
• Core: ARM Cortex M3
• Data Bus Width: 32 bit
• Data Ram Size: 8 KB
• Interface Type: I2C, UART
• Maximum Clock Frequency: 72 MHz
• Number Of Programmable I/os: 28
• Number Of Timers: 4
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: MDK-ARM, RL-ARM, ULINK2, KSK-LPC1343
• Development Tools By Supplier: OM11039, OM11040, OM11046, OM11048
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 8 Channel
• Package: 33HVQFN EP
• Device Core: ARM Cortex M3
• Family Name: LPC1000
• Maximum Speed: 72 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 622-1005 - USB IN-CIRCUIT PROG ARM7 LPC2K
• Eeprom Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 568-4944; 935289655551

NXP Semiconductors
16.7 Example timer calculations
UM10375
User manual
The following examples illustrate selecting SysTick timer reload values for different
system configurations. All of the examples calculate an interrupt interval of
10 milliseconds, as the SysTick timer is intended to be used, and there are no rounding
errors.
System clock = 72 MHz
Program the CTRL register with the value 0x7 which selects the system clock as the clock
source and enables the SysTick timer and the SysTick timer interrupt.
RELOAD = (system clock frequency × 10 ms) −1 = (72 MHz × 10 ms) −1 = 720000 −1 =
719999 = 0x000AFC7F
System tick timer clock = 24 MHz
Program the CTRL register with the value 0x3 which selects the clock from the system tick
clock divider (use DIV = 3) as the clock source and enables the SysTick timer and the
SysTick timer interrupt.
RELOAD = (system tick timer clock frequency × 10 ms) −1 = (24 MHz × 10 ms) −1 =
240000 −1 = 239999 = 0x0003A97F
System clock = 12 MHz
Program the CTRL register with the value 0x7 which selects the system clock as the clock
source and enables the SysTick timer and the SysTick timer interrupt.
In this case the system clock is derived from the IRC clock.
RELOAD = (system clock frequency × 10 ms) −1 = (12 MHz × 10 ms) −1 = 120000 −1 =
119999 = 0x0001 D4BF
To use the system tick timer, do the following:
1. Program the LOAD register with the reload value RELOAD to obtain the desired time
2. Clear the VAL register by writing to it. This ensures that the timer will count from the
interval.
LOAD value rather than an arbitrary value when the timer is enabled.
All information provided in this document is subject to legal disclaimers.
Rev. 2 — 7 July 2010
Chapter 16: LPC13xx System tick timer
UM10375
© NXP B.V. 2010. All rights reserved.
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