LPC1759FBD80,551 NXP Semiconductors, LPC1759FBD80,551 Datasheet - Page 508

• Manufacturer Part Number: LPC1759FBD80,551
• Description: IC ARM CORTEX MCU 512K 80-LQFP
• Manufacturer: NXP Semiconductors
• Series: LPC17xxr

Specifications of LPC1759FBD80,551

• Program Memory Type: FLASH
• Program Memory Size: 512KB (512K x 8)
• Package / Case: 80-LQFP
• Core Processor: ARM® Cortex-M3™
• Core Size: 32-Bit
• Speed: 120MHz
• Connectivity: CAN, I²C, IrDA, Microwire, SPI, SSI, SSP, UART/USART, USB OTG
• Peripherals: Brown-out Detect/Reset, DMA, I²S, Motor Control PWM, POR, PWM, WDT
• Number Of I /o: 52
• Ram Size: 64K x 8
• Voltage - Supply (vcc/vdd): 2.4 V ~ 3.6 V
• Data Converters: A/D 6x12b, D/A 1x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: LPC17
• Core: ARM Cortex M3
• Data Bus Width: 32 bit
• Data Ram Size: 64 KB
• Interface Type: Ethernet, USB, OTG, CAN
• Maximum Clock Frequency: 120 MHz
• Number Of Programmable I/os: 52
• 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
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12 bit, 6 Channel
• On-chip Dac: 10 bit
• Package: 80LQFP
• Device Core: ARM Cortex M3
• Family Name: LPC17xx
• Maximum Speed: 120 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: 568-4968; 935290523551

NXP Semiconductors
23.6 Example timer calculations
UM10360
User manual
The following examples illustrate selecting System Tick Timer values for different system
configurations. All of the examples calculate an interrupt interval of 10 milliseconds, as the
System Tick Timer is intended to be used.
Example 1)
This example is for the System Tick Timer running from the CPU clock (cclk), which is
100 MHz.
STCTRL = 7. This enables the timer and its interrupt, and selects cclk as the clock source.
RELOAD = (cclk / 100) - 1 = 1,000,000 - 1 = 999,999 = 0xF423F
In this case, there is no rounding error, so the result is as accurate as cclk.
Example 2)
This example is for the System Tick Timer running from the CPU clock (cclk), which is
80 MHz.
STCTRL = 7. This enables the timer and its interrupt, and selects cclk as the clock source.
RELOAD = (cclk / 100) - 1 = 800,000 - 1 = 799,999 = 0xC34FF
In this case, there is no rounding error, so the result is as accurate as cclk.
Example 3)
This example is for the CPU clock (cclk) is taken from the Internal RC Oscillator (IRC),
factory trimmed to 4 MHz.
STCTRL = 7. This enables the timer and its interrupt, and selects cclk as the clock source.
RELOAD = (F
In this case, there is no rounding error, so the result is as accurate as the IRC.
Example 4)
This example is for the System Tick Timer running from an external clock source (the
STCLK pin), which in this case happens to be 32.768 kHz.
STCTRL = 3. This enables the timer and its interrupt, and selects the STCLK pin as the
clock source. STCLK must be selected as the function of the relevant pin. See
Section
RELOAD = (cclk / 100) - 1 = 327.6 - 1 = 327 (rounded up) = 0x0147
In this case, there is rounding error, so the interrupt rate will drift slightly relative to the
input frequency.
8.5.6.
IRC
All information provided in this document is subject to legal disclaimers.
/ 100) - 1 = 40,000 - 1 = 39,999 = 0x9C3F
Rev. 2 — 19 August 2010
Chapter 23: LPC17xx System Tick Timer
UM10360
© NXP B.V. 2010. All rights reserved.
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