MPC574xP Clock Calculator Guide
How to use MPC5744P tool to easily calculate device frequency domains
by: NXP Semiconductors
1 Introduction
NXP’s MPC574xP is a lockstep, dual-core 32-bit microcontroller intended for
safety and chassis applications. This application note will refer to any device
in the MPC574xP family, MPC5741P, MPC5742P, MPC5743P, and MPC5744P,
as simply “MPC5744P.”
The MPC5744P supports an 8-44 MHz external oscillator (XOSC), a 16 MHz
internal RC oscillator (IRCOSC), and two phase locked loops (PLL) for a
maximum operating frequency of 200 MHz. The IRCOSC is selected out of
reset so increasing the operating frequency from 16 MHz requires additional
configuration. The MPC574xP clock calculator is meant to complement the
reference manual. It seeks to simplify the clock configuration process by
providing a graphical, interactive tool to help the user find the correct register
settings in order to achieve the desired clock frequencies.
Accompanying this application note is the clock calculator. You can download
it from MPC574xP_Clock_Calculator.
The clock calculator makes use of macros to perform functions like resetting
the spreadsheet to initial values, configuring all clock frequencies to the
maximum allowable settings, and copying generated code. Macros must be
enabled in the user's MS Excel to access these features. If macros are turned
off however, the tool will still be able to calculate clock frequencies, but the
aforementioned features will be disabled. To turn on macros in MS Excel 2016,
go to the Developer tab on the top toolbar and click on Macro Security. A popup
window will appear. In it, select Enable all macros.
Figure 1. Enabling macros
Contents
1 Introduction..........................................1
2 Clock calculator design...................... 2
2.1 Tree......................................... 3
2.2 Oscillator control..................... 6
2.3 Peripheral domains................. 6
2.4 LFAST clocking....................... 7
2.5 PLLx........................................9
2.6 Reference Tables
(pll0_phi, pll0_phi1, and
pll1_phi)...................................9
2.7 Summary...............................10
2.8 Limits.....................................13
3 Clock tool example use case:
configure ADC to PLL0 at 80 MHz. 14
3.1 Configure ADC_CLK............. 15
3.1.1 Configure the
oscillator.................... 16
3.1.2 Configure PLL0.......18
3.1.3 Finish setting
ADC_CLK..................23
3.2 Configure ADC bus clock
to 40 MHz PLL.......................24
3.3 Observe the registers............25
3.4 Copy the code.......................26
4 Conclusion......................................... 27
5 Revision history.................................27
NXP Semiconductors
Document Number: AN5393
Application Note Rev. 9, April 2018
2 Clock calculator design
The MPC574xP clock calculator takes the form of an interactive Microsoft Excel spreadsheet organized into multiple tabs as shown
in the following figure.
Figure 2. MPC574xP clock calculator setup
Clock sources (e.g. oscillators and PLLs) propagate to the various clock domains from which the MCU modules take their clocks.
Most cells representing clock domain frequencies are not to be modified manually. The user is meant to enter frequencies to the
few select clock sources and all clock domain frequencies derive from these sources. Several clock domain inputs are meant to
be modified manually as they represent external clocks that are driven into a pin. There are also input cells that set muxes and
clock dividers. All cells that take entries have blue borders instead of black, shown below.
Figure 3. Input cells vs. output cells
Clock calculator design
MPC574xP Clock Calculator Guide, Rev. 9, April 2018
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NXP Semiconductors