NXP Semiconductors KE17Z Series User manual

KE17Z Hardware Developer's Guide
NXP Semiconductors Document identifier: KE17ZHDG
User Guide Rev. 0.1, 13 December 2021

Contents
Chapter 1 Overview............................................................................................... 3
Chapter 2 Power Supply........................................................................................ 6
Chapter 3 Clock Module........................................................................................ 8
Chapter 4 Reset Circuit........................................................................................10
Chapter 5 Debug and Programming Interface..................................................... 11
Chapter 6 Touch Sensing Input........................................................................... 12
Chapter 7 ADC Input Circuit................................................................................ 14
Chapter 8 Digital GPIO and Unused Pin..............................................................16
Chapter 9 General Board Layout Guidelines....................................................... 17
Appendix A Revision History................................................................................18
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Chapter 1
Overview
This document provides board-level hardware design guidelines for the KE17Z family products (see table). The hardware design
guidelines are similar for this product family. In this document, the MKE17Z256VLL7 device is used for demonstration purposes.
Table 1. KE17Z family
Product Memory Package IO and ADC channel HMI
Part number Flash (KB) SRAM
(KB)
Pin count Package GPIOs GPIOs
(INT/HD) 1
ADC channels TSI
MKE17Z256VLL7 256 48 100 LQFP 89 89/8 16 50ch
MKE17Z256VLH7 256 48 64 LQFP 58 58/8 16 47ch
MKE17Z128VLL7 128 32 100 LQFP 89 89/8 16 50ch
MKE17Z128VLH7 128 32 64 LQFP 58 58/8 16 47ch
MKE13Z256VLL7 256 48 100 LQFP 89 89/8 16 25ch
MKE13Z256VLH7 256 48 64 LQFP 58 58/8 16 22ch
MKE13Z128VLL7 128 32 100 LQFP 89 89/8 16 25ch
MKE13Z128VLH7 128 32 64 LQFP 58 58/8 16 22ch
MKE12Z256VLL7 256 48 100 LQFP 89 89/8 16 -
MKE12Z256VLH7 256 48 64 LQFP 58 58/8 16 -
MKE12Z128VLL7 128 32 100 LQFP 89 89/8 16 -
MKE12Z128VLH7 128 32 64 LQFP 58 58/8 16 -
1. INT: interrupt pin numbers; HD: high drive pin numbers
KE17Z MCUs extend Kinetis E family to dual TSI performance and broader scalability. Robust and dual TSI provides high-level
stability and accuracy to customer's HMI system. 1 Msps ADC and FlexTimer help build a perfect solution for a simple BLDC motor
control system.
Following are the general features of the KE17Z series MCUs:
• Arm® Cortex®-M0+ core, supports up to 72 MHz frequency, with 2.35 CoreMark/MHz.
• Scalable memory up to 256 KB program flash and up to 48 KB SRAM
• 5 V power supply ranges from 2.7 V to 5.5 V.
• Dual capacitive touch sensing modules offer 2 x 25 ch touch sensing channels supporting both self-cap and mutual cap
technologies.
• Precision mixed-signal capability with 1x high-speed on-chip analog comparator and 1× 12-bit analog-to-digital converter
(ADC) with up to 16 channel analog inputs per module, up to 1 Msps.
• Flexible timers including 3 × Flex Timers (FTM) for PWM generation, offering up to 8 standard PWM channels
This document describes the following module and provides appropriate hardware design related recommendations:
•Power Supply
•Clock Module
•Reset Circuit
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•Debugging and Programming Interface
•Touch Sensing interface (TSI)
•ADC Input Circuit
•Digital GPIO and unused pin
•General Board Layout Guidelines
A general schematic example is shown in the following figure.
Figure 1. X-KE17Z-TSI-EVB schematic example
1.1 Related documentation
The table below lists and explains the additional documents and resources that you can refer to for more information on KE17Z
MCUs. Some of the documents listed below may be available only under a non-disclosure agreement (NDA). To request access
to these documents, contact your local field applications engineer (FAE) or sales representative.
Table 2. Related documentation
Document Description Link/how to access
Kinetis KE17Z/13Z/12Z with
up to 256 KB Flash
Reference Manual
Intended for system software and hardware
developers and applications programmers who
want to develop products with this device
KE1xZP100M72SF1RM
Table continues on the next page...
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Table 2. Related documentation (continued)
Document Description Link/how to access
Kinetis KE17Z/13Z/12Z with
up to 256 KB Flash Data Sheet
Provides information about electrical
characteristics, hardware design considerations,
and ordering information
KE1xZP100M72SF1
AN5426 Hardware
Design Guidelines for
S32K1xx Microcontrollers
Explains Hardware Design Guidelines for
S32K1xx Microcontrollers
AN5426
KE15ZTSIUG KE15Z Touch
Sensing Interface User
Guide
Explains the new TSI (Touch Sensing Interface)
measurement and how to develop the software and
hardware board from the application point of view
KE15ZTSIUG
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Chapter 2
Power Supply
The power supply of KE17Z ranges from 2.7 V to 5.5 V, the detailed operating requirements are listed below. Note that the
difference between VDD (digital power supply) and VDDA (analog power supply) cannot exceed 0.1 V, so it is recommended to
connect VDD and VDDA directly in practice. Also, the power supply ramp up rate should be limited within 100 V/ms.
Table 3. Power supply
Symbol Description Min. Max. Unit Notes
VDD Supply voltage 2.7 5.5 V
VDDA Analog supply voltage 2.7 5.5 V
VDD –
VDDA
VDD-to-VDDA differential voltage – 0.1 0.1 V
VSS –
VSSA
VSS-to-VSSA differential voltage – 0.1 0.1 V
The decoupling capacitors (100 nF as shown in the figure below) are required to filter out the system noise. Figure below shows
examples of decoupling capacitors on the schematic, at least one decoupling capacitor per power pin is recommended. On PCB
layout level, all decoupling capacitors should be placed as close as possible to each of their respective power supply pin; the
ground side of the decoupling capacitor should have a via to the pad which goes directly down to the ground plane. The decoupling
capacitors should not route to the power plane through a long trace. The types and values of the decoupling capacitor depend on
the noise level and frequency. The typical value is usually in the range of 0.01 μF to 0.1 μF.
The bulk capacitor (10 μF as shown in the figure below) acts as a local power supply to the power pin, its typical value is 10 μF.
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Chapter 3
Clock Module
The KE17Z has the following clock sources:
• Fast internal reference clock (FIRC): 48 MHz high-accuracy (up to ±1%) fast internal reference clock (FIRC) for normal
Run as the default system clock source after reset.
• Slow internal reference clock (SIRC): 8 MHz/2 MHz.
• LPFLL: Supports only up to 72 MHz
• LPO128K: 128 KHz always on internal low-power oscillator clock, for WDOG, LPTMR, EWM, PORT Control.
• External square wave input: Up to 60 MHz DC external square wave input clock
• External oscillator clock (OSC): high range 4 - 40 MHz (with low power or high gain mode) and low range 32 - 40 kHz
(with high-gain mode only)
3.1 External oscillator circuit design
The EXTAL and XTAL pins provide the interface for a Crystal oscillator. EXTAL is the input to the crystal oscillator amplifier. XTAL
is the output of the crystal oscillator amplifier. The pierce oscillator provides a robust, low-noise, and low-power external clock
source. It is designed for optimal start-up margin with typical crystal oscillators. KE17Z supports two ranges of external oscillator:
• high-range: 4 - 40 MHz (with low-power or high-gain mode)
Table 4. External crystal/resonator connections
Oscillator mode Oscillator mode
Low frequency (32.768 kHz), high gain Diagram 3
High frequency (1-32 MHz), low power Diagram 2
High frequency (1-32 MHz), high gain Diagram 3
• low-range: 32 - 40 kHz (with high-gain mode only)
The typical circuit design of the external oscillator is shown in the figure below. For the low-power use case, the low-power
oscillator mode is recommended, as shown in Diagram 2, thus the 1 Mohm RF (feedback resistor) is not needed in this case. For
noise use case, the high-gain oscillator is preferred as shown in Diagram 3. The user needs to add 1 Mohm RF (feedback resistor),
also the use needs to double check with the crystal vendor about the exact value of RS (series resistor). The load capacitors of C1
and C2 must be provided by external capacitors and their load capacitance depends on the crystal or resonator manufacturers'
recommendation. Check the crystal datasheet for the recommended values. And, also consider the parasitic capacitance of
package and board.
Figure 2. Crystal circuit design – Diagram 2
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Figure 3. Crystal circuit design – Diagram 3
3.2 EMC considerations
As the clock circuit is very sensitive to the noise, you need to pay attention to the following guidelines on PCB layout:
Avoid placing any signal traces close to the clock circuit.
Place the external crystal to the EXTAL/XTAL pins as close as possible.
A ground area should be placed under the crystal oscillator area. This ground guard ring must be clean ground. This means that
no current from and to other devices should be flowing through the guard ring. This guard ring should be connected to VSS with a
short trace. Never connect the ground guard ring to any other ground signal on the board. Also avoid implementing ground loops.
The following figure shows the recommended placement and routing for the oscillator layout.
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Chapter 4
Reset Circuit
Resetting the MCU provides a way to start processing from a known set of initial conditions. System reset begins with the on-chip
regulator in full regulation and system clocking generation from an internal reference.
For all reset sources, the RESET_B pin is driven low by the MCU for at least 128 bus clock cycles and until the flash memory
initialization is completed. After flash memory initialization completes, the RESET_B pin is released and the internal chip reset
is deasserted. Keeping the RESET_B pin asserted externally delays the negation of the internal chip reset. The detailed boot
sequence is shown in the figure above.
As shown in the schematic example figure, the reset circuit consists of an external pullup resistor added between reset pin to power
supply, a capacitor between the reset pin to ground, and an optional reset button.
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