Kinetis K81 v1.0

This document shows the documentation for the Rhomb.io Kinetis K81 Module.

Overview

The Kinetis K81 Module is a certified Rhomb.io master module that contains a 32 bit ARM MCU. It can be mounted whith Kinetis K80, K81, K82 and KL82 MCUs from NXP, all of them with advanced security capabilities. For more information look at NXP web: K8x and KL8x

The next figure show a 3D view for the Kinetis K81 Module.

Kinetis K81 3D BOTTOM.png Kinetis K81 3D TOP.png


Applications

  • Point-of-sale (POS)
  • Smart Watches
  • Smart Metering
  • Building control
  • Home automation and security
  • loT data concentrators
  • Portable healthcare
  • Smart energy gateways
  • Wearable Healthcare Patch

Module specification

As a Summary, these are the main features of the Kinetis K81 module:

Comparative
K80 K81 K82 KL82
MCU ARM Cortex-M4 ARM Cortex-M0
Max. Operating Frequency 150 MHz 74 MHz
Flash Memory 256 KB 128 KB
SRAM Memory 256 KB 96 KB
Operating voltage 1.7 - 3.6 V
Onboard system oscillator 12 MHz
Onboard RTC oscillator 32.768 KHz
I2C 2
SPI 1
QSPI 1
LPUART 4 2
I2s 1 1 (Emulated)
SDIO 4 data bits not supported
Interrupt pins 3
PWM outputs 4
Analog Inputs 15 14 [1] 15 14 [1]
Digital I/O 76
USB USB 2.0 OTG

As we can see in the table above, Kinetis K81 module has 76 digital input/output pins (most of them used as analog inputs, PWM, I2C, LPUART, I2S, etc.) and a USB 2.0 OTG interface which can be used, for example, to controle some slave modules, to program de MCU, to read/write in a USB memory, to communicate which an host computer (or a RHOMB core), etc.

We have a dedicated RTC supply and oscillator (32.768 KHz) so it will continue working when the main core is in "deep-sleep" mode and can be used to wake it up periodically.

Main clock uses the onboard 12 MHz resonator in combination with the internal PLL/FLL to generate the system clock, several frequencies supported.

The following figure identifies the main Integrated Circuits (IC) onboard.

Kinetis K81 3D TOP Identified.jpg Kinetis-K81-3D BOTTOM Identified.jpg

The next figure shows the Block Diagram for the Kinetis K81 Module.

Kinetis K81 Diagram.png

Connections

GPIO

The following table summarizes the GPIOs used on the Kinetis K81 Module. Note that 4 of them can be configured as interrupt sources.

Rhomb.io pinout Signal (module) Device Interruption Rhomb.io pinout Signal (module) Device Interruption
IO0 IO0 Yes/No IO8 PWM Yes/No
IO1 IO1 Yes/No IO9 PWM Yes/No
IO2 NMI / BOOTCFG0 Yes IO10 PWM Yes/No
IO3 INT Yes IO11 PWM Yes/No
IO4 Watch-dog Yes IO12 TXD4 Yes/No
IO5 Pulse Counter Yes IO13 RXD4 Yes/No
IO6 IO6 Yes/No IO14 TXD3 Yes/No
IO7 IO7 Yes/No IO15 RXD3 Yes/No

For more details, look at the module specifications for the Rhomb.io standard.

Serial interfaces

The following table indicates the available serial interfaces on the Rhomb.io standard and which of them are in use. The table also shows the nomenclature used on the Rhomb.io standard for auxiliary connections and its corresponding on the schematic.

Signal (Rhomb.io) Signal (module) Used by Signal (Rhomb.io) Signal (module) Used by
I2C0 SPI
SDA0 all MCUs SPI_MISO all MCUs
SCL0 all MCUs SPI_MOSI all MCUs
I2C1 SPI_CLK all MCUs
SDA1 all MCUs SPI_SS all MCUs
SCL1 all MCUs
UART0 USB
RXD0 all MCUs USB_DATA_N USB host all MCUs
TXD0 all MCUs USB_DATA_P USB host all MCUs
UART1 USB
RXD1 all MCUs USB_D_P USB slaves all MCUs
TXD1 all MCUs USB_D_N USB slaves all MCUs

The I2C pull-ups resistors (4K7) are mounted onboard. For more details, look at the module specifications for the Rhomb.io standard.

Kinetis K81 module implements an USB switch selector controled by the uC that allows to connect with slaves modules or computer host (default).


OTHER INTERFACEs

The next table shows the nomenclature used on the schematic and its corresponding on the rhom standard for the Secure Digital Input Output (SDIO) and SPI Flash Interface (SPIFI).

NOTE: SDIO interface is only available on K8x versions. In KL82 are just GPIOs.

Signal (Rhomb.io) Signal (module) Used by Signal (Rhomb.io) Signal (module) Used by
SDIO QSPI
SDIO0_CMD IO27/SDIO0_CMD K8x versions SPIFI_CS IO40/SPIFI_ICS all MCUs
SDIO0_CLK IO29/SDIO0_CLK K8x versions SPIFI_CLK IO41/SPIFI_CLK all MCUs
SDIO0_DATA0 IO30/SDIO0_D0 K8x versions SPIFI_IO0 IO42/SPIFI_IO0 all MCUs
SDIO0_DATA1 IO31/SDIO0_D1 K8x versions SPIFI_IO1 IO43/SPIFI_IO1 all MCUs
SDIO0_DATA2 IO25/SDIO0_D2 K8x versions SPIFI_IO2 IO44/SPIFI_IO2 all MCUs
SDIO0_DATA3 IO26/SDIO0_D3 K8x versions SPIFI_IO3 IO45/SPIFI_IO3 all MCUs
SDIO0_CDN NC NC

The next table shows the nomenclature used on the schematic and its corresponding on the rhom standard for the Integrated Interchip Sound (I2S) interface.

NOTE: I2S interface is hardware supported on K8x versions and emulated throught FLEXIO lines on KL82.

Signal (Rhomb.io) Signal (module) Used by
I2S
IO16/I2S_SDI all MCUs
IO17/I2S_SDO all MCUs
IO18/I2S_SCL all MCUs
IO19/I2S_LRCK all MCUs
IO20/I2S_CDCLK all MCUs

For more details, look at the module specifications for the Rhomb.io standard.

Power

As per the supply lines used on the board, there is a summary on the next table.

Signal (Rhomb.io) Signal (module) Voltage (V) Used
1V8 150mA 1V8 1.8 Selectable
2V8 150mA 2V8 2.8 Selectable
VCH 5 No
VSYS 3 - 5.5 No
Buck8 3V3 3.3 Selectable
Buck9 3V3 3.3 Selectable
BAT_RTC VBAT 3.3 RTC power supply

Main Power supply can be selected from 1V8, 2V8 & 3V3 (Buck8 & Buck9 are shorted), in KL82 version USB is powered directly from 3V3

For more details, look at the module specifications for the Rhomb.io standard.

Other signals

On the following table it is shown the remaining signals from the Rhomb.io module connectors standard.

Signal (Rhomb.io) Signal (module) Used by
CLK_32KH CLK_32KH Selectable as RTC CLK input
AD_OUT NC NC
PWM_INT NC NC

For more details, look at the module specifications for the Rhomb.io standard.

Kinetis K81 module has an onboard RTC oscillator, but it can be removed and use the 32KH signal from Rhomb connector

Schematics

Click the image below to download the schematic files.

Bill of materials

The BOM for different versions are here:

K80 Version

K81 Version

K82 Version

KL82 Version

Fabrication files

Click the image below to download the fabrication files.

Mechanical specifications

Board


Dimmensions Kinetis K81.jpg

Warranty

  • Precaution against Electrostatic Discharge. When handling Rhomb.io products, ensure that the environment is protected against static electricity. Follow the next recommendations:
  1. The users should wear anti-static clothing and use earth band when manipulating the device.
  2. All objects that come in direct contact with devices should be made of materials that do not produce static electricity that would cause damage.
  3. Equipment and work table must be earthed.
  4. Ionizer is recommended to remove electron charge.
  • Contamination. Be sure to use semiconductor products in the environment that may not be exposed to dust or dirt adhesion.
  • Temperature/Humidity. Semiconductor devices are sensitive to environment temperature and humidity. High temperature or humidity may deteriorate semiconductor devices characteristics. Therefore avoid storage or usage in such conditions.
  • Mechanical Shock. Care should be exercised not to apply excessive mechanical shock or force on the connectors and semiconductors devices.
  • Chemical. Do not expose semiconductor device to chemical because reaction to chemical may cause deterioration of device characteristics.
  • Light Protection. In case of non-EMC (Epoxy Molding Compound) package, do not expose semiconductor IC to strong light. It may cause devices malfunction. Some special products which utilize the light or have security function are excepted from this specification.
  • Radioactive, Cosmic and X-ray. Semiconductor devices can be influenced by radioactive, cosmic ray or X-ray. Radioactive, cosmic and X-ray may cause soft error during device operation. Therefore semiconductor devices must be shielded under environment that may be exposed to radioactive, cosmic ray or X-ray.
  • EMS (Electromagnetic Susceptibility). Note that semiconductor devices characteristics may be affected by strong electromagnetic waves or magnetic field during operation.

Disclaimer

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  1. 1.0 1.1 AD10 is used as a tamper detection pin in K81 version and is not connected on KL82.