HOLT HI-35850 User manual

AN-35850 Rev. New Holt Integrated Circuits
HI-35850 ARINC 429 Protocol IC
1x RECEIVER
1x TRANSMITTER
ADK-35850 Application Development Kit
Users Guide
January 25, 2021

AN-35850
2 Holt Integrated Circuits
REVISION HISTORY
Revision
Date
Description of Change
AN-35850,Rev. New
01-25-2021
Initial Release

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3 Holt Integrated Circuits
Introduction
The Holt ADK-35850 Evaluation board demonstrates the features of Holt’s ARINC 429 HI-35850. The HI-
35850 includes one complete ARINC 429 receiver and transmitter with line driver. The HI-35850 is a new
version of the HI-3585 but has a much higher 12MHz SPI frequency. The example board set includes an
ARM Cortex M3 base board and the HI-35850 plug-in daughter card. The kit uses IAR as the development
IDE and an integrated USB debugger port is included on the base board so no other USB programming
adapters are needed.
This guide describes how to set up and run the pre-programmed demos. Additional support material and
all required project software are found in the included Holt USB memory stick. A version of the
demonstration software is pre-programmed into the microcontroller flash which makes the board
operational right out of the box without installing or running the provided software development tools. A
later section in this guide provides instructions how to install IAR and load the demo program. Installing
IAR is not required to run the demos since this program is pre-programmed in the MCU flash memory.
ADK-35850 Demo Board, mounted on the ARM Cortex M3 MCU Board

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Evaluation Kit Contents
This User Guide.
Holt HI-35850 IAR Software Project and Documentation on an USB memory stick.
IAR Systems Embedded Workbench® for ARM (32KB free KickStart) download link on USB
memory stick.
Plug-in 5V DC power adapter.
USB mini debug interface cable.
RS-232 serial cable, DB-9M to DB-9F for console I/O using a connected computer.
USB to serial dongle adapter.
2-board assembly comprised of:
Upper HI-35850 daughter board and Lower MCU board with (Microchip/Atmel) ARM Cortex M3
16-/32-bit microprocessor, debug interface and regulated 3.3VDC power supply
The HI-35850 daughter card is separable and useable for user prototyping on other platforms.
Hardware Block Diagram
Cortex M3
MCU board HOLT
HI-35850
SPI (4) 12MHz Max.
RS-232 Console
USB Debug Port
LEDs
Debugger SWD or
JTAG, Power
User Push Button
Switches SW1, SW2
SW1 DIPs
(4)
J3, J10 Host I/F Header for
standalone use
RESET Button
SW3
ARINC 429 Receiver
nMR
1 MHz
OSC
5V to 3.3V
Reg +3.3V
5V
ARINC AOUT27 BOUT27
J7, J8
Header
Pins
Status LEDs:
TX amber
ERR red
RX green
User1 green
User2 green
J6
Header
Pins
INT
ARINC AOUT37 BOUT37 J5 Header
Pins
Main host ARM processor card Holt HI-35850 daughter card
3.3V to +5V and
-5V DC-DC
converter

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Push-buttons
Push-button Switches
(on main CM3 board)
DESCRIPTION
SW1
Performs SPI sequences for SPI trouble shooting. See Section
on SPI trouble shooting towards the end of this document.
SW2
Transmits maximum number of FIFO messages (32)
continuously. Press ‘q’ to quit.
DIPSW1 SWITCHES
SWITCH
DEFAULT
DESCRIPTION
SW 1
ON
ON = SPI 12MHz Frequency for HI-35850.
OFF = HI-3585 compatibility mode. Sets SPI frequency
to 2.4MHz.
SW 2
Available to user.
SW 3
Available to user
SW 4
Available to user.

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6 Holt Integrated Circuits
HI-35850 supply current measurements
Jumper shunts J2, J1 and J3 can be removed to isolate 3.3V, +5 and -5V on the HI-35850 to allow current
measurements of the HI-35850.
External Host interface to the HI-35850 daughter board
The HI-35850 daughter board can be separated from the MCU board and connected to a user FPGA or a
host MCU for quick prototyping purposes. The interface signals are provided on J10 header connector and
a few others on J3. The daughter card accepts only 3.3 volts supplied by the lower main board. A DC-DC
LT3463A converter regulator takes 3.3V and generates +/- 5V for the HI-35850. This is meant for
demonstration purposes. See Analog Devices website for performance data and suitability for the
intended application. In summary it operates between -40C to 85C with a conditional note 2. See the data
sheet for more details. https://www.analog.com/en/products/lt3463.html
J10 Pin
SIGNAL
1
nCS(SPI)
2
SCK (SPI)
3
MOSI (SPI)
4
MISO (SPI)
5
RFLAG
6
TFLAG
7
-
8
GND
9
3V3
J3 Pin
SIGNAL
28
nMR
30
RFLAG
32
TFLAG
LED Indicators
LEDS
FUNCTION
TYPICAL USAGE
LED1
User1
Available to user
LED2
User2
Available to user
LED3
RX
Host controlled –Typically flashes On during RX FIFO
message reads in Demo 0.
LED4
ERROR
Host controlled - Available to user to indicate errors
LED5
TX
Host controlled –Typically flashes On when transmitting in
Demo 0.

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Getting Started
The first section of this user guide provides instructions how to set up the demo board and run the built-
in demo programs and utilities that are pre-programmed into the Microchip/Atmel ARM Cortex M3 MCU.
The next section instructs how to install the IAR EWARM IDE and the Holt demonstration program. The
supplied demo program on the USB memory stick is the same demo already programmed in MCU flash
memory.
Hardware Design Overview
Refer to the end of this guide for separate schematic diagrams and bills of material for the upper daughter
board and lower MCU board.
The detachable daughter board can be separated from the lower MCU board for connection to a user-
supplied alternate MCU or FPGA board. The inter-board headers are located on 0.1” (2.54 mm) grid for
compatibility with generic prototyping boards. All host interface signals go through the inter-board
headers. See the External Host interface header pin description for the pin list in the previous section.
The lower ARM Cortex M3 board is based on the flash-programmable Microchip /Atmel AT91SAM3U-EK
MCU. A 4-signal Serial Peripheral Interface (SPI) connects to the HI-35850 DUT. A UART-based serial port
provides RS-232 console I/O (optional). An uncommitted USB 2.0 port is available for future expansion.
Two pushbuttons are available for software interaction. A RESET pushbutton resets the ARM
microprocessor, which in turn controls the DUT Master Reset signal.
The ARM Cortex M3 board includes “J-Link On Board” debug interface, licensed from www.segger.com,
providing out-of-box readiness without having to buy a costly JTAG debug cable. The kit includes a mini
USB cable for connecting the board’s debug interface to your computer. (For users already owning an
ARM debug interface with ribbon-cable connector, an ARM-standard 2x10 debug connector provides
debug connectivity. In this case, jumper JP2 on the bottom of the lower board should be soldered closed
to disable “J-Link On Board”).

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Initial Set Up and Quick Start
Before attempting to run the demo programs, a suitable PC is required with serial COM support so the
demo programs and utilities can be invoked by entering commands on the console menu. This demo
program is already flashed into the Cortex M3 MCU and operates out of the box –no IDE flash
programming is required to run the demo programs.
1. A PC needs a serial (COM) port or USB connection and a “terminal emulation” program like
TeraTerm. Most computers no longer have RS232 com ports so will require a serial-to-USB
adapter, supplied with the ADK. Connect this to the computer’s USB port and the 9 pin connector
to the ADK board.
2. If using Windows 2000 or Windows XP, you can use HyperTerminal for terminal emulation. Open
HyperTerminal by clicking Start then All Programs; click the Windows Accessories then
Communications program group. Double-click HyperTerminal to run it. Skip the next paragraph.
If using Vista, Windows 7 or Windows 10…
HyperTerminal is not included with these versions of Windows. Install the free open-source
terminal emulation program, TeraTerm 4.71, by running the provided teraterm-4.71.exe installer
program from the Holt CD. Accept the license agreement stating redistribution is permitted
provided that copyright notice is retained. The notice can be displayed from the TeraTerm window
by clicking Help then clicking About TeraTerm. Continuing to install…
Accept the default install destination and click Next.
At the Select Components screen, unselect all options except Additional Plug-in =
TTXResizeMenu and click Next.
Select the installed language, then click Next.
Accept the default Start Menu folder, then click Next.
Select any desired shortcuts, then click Next.
At the Ready to Install screen, click Install.
Run the TeraTerm program. At the New Connection screen, select (x)Serial and choose the
selected COM port. Click Setup then Serial Port to open the serial port setup window. Choose
these settings: Baud Rate: 115200, Data: 8 bits, Parity: none, Stop: 1 bit, Flow Control: none.
3. Plug-in the provided 5V DC power supply and connect the cable to the power input jack on the
lower circuit board. If TeraTerm is running and configured correctly, the command menu below
should appear in the console window. This menu appears whenever board power is applied, or
when the RESET pushbutton is pressed. After verifying correct TeraTerm communication with the
evaluation board, the terminal set up can be saved by clicking Setup then Save Setup.

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4. At power up, all the LED’s will briefly flash.
Getting Started with the Demos
After powering up the board the menu of commands are displayed on the console.
-------------------------------------------------
Holt Integrated Circuits HI-35850 CM3 Demo Program Ver. 1.0
Compiled: Jan 11 2021 13:10:28
-------------------------------------------------
DIP switches: 00
Status Reg: 0x0009
Control Reg: 0x2020
Divisor Reg: 0x01
Status Register expected value OK
*************************************************
Holt Integrated Circuits HI-35850, 3585 CM3 Demo Program Ver. 1.0
Compiled: Jan 11 2021 14:14:35
*************************************************
------------- HI-35850 Demo --------------
Press '0' - TX AND RX RECEIVE
Press '1' - Load Transmit FIFO with 32 messages
Press '2' - Load Transmit FIFO with 8 messages
Press '3' - Reads ARINC RX FIFO and displays
Press '4' - Reads ARINC RX FIFO and displays in Loop mode
Press 'M' - Write Label Memory
Press 'm' - Read and Display Label Memory
Press 'l' - Toggle Enable or Disable Label Memory CR2n
----------- UTILITIES -------------
Press 'Space Bar' - Display Selected Registers
Press 'c' - ACLK divisor
Press 'f' - Toggle RFLAG CR15, TFLAG CR14 in Control Word
Press 'h' - Display this Menu again
Press 't' - Toggle Self-Test Mode vs. Normal Mode
Press 's' - Toggle ARINC TX and RX speed
Press 'S' - SPI freq
===========================================================
Press 'H' for this help menu, or press any valid menu key. >>
It is highly recommended to first review the HI-35850 data sheet to gain a basic understanding of the
device so you get the most benefit from the demos and utilities described in this guide.

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Nearly all menu commands entered on the console instruct the ARM MCU to issue SPI Op Codes to write
or read data in the HI-35850. The host configures the HI-35850 by writing to a Control Register using the
SPI interface.
Demo Quick Start Instructions
At anytime Press the space bar at the menu prompt to read and display the Control Register, Status
Register and Divisor Register.
Status Reg: 0x0009
Control Reg: 0x2000
Divisor Reg: 0x01
Demo 0:
Press ‘0’ to start this demo which transmits an incrementing data message and repeats every 500ms.
If the board has jumper wires (not provided) to connect the transmitter outputs to the receiver inputs
the display will show both TX and RX data.
To simplify the transmit and receive demos below, command ‘t’ will be entered first which will
enable the HI-35850 Self-Test feature. This causes the transmitted messages to be internally looped
back internally to the receiver. This way no external jumper connections are required to loop the
transmitter output to the receiver inputs.
Press ‘t’ to enable Self-Test mode, press again to disable it.
> t
> Self-Test ON
To see RX data even without the jumpers press ‘t’ from the menu before entering this demo to put
the part into Self-Test mode. After pressing ‘t’ then press ‘0’ again. To exit demo 0, press ‘q’ to get
back to the main menu.
The console output will appear like this using Self-Test Mode:
Press 'H' for this help menu, or press any valid menu key. >>
t
Self-Test ON
> 0
Press 'q' to quit
Status Reg: 0x0009
Control Reg: 0x2000
Divisor Reg: 0x01

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TX 30 20 10 00
RX 30 20 10 00
TX 30 20 10 01
RX 30 20 10 01
TX 30 20 10 02
RX 30 20 10 02
TX 30 20 10 03
RX 30 20 10 03
TX 30 20 10 04
RX 30 20 10 04
Status Reg: 0x0009
Control Reg: 0x2000
Divisor Reg: 0x01
>
After ‘q’ is pressed the program stops and the Status register, Control Register and Division register
values are reported on the console.
Demo 1:
Press ‘1’ to load 32 messages in the transmit FIFO with an incrementing data pattern. Transmissions
should begin immediately and can be viewed with an oscilloscope on J5 or J6 pins 1 and 2.
To read the messages from the Receive FIFO press ‘3’.
t
Self-Test ON
> 1
TX FIFO 32 loaded
> 3
00 01 02 03
04 05 06 07
08 09 0A 0B
0C 0D 0E 0F
10 11 12 13
14 15 16 17
18 19 1A 1B
1C 1D 1E 1F
20 21 22 23
24 25 26 27
28 29 2A 2B
2C 2D 2E 2F
30 31 32 33
34 35 36 37
38 39 3A 3B
3C 3D 3E 3F
40 41 42 43
44 45 46 47
48 49 4A 4B
4C 4D 4E 4F
50 51 52 53
54 55 56 57
58 59 5A 5B
5C 5D 5E 5F
60 61 62 63
64 65 66 67
68 69 6A 6B
6C 6D 6E 6F
70 71 72 73

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74 75 76 77
78 79 7A 7B
7C 7D 7E 7F
>
Demo 2:
Press the ‘2’ key to transmit 8 messages with the incremental data pattern. Press ‘3’ to display the
messages.
Demo 3:
Press ‘3’ to read any existing RX FIFO messages and display them on the console. If there are no
messages in the FIFO there will be no output.
Demo 4:
Press ‘4’ to enter a programmed loop that reads any incoming RX messages and displays them on the
console. This will continue indefinitely until the ‘q’ key is pressed to exit.
Demo ‘t’: Self-Test Mode.
Press ‘t’ to alternate between Self-Test mode and Normal mode. This command sets or clears CR5 in
the Control Word.
Demo ‘c’: Cycle between the ACLK divisor selections listed in the data sheet.
Once this has been invoked the Divisor is in use. The Holt daughter card has an on-board 1MHz
oscillator so a divisor of 1 should be used. To use a 2, 4, 8 or 10MHz clock a jumper on the board can
be used to select between the 1MHz oscillator and an external clock applied to TP13. To disable the
divisor press the board reset. This feature could be used to configure the HI-35850 for 50KHz ARINC.
Using a 1MHz clock and selecting divisor 2 will configure the rate for 50KHz. The ARINC speed in the
control register must be set to high speed for this to work.
> c
ACLK Divisor: 1
> c
ACLK Divisor: 2
> c
ACLK Divisor: 4
> c
ACLK Divisor: 8
> c
ACLK Divisor: 10
> c
Demo ‘s’: Toggle ARINC 429 Speed.
Press ‘s’ to toggle between low speed and high speed ARINC on both the Receiver and Transmitter.
The programmed default is high speed.

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Demo ‘S’: Toggle ARINC 429 Speed.
Press ‘S’ to select a new SPI frequency. The programmed default is 12MHz. Enter two hex digits at the
prompt. The formula to calculate a new frequency is:
Freq = 48/value
>S(Upper case S)
SPI divisor enter two digs
06
8.000000 MHz
>
Demo for ARINC Label Recognition (filtering).
The HI-35850 Receiver has the ability to filter out messages based on the Label value of the ARINC
429 message. Normally this feature is off and is enabled by first writing to a 256 bit label look up table
using Opcode 0x06 then enabling the look up table by setting CR2 high in the Control Word. For more
detail on the operation of the Recognition filter refer to the data sheet. To use the feature the look
up table must be initialized before enabling CR2 otherwise un-initialized table contents will cause
unpredictable reception/filtering. When writing to the memory look up table all 256 bits must be
written. See Opcode 0x06 in the data sheet to see the bit order of the 256 memory how they relate
to the 8-bit Label field.
The ARINC 429 sequence as viewed on the bus. Notice the eight Labels bits occur first.
The SPI order of these bits when transferring messages to or from the Receive or Transmit FIFO’s:
Label Demo:
Pressing ‘m’ to read Label memory prior to writing to Label memory will typically show random or
0xFF’s values. Un-initialize label memory:
Labels 0-63: 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF
Labels 64-127: 0xBF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF
Labels 128-191: 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF
Labels 192-255: 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF
>

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Press ‘M’ (upper case) to write to Label memory from an pre-programmed array in the demo software.
This array is shown below:
unsigned char LabelArray[32] = {
// ---------------------------------------------------------------
// 255-248 247-240 239-232 231-224 223-216 215-208 207-200 199-191
0XEF, 0Xff, 0Xff, 0Xff, 0Xff, 0Xff, 0xff, 0xff, // label 255 rejected
// 191-184 183-176 175-168 167-160 159-152 151-144 143-136 135-128
0Xff, 0Xff, 0Xff, 0Xff, 0Xff, 0Xff, 0Xff, 0Xff,
// 127-120 119-112 111-104 103-096 095-088 087-080 079-072 071-064
0Xff, 0Xff, 0Xff, 0Xff, 0Xff, 0Xff, 0Xff, 0Xff,
// 063-056 055-048 047-40 039-032 031-024 023-016 015-008 007-000
0Xff, 0Xff, 0Xff, 0Xff, 0Xff, 0XFF, 0XFF, 0X55 }; // labels 1,3,5,7,rejected
Bits set high enables labels in that location and bits set low disables a label.
After pressing ‘M’ to write the look up table, press ‘m’ to show these values but in reverse order.
Labels 0-63: 0x55 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF
Labels 64-127: 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF
Labels 128-191: 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF
Labels 192-255: 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xEF
Press ‘l’ to enable Label reception so this label memory takes effect so filtering is enabled on received
messages. Messages that are enabled in the memory look up table will be loaded in the Receive FIFO,
others will be rejected. Command ‘l’ toggles the CR2 Enable Label Recognition bit high in the Control
Word the first time ‘l’ is pressed. To disable Label recognition press ‘l’ again.
When Label recognition is enabled this demo enables all messages where the Label memory had ones
written. Messages rejected are 255, 1, 3, 5 and 7 as indicated in the code comments.
IAR IDE and Holt Demo project installation
These steps are not required to perform the Quick Start operations just presented.
1. Installed IAR Systems Embedded Workbench for ARM (EWARM ) compiler is required BEFORE
adding the Holt demo project, so all Atmel board library files and the demo project folder are
created in the proper locations. Follow the “Holt HI-35850Demo Project Installation Guide” found
in the Project folder on the Holt CD-ROM. Before proceeding to the next steps IAR must be
installed and the Holt project folder must be in the proper folder location, according to that
guide. Instructions beyond this point assume you have completed the above installation
tasks. The Holt demo project requires IAR EWARM version 7.1 or greater. If using IAR 8.x versions,
another technical note is included which provides additional guidance.
2. Launch IAR Embedded Workbench from the Windows Start menu. A blank screen should appear.
Open the Holt HI-35850 Demo Project from the IAR File pull-down menu, click on
File/Open/Workspace and navigate to the project folder location and select “HI-35850
Demo.eww” and click the Open button.

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3. Debug requires an interface between the computer running IAR Embedded Workbench® and the
HI-35850 Application Development Kit. Connect the small end of the provided USB cable to the
evaluation board USB connector marked DEBUG. Connect the other end of the USB cable to a free
computer USB port. The IAR C-SPY Debugger for ARM includes drivers for numerous target system
interfaces, including built in “J-link On Board”.
The first time the evaluation board USB cable is connected to the computer, the Windows “Found
New Hardware” message should appear for the J-Link device. After several seconds, Windows
should load the appropriate driver and advise, “Your hardware is ready for use”. An internet connection
is required.
If difficulties arise when initiating a debug session at step 5, click Project then Options. In the
window that opens, under Category = Debugger highlight J-Link/J-Trace. Click the tab labeled
Connection, then verify Communications = USB and Interface = SWD.
4. Open IAR Embedded Workbench®. Click File, then Open Workspace, then navigate to the project
subdirectory created in step 4. Select the project file with .eww extension, then click Open. (The
next time Embedded Workbench® opens, this project will appear in the Recent Workspaces list
when File is clicked.)

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5. If problems occur with IAR installation or with using the IAR debugger, two Holt technical notes
are provided to help resolve these issues included on the Holt USB memory stick.
6. The demo project only uses unsigned integer variables. Optionally turn off the nuisance compiler
message that occurs when a variable’s most significant bit toggles. The message looks like this:
Remark[Pe068]: integer conversion resulted in a change of sign
To disable this diagnostic message, click Project then click Options
Category = C/C++ Compiler
Tab = Diagnostics
Suppress these diagnostics: add "Pe068" to list
7. RAM based projects are not supported due to the limited amount of RAM on the MCU. By
design the Cortex™-M3 runs slower in RAM than in Flash so there is little need for a RAM based
project. Compile the project by clicking the Make button. See following illustration. If the Build
messages window in IAR Embedded Workbench® indicates no errors or warnings, you can continue. If
errors occurred, correct them and recompile the program.
8. Initiate a debug session by clicking the Restart Debugger button. This downloads the compiled
program into the MCU and readies the board for program execution. Click Go to start execution.
Click Break (normally displayed during execution as a red upheld hand) to stop execution.

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HI-35850 SPI basics for troubleshooting
This is a brief tutorial on host SPI communication with the HI-35850. The first step in trouble shooting the
SPI is to read the Status Register and see if the expected value after reset is read; it should be 0x09.
To help facilitate this a preprogrammed sequence executes when the SW1 push button is pressed (on the
bottom board), the program performs three SPI sequences:
Reads the Status Register using Opcode 0x0A.
Writes the Control Register using Opcode 0x10.
Reads the Control Register using Opcode 0x0B.
When trouble shooting SPI issues the focus should be to read the Status Register using Opcode 0x0A and
review the value for clues to the problem. The nCE, CLK, SI and SO should look similar to the analyzer plot
shown below.
Final Tips for new host interfacing:
1. The preferred ACLK rate is 1MHz for minimal EMI considerations but it can be any even multiple of
two. See the data sheet for the available selections.
2. The Holt demo code attempts to read the power up Status Register value before continuing to display
the menu. This is used as a good IC indicator in the code at power up.
3. When installing IAR an internet connection is needed.
4. This demo board and software is compatible with the HI-3585 when the Demo0 DIP switch is in the
open position.
5. The Holt low level SPI drivers set nCS low during SPI access then high again at the end directly using a
GPIO pin configuration. It must be controlled by software for compatibility with the way Holt SPI
operates.

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Project File List with Selected Descriptions
HEADER FILES WITHOUT CORRESPONDING C FILES
driver_3585_850.c/h
Contains all macros for the HI-35850 including define statements
for registers, control register bits, Op Codes and selected table
start addresses. Host Cortex M3 SPI low-level SPI drivers and
messaging functions.
35850_initialization.h
Definitions for a few configuration settings including the INTERRUP_MESG_ENA macro used to
disable or enable interrupts in the demo.
HoltSupport.c/h
Host helper functions for configuring, table initialization
and transmitting and receiving ARINC messages. Some of
these functions may not be used in this demo.
main.c
The primary program entry and main loop in main().
Holt_Board.c
Contains macros for SPI initialization, LEDs and various I/Os.
Timer1 tick 1ms initialization supporting delay functions and host
timer interrupt handler. Board related to the host MCU.
Holt_Interrupts.c/h
Initialization and IRQ handler for message interrupts on the 35850 INT
pin. Functions to set or clear interrupt label enable table memory.
Demo.c ( these demos are called mostly from the console)
All demos are contained here. See the header file for a complete
listing.
console.c
Console functions used by all demos.
Show_menu(); displays the main menu
chk_key_input(); Key entry detect and demo execution handler.

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Application Development Kit Notes
The HI-35850 was designed for compatibility with microcontrollers or FPGAs having a Serial Peripheral
Interface (SPI). The minimal host interface could consist of just ACLK, SPI(4) and nMR.
The HI-35850 data transfer speed depends on the SPI clock frequency provided by the MCU SPI interface.
The ARM Cortex M3 MCU master clock frequency is 96MHz, using an internal PLL. MCU peripherals divide
this clock by two for a 48MHz clock source. The SPI block divides this by 4 for a 12MHz SPI clock rate which
is the maximum for the HI-35850. There is no lower frequency limit but most application should use at
least a 1MHz rate for reasonable performance.
The demo board includes a fully featured high-end USB debugger port. No additional debug tools are
required to rebuild the demo project and re-flash the ARM Cortex M3 processor.
Summary
The HI-35850 is a powerful ARINC 429 Transmitter and Receiver solution. Its high-speed 4-wire SPI
interface makes it easy to control with a minimum number signals. The demo program demonstrates most
aspects of the device and the low level C drivers make it easy to port to other platforms.

Holt Integrated Circuits, Inc.
PCB P/N: HV057
Bill of Materials
HI-35850 44-QFP
Evaluation Board
Rev. A
Item Qty Description Reference Digikey P/N Mfg P/N
1 1 PCB, Bare, Evaluation Board N/A NewTeck PCB# 18777
4 5
Capacitor, Cer 0.1uF 20% 50V Z5U 0805 C1,C8,C10,C11,C13 399-9157-1-ND Kemet C0805C104M5VACTU
4 1
Capacitor, Cer 1.0uF 16V X7R 0805 C5 399-1284-1-ND Kemet C0805C105K4RACTU
4 1
Capacitor, Cer 2.2uF 16V X7R C3, 445-7581-1-ND TDK C2012X7R1C225M125AB
4 2
Capacitor, Cer 4.7uF 16V X7R C2,C6 587-3312-1-ND TAIYO EMK212AB7475KGHT
4 4
Capacitor, Cer 10uF 16V X7R 0805 C7,C9,C12,C14 587-3319-1-ND TAIYO EMK212BB7106MG-T
7 2
Header, Male Vert 2x20, .1" Pitch J_3,J_4 S2011E-20-ND Sullins PBC20DAAN
7 2
Header, Male Vert 2x5, .1" Pitch J_5A,J_5B S2012EC-05-ND Sullins PBC05DAAN
8 7
Conn Header 2 Pin Male, .1" Pitch J1,J2,J3,J5,J6,J7,J8 S1011E-02-ND Sullins PBC02SAAN
8 1
Conn Header 9 Pin Male, .1" Pitch J10 S1011E-09-ND Sullins PBC09SAAN
8 1
Conn Header 3 Pin Male, R/A, .1" Pitch J9 S1111E-03-ND Sullins PBC03SBAN
8 1 Shunt 0.1" Pitch J9 Shunt S9000-ND Sullins STC02SYAN
11 1Res 51, 5% 1/8W 0805 SMD R15 P51ACT-ND Panasonic ERJ-6GEYJ510V
13 5
Res 330, 5% 1/8W 0805 SMD R5,R6,R7,R8,R9 P330ACT-ND Panasonic ERJ-6GEYJ331V
11 2
Res 40.2K,1% 1/8W 0805 SMD R12,R13 P40.2KCCT-ND Panasonic ERJ-6ENF4022V
11 1
Res 53.6K, 1% 1/8W 0805 SMD R2 P53.6KCCT-ND Panasonic ERJ-6ENF5362V
14 1
Res 100K 5% 1/8W 0805 R3 P100KACT-ND Panasonic ERJ-6GEYJ104V
11 1
Res 162K, 1% 1/8W 0805 SMD R1 P162KCCT-ND Panasonic ERJ-6ENF1623V
11 1
Res 402K,1% 1/8W 0805 SMD R4 P402KCCT-ND Panasonic ERJ-6ENF4023V
10 3
Led Green SMD 0805 LED1,LED2,LED3 160-1179-1-ND LiteOn LTST-C170GKT
10 1
Led Red SMD 0805 LED4 160-1178-1-ND LiteOn LTST-C170EKT
10 1
Led Orange SMD 0805 LED5 160-1177-1-ND LiteOn LTST-C170AGKT
1
Diode Schottky 40V 500mA SOD123 D1 B0540WQ-7-FDICT-ND Diodes B0540WQ-7-F
2
Inductor, 10uH 450mA 390mOhm L1,L2 490-4059-1-ND Murata LQH32CN100K53L
15 1
Switch Tape Seal 4 Pos SMD SW1 CT2194MST-ND CTS 219-4MST
16 9
Test Point, White Insulator, 0.040"
TP1,TP3,TP4,TP5,TP6,TP7,TP8
,TP9,TP10 Optional
36-5002-ND Keystone 5002
17 1
Test Point, White Insulator, 0.062" TP12 (ACLK) 36-5012-ND Keystone 5012
17 1
Test Point, Orange Insulator, 0.062" TP13(Ext_Clk) 36-5013-ND Keystone 5013
19 3
Test Point, Black Insulator, 0.062" TP2,TP11,TP15 36-5011-ND Keystone 5011
1
IC Reg Boost Adj LT3463A, 10-Pin DFN U1 LT3463AEDD#PBF-ND Analog LT3463AEDD#PBF
20 1
HI-35850 44-Pin QFP U2 HI-35850 HI-35850PQx
22 1 Xtal XO 1.0Mhz, 3.2x5mm 1.6-3.6V
OSC1 SER3937CT-ND Epson SG5032CAN 1.000000M-TJGA3