atwilc3000 bluetooth porting guide - microchip...

Atmel SmartConnect

ATWILC3000 Bluetooth Porting Guide

USER GUIDE

Introduction

This user guide describes the software deliveries of Atmel® ATWILC3000 Wi-Fi®/Bluetooth® combo chip

and the features it provides tested by the software.

Deliveries are tested against SAMA5D4 running Android KitKat 4.4.

Atmel-42562A-ATWILC3000-Porting-Guide_UserGuide_032016

ATWILC3000 Bluetooth Porting Guide [USER GUIDE] Atmel-42562A-ATWILC3000-Porting-Guide_UserGuide_032016 2

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Table of Contents

1 HCI Interface ................................................................................................................. 4

1.1 Introduction ............................................................................................................................................ 4 1.2 HCI Command Packet ......................................................................................................................... 4

1.3 HCI Event Packet ................................................................................................................................. 5

2 Vendor Specific HCI Commands ................................................................................ 6

2.1 Update UART Parameters Command ................................................................................................ 6

2.2 Change BD Address ............................................................................................................................ 6

2.3 Write Memory ....................................................................................................................................... 6

2.4 Vendor Specific Reset......................................................................................................................... 6

2.5 Read Register ...................................................................................................................................... 6

3 Firmware Download ..................................................................................................... 7

3.1 Using UART ......................................................................................................................................... 7

3.1.1 Detecting if Firmware is Downloaded or Not........................................................................ 7

3.1.2 Firmware is Already Downloaded ......................................................................................... 7

3.1.3 Start Firmware Download....................................................................................................... 7

4 ATMEL EVALUATION BOARD/KIT IMPORTANT NOTICE AND DISCLAIMER ........ 11

5 Revision History ........................................................................................................ 12

ATWILC3000 Bluetooth Porting Guide [USER GUIDE] Atmel-42562A-ATWILC3000-Porting-Guide_UserGuide_032016

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Icon Key Identifiers

Useful Tips and Techniques

Delivers Contextual Information About a Specific Topic

Note to Quality and Performance

Objectives to be Completed

Actions to be Executed Out of the Target

The Expected Result of an Assignment Step

Procedure Which Can Result in Minor Equipment Damage

Procedure With Potential Equipment Damage

Procedure With Imminent Equipment Destruction


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1 HCI Interface

Bluetooth (BT) uses standard HCI commands for communication between the host and BT controller. The

HCI commands are defined in the Bluetooth Specification Version 4.0.

1.1 Introduction

There are four kinds of HCI packets that can be sent via the UART Transport Layer:

HCI Command Packet

HCI Event Packet

HCI ACL Data Packet

HCI Synchronous Data Packet

Vendor specific commands utilizes the HCI Command Packet and the HCI Event Packet only as per the

following block diagram.

1.2 HCI Command Packet

The HCI Command Packet is used to send commands to the Controller from the Host. It has the following

structure.

Table 1-1. Generic HCI Command Structure

1 byte 2 bytes 1 byte n bytes

HCI Packet Indicator Op Code Parameters Length Parameters Payload

Table 1-2. Generic HCI Command Parameters

Parameter Description

HCI packet indicator This field is used to differentiate among the four HCI packets types, the value “1”

represents “HCI Command packet”

OP Code This field is used to determine the OP code of the HCI command

Parameters Length Length of the command required parameters in bytes

Parameters The required parameters for the HCI command

HCI HOST HCI

Controller

HCI Command

HCI Event


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1.3 HCI Event Packet

The HCI Event Packet is used by the Controller to notify the Host when events occur. The Host must be

able to accept HCI Event Packets with up to 255 bytes of data excluding the HCI Event Packet header.

Table 1-3. Generic HCI Event Structure

C 2 bytes 1 byte n bytes

HCI Packet Indicator Event Code Parameters Length Parameters Payload

Table 1-4. Generic HCI Event Parameters

Parameter Description

HCI packet indicator This field is used to differentiate among the four HCI packets types, the value “4”

represents “HCI Event packet”

OP Code Each event is assigned a 1-byte event code used to uniquely identify different

types of events

Parameters Length Length of the event parameters in bytes

Parameters The required parameters for the HCI event


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2 Vendor Specific HCI Commands

Some non-standard HCI commands are being used by the ATWILC3000 BT core to provide extended

services and options for the host.

2.1 Update UART Parameters Command

In case the host needs to change the UART settings of the BT controller, it can use this command to

change the baud rate and flow control options.

Table 2-1. Update UART Parameters Command Structure


1 0xFC53 5 Baud rate (4bytes) Flow control (1byte)

2.2 Change BD Address

If the BD address is not stored on the BT controller’s side, the host can use this command to update the

BD address. After issuing this command, a standard Reset Command (Op Code 0x0c03) should be

issues for the new address to apply.

Table 2-2. Change BD Address Command Structure


1 0xFC54 6 BD Address (6 bytes)

2.3 Write Memory

This command is used when the Boot ROM is running on the host controller only to write a block of

memory to the BT controller. Its main function is to download the firmware to the controller.

Table 2-3. Write Memory Command Structure

HCI Packet

Indicator

Op Code Parameters

Length

Parameters Payload Data Block

1 0xFC52 8 Address (4 bytes) Size (4 bytes) Data block to be written to the memory

2.4 Vendor Specific Reset

This command is used when the Boot ROM is running on the host controller only. It should be issued after

a new firmware is downloaded to the BT controller’s memory to start it.

Table 2-4. Change BD Address Command Structure


1 0xFC55 0 N/A

2.5 Read Register

This command is used to read registers from the BT controller using UART.

Table 2-5. Read Register Command Structure


1 0xcFC01 6 Register Address (4 bytes) 0x20 0x01


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3 Firmware Download

3.1 Using UART

The BT controller has a Boot ROM that starts execution as soon as the device is powered up. It can be

used to receive the firmware and download it to the instruction memory and trigger the controller to start

executing it. The Boot ROM runs initially at baud rate 115200bps, and flow control disabled.

3.1.1 Detecting if Firmware is Downloaded or Not

The host would know if the firmware is downloaded or not to decide whether it has to download a new

firmware or not. The detection is done by reading the local version through the standard Read Local

Version HCI command (Op Code 0x1001) and checking for byte number “7” in the HCI event packet sent

back from the BT controller as follows:

If byte 7 is 255 then the Boot ROM code

If byte 7 is 6 then the replying code is the firmware code

3.1.2 Firmware is Already Downloaded

In case the firmware is already downloaded, the host can follow the following sequence:

Change the UART parameters like the baud rate and flow control options

Change the BD address of the BT controller if the BD address is not stored on the controller

Send a reset command. This is mandatory in case the BD address was changed.

3.1.3 Start Firmware Download

The download process goes through the following steps:

1. Send standard Reset command (Op Code 0x0c03) to the controller.

2. Raise the controller baud rate to a higher baud rate to speed up the download process, this step is

done by issuing the vendor specific Update UART Parameters Command to the controller with the

required baud rate. It is better to keep flow control disabled at this point.

3. Raise the host baud rate to a matching baud rate.

4. Start downloading the firmware image to the controller IRAM starting at address “0x80000000”

through the Write Memory vendor specific HCI commands.

5. Send Vendor Specific Reset HCI command to transfer the execution from the Boot ROM code to

the downloaded firmware code.

6. Update the host UART’s baud rate and flow control setting to the initial settings that the firmware

operates at to be able to communicate with it.

7. Raise the controller baud rate and flow control settings to the required runtime operational settings.

8. Raising the host UART settings to matching settings.

9. Change the BD Address of the controller if the BD address is not stored on the BT controller.

10. Send standard HCI reset command to the controller to let it operate with the new BD Address.


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It is best when the firmware is downloaded to use a baud rate of 115200bps and to have flow control disabled by default. The Boot ROM uses these settings by default. This way the host can start its state ma-chine on the same UART settings whether the Boot ROM or the firm-ware is running on the controller, and will avoid any confusion that might occur. After the host’s state machine initializes and discovers whether it is communicating with the Boot ROM or the firmware, the host can use the vendor specific state machine to adjust the baud rate as needed. In this case, the host should take care of bringing the con-troller’s UART settings back to 115200bps and no flow control before it returns to the point where it needs to identify the entity running on the BT controller, if the BT controller will not power down.

When updating the Boot ROM’s baud rate, the Boot ROM might set its

baud rate to double the given baud rate. This happens when the con-

troller’s clock is updated from the Wi-Fi side for example, which results

in doubling the number of clocks on which the UART block bases the

baud rate. As a workaround, the host can update the Boot ROM’s baud

rate, then, change its UART settings to half this rate. To detect this

case, the host can read register 0x40001028 using the Read Register

vendor specific HCI command. If the value returned is 0x3, it needs to

apply the described workaround.


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Figure 3-1. BT Firmware Download Process Flow Chart

Is Boot ROM?

Change BD Address

No

Reset

Change UART Settings

End

Start

Reset

Yes

Download FW to the IRAM

No

Use higher baud rate for download?

YesAre clocks doubled?

Raise BT controller’s baud rate to

dwnload_baudrate/2

Raise BT controller’s baud rate to

dwnload_baudrate

Yes

No

Change host baudrate to

dwnload_baudrate

Reset BT controller using vendor

specific Reset HCI command

Power Save

For BT, a special behavior must to be implemented on the host side to inform the BT controller that it is

allowed to sleep. This happens by forcing a break signal on the host’s UART TXD line (de-asserting the

TXD line). The BT controller will respond by setting its RTS line high to prevent from the host from issuing

further communication until the controller is ready. This requires the flow control to be enabled in case BT

power save is in use.


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To issue more HCI commands to the BT controller, the host should exit the break condition, and wait for

the BT controller to set its RTS line low again, indicating readiness to receive commands.

The following timing diagram shows the BT controller’s behavior when it’s in sleep mode while the host

has a command to send:

Yellow: Host UART TXD

Blue: BT Controller UART TXD

Purple: BT Controller RTS

Figure 3-2. BT Wakeup Sequence Timing Diagram


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4 ATMEL EVALUATION BOARD/KIT IMPORTANT NOTICE AND

DISCLAIMER

This evaluation board/kit is intended for user's internal development and evaluation purposes only. It is

not a finished product and may not comply with technical or legal requirements that are applicable to

finished products, including, without limitation, directives or regulations relating to electromagnetic

compatibility, recycling (WEEE), FCC, CE or UL. Atmel is providing this evaluation board/kit “AS IS”

without any warranties or indemnities. The user assumes all responsibility and liability for handling and

use of the evaluation board/kit including, without limitation, the responsibility to take any and all

appropriate precautions with regard to electrostatic discharge and other technical issues. User indemnifies

Atmel from any claim arising from user's handling or use of this evaluation board/kit. Except for the limited

purpose of internal development and evaluation as specified above, no license, express or implied, by

estoppel or otherwise, to any Atmel intellectual property right is granted hereunder. ATMEL SHALL NOT

BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMGES RELATING

TO USE OF THIS EVALUATION BOARD/KIT.

ATMEL CORPORATION

1600 Technology Drive

San Jose, CA 95110

USA


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5 Revision History

Doc Rev. Date Comments

42562A 03/2016 Initial document release.


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Atmel Corporation 1600 Technology Drive, San Jose, CA 95110 USA T: (+1)(408) 441.0311 F: (+1)(408) 436.4200 │ www.atmel.com

© 2016 Atmel Corporation. / Rev.: Atmel-42562A-ATWILC3000-Porting-Guide_UserGuide_032016. Atmel®, Atmel logo and combinations thereof, Enabling Unlimited Possibilities®, and others are registered trademarks or trademarks of Atmel Corporation in U.S. and other countries. ARM®, ARM Connected® logo, and others are the registered trademarks or trademarks of ARM Ltd. Other terms and product names may be trademarks of others. DISCLAIMER: The information in this document is provided in connection with Atmel products. No license, express or implied, b y estoppel or otherwise, to any intellectual property right is granted by this document or in connection with the sale of Atmel products. EXCEPT AS SET FORTH IN THE ATMEL TERMS AND CONDITIONS OF SALES LOCATED ON THE ATMEL WEBSITE, ATMEL ASSUMES NO LIABILITY WHATSOEVER AND DISCLAIMS ANY EXPRESS, IMPLIED OR STATUTORY WARRANTY RELATING TO ITS PRODUCTS

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