Bluetooth HID Profile Manual Datasheet by Microchip Technology

MINIMUM}- Bluetooth HID Profile

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RN-HID-UM

Bluetooth HID Profile

USER MANUAL

RN-HID-UM Version 1.1r 3/13/2012

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OVERVIEW

Roving Networks Bluetooth modules support a variety of Bluetooth profiles, including human interface device

(HID), serial port profile (SPP), DUN, HCI, and iAP for use with iPad, iPod and iPhone devices. The Bluetooth HID

profile enables customers to develop wireless products such as computer keyboards and keypads, trackballs,

mice, and other pointing devices, and game controllers (gamepads, joysticks, steering wheels, etc.). Additionally,

Roving Networks has extended the basic HID capability to allow programmability and control of devices such as

the iPad.

The HID (Human Interface Device) profile defines the protocol between:



Device (HID)

—Services human data input and output to and from the host.



Host

—Uses or requests the services of a Human Interface Device.

The Bluetooth HID profile allows users to control the HID descriptor, which defines the device’s feature set, and

the HID report, which host uses to interpret the data as ASCII values, movement, etc. The HID report format

follows the standard universal serial bus (USB) HID protocol as to leverage existing host drivers.

NOTE: This user manual focuses specifically on HID. The Roving Networks Bluetooth

Advanced User Manual

and

Apple User Manual

cover the functionality of all supported Bluetooth profiles. Because the HID

profile is derived from Roving Network’s standard firmware, many of the concepts and commands

found in the

Advanced User Manual

apply as well.

In a typical usage scenario such as a keyboard, a device using the Roving Networks Bluetooth HID profile

replaces the USB cable. In this case, the ASCII value of a key press is converted to a scan code in a raw HID

report that the Bluetooth module sends over the Bluetooth link to the host. The host driver software decodes

the raw HID report and passes the key values to the application running on the PC. Figure 1 shows some typical

HID environments.

Figure 1. Typical HID Environments

The type of HID device, such as a keyboard, mouse, or joystick, is defined by the HID descriptor in the raw HID

report.

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FIRMWARE OVERVIEW

To use Roving Networks’ Bluetooth HID profile, you must use a special build of firmware, version 6.03 or later.

When you purchase a Roving Networks Bluetooth product, you must specify that you wish to use this firmware

version so that Roving Networks can load it into the module. The part numbers for ordering modules with the

HID profile are RN-41-HID and RN-42-HID.

NOTE: This user guide assumes the reader has an understanding of Roving Networks standard Bluetooth

firmware ASCII command interface and command set. It is strongly recommended that you refer to

the Bluetooth

Advanced User Manual

prior to reading this document.

Operational Modes

Roving Networks Bluetooth modules operate in two modes: data mode (default) and command mode. While in

data mode, the module is essentially a data pipe. When the module receives data, it strips the Bluetooth headers

and trailers and passes the user data to the UART. When data is written to the UART, the module constructs the

Bluetooth packet and sends it out over the Bluetooth connection. Thus, the entire process of sending/receiving

data to the host is transparent to the end microprocessor.

You configure the module by putting it into command mode and sending ASCII commands over a serial port or

the Bluetooth link. Once you change the configuration parameters, they persist until changed or you perform a

factory reset. You enter command mode by opening a terminal emulator and sending the string $$$ to the

module. You can connect to the module remotely over Bluetooth or via a computer. When you send $$$ the

module returns CMD, indicating that it is in command mode.

Once the module is in command mode, you can send configuration commands to it via the terminal. When you

enter a valid command, the adapter returns AOK. It returns ERR for an invalid command and ? for unrecognized

commands. Type h <cr> to see a list of commands, and d <cr> to view a summary of the adapter’s current

settings. To return to data mode, type --- <cr> or reset the device and re-connect.

Profile Configuration

The HID firmware supports Bluetooth HID and SPP. You switch between these profiles using ASCII commands. In

firmware version 6.10 and higher, the SPP profile is enabled by default. There are two ways to switch the

profile.

1. Using PIO 11: On power up PIO 11 is sampled and if HIGH, HID profile is selected. Otherwise the profile

stored in flash is used (requires bit 9 to be set in the HID flags register. This is set by default).

2. Using command mode: To switch between HID and SPP, use the following commands:

S~,6 // Enables HID profile

R,1 // Reboot to use HID profile

To switch back to SPP, use the following command:

S~,0 // Enables SPP protocol

R,1 // Reboot to use SPP

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Device Discovery & Pairing

Since the Roving modules default to SPP, they will show up as “FireFly-ABCD” upon power up, where ABCD are

the last four digits of the MAC address. However, if the profile is changed to HID using the commands described

above, the modules default to a HID keyboard and is discoverable with the name “FireFly-ABCD”, where ABCD

are the last four digits of the MAC address. You can change the device type by setting the descriptor type using

the HID flags register.

After first pairing the host to a device with the Bluetooth HID module, the host initiates a connection. However,

if the initial connection is broken, as the case when the power is cycled, the device must re-connect to the host.

(The host will not initiate a connection.)

Using DTR mode 4 (default) or pairing mode 6 allows the module to auto-connect back to the last paired host.

Alternatively, you can reconnect by sending the C command from command mode.

Quiet Mode

Quite mode causes the device to be non-discoverable and non-connectable temporarily. This command does not

survive power cycle.

With firmware version 6.10 and higher, the Q command now has 3 settings that have different responses as

follows:

Q,0 // The module is discoverable and able to connect

Q,1 // The module is not discoverable and not able to connect

Q,2 // The module is able to connect but is not discoverable

Authentication

With firmware version 6.10 and higher, SA is 2 bits. It can have the values 0, 1, 2, or 4, depending on the mode

desired.

SA,0 // With this mode, the module uses Bluetooth version 2.0 NO encryption (open mode). This

mode is useful for legacy devices that do not need security. This mode is the same as in

firmware version 4.77. For this mode to work, both devices must support open mode. If either

device requests authentication, the PIN code will be required.

SA,1 // In Bluetooth version 2.1, the default is keyboard I/O mode (which is considered as a secure

mode). For Android devices, the user is prompted with a 6-digit code and is asked to verify

that the code matches on the module. Because the module cannot display a code, simply press

OK or Yes on the remote device to authenticate.

SA,2 // This mode corresponds to Bluetooth version 2.1 Secure Simple Pairing (SSP), or just works

mode. This mode works with iPhones and PCs, however it may not work appropriately with

some Android devices.

SA,4 // This mode is PIN code mode, which forces Bluetooth version 2.0 PIN code authentication.

The functionality is similar to firmware version 4.77.

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Encryption

In firmware version 6.10 and higher, encryption is always enabled. In prior versions of firmware, you used the SE

command to turn on encryption. Refer to “Creating a Custom UUID” for more information on the SE command

functionality in firmware version 6.10 and higher.

Creating a Custom UUID

In firmware version 6.10 and higher, the SE command, SE,<

1 – 16

>, is used to set the UUID (E stands for

extended UUID). The GE command displays the extended UUID.

This feature applies to Roving Networks’ modules when configured in SPP profile mode. Using this feature the

Roving Modules can connect back to the remote device when it is range. This features is used primarily for

smartphones and tablets based on Android OS.

With this feature, you can set a custom UUID for connecting back to an Android device. Android phones run an

audio gateway that always attempts to grab a connection when it comes in from a remote Bluetooth device such

as the Roving Networks module. With the SE command, you can register a custom UUID, which ensures that

ONLY your app on the Android device obtains the connection when it comes in.

The default SSP UUID is 0000110100001000800000805F9B34FB

You can modify a subset of the UUID; the bytes are changed from left to right. For example, if the UUID is:

0000110100001000800000805F9B34FB

Typing the command SE,ABCD <cr> changes the first 2 bytes resulting in:

ABCD110100001000800000805F9B34FB

The command has three short forms:

SE,S // Loads the default SPP UUID = 0000110100001000800000805F9B34FB

SE,I // Loads the iPhone UUID = 00000000DECAFADEDECADEAFDECACAFE

SE,C // Loads the custom UUID = EE286EA0000111E1BE500800200C9A66

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HID Flag Register

The HID flag register is a bit-mapped reregister that is configured while in command mode. To set the register,

use the SH, <

value

> command, where <

value

> is a 4-character hex word. The GH command returns the current

value of the register. The default factory setting is 0200, which corresponds to a keyboard.

Table 1 shows the HID flag register bits; currently only the lower 9 bits are defined.

Table 1. HID Flag Register Bits

9

8

7..4

3

2..0

Force HID mode if

GPIO11 is high on

power-up.

Toggle virtual

keyboard on iOS

when first

connected.

Descriptor type:

0 = Keyboard

1 = Game Pad

2 = Mouse

3 = COMBO

4 = JOYSTICK

5 = DIGITIZER

6 = SENSOR

7 = USE CFG

8-16 = Reserved

Send output reports

over UART.

Indicates number of

paired devices to which

the module can

reconnect.

Bit 9

Bit 9 is an enable bit that overrides the profile selection mode. When this bit is set, the firmware checks the level

of GPIO11 on power up; if it is high, the module switches to HID mode. With this bit, you can set the module’s

default profile to SPP mode, allowing SPP and remote configuration (for example from Bluetooth clients with

SPP). Then, you can use GPIO11 to override SPP mode and enable HID mode.

Bit 8

Bit 8 enables the toggling of the virtual keyboard on iOS devices.

Bits 7-4

Bits 7 through 4 control the following settings:

 The COD that is advertised by the module.

 The HID report descriptor and the available reports.

Bit 3

Bit 3 enables output reports, which are sent by the host to the device over Bluetooth to the UART. These reports

are a feedback mechanism to the embedded microcontroller. The output record is formatted as:

<

start

>

<

number of

bytes

>

<

report

>

0xFE

1 – 8

data

For example, the HID keyboard output reports the keyboard LED status as:

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0xFE 0x2 0x1 <

LED status byte

>

Bits 2-0

Bits 2 through 0 define the number of paired hosts to which the module attempts to reconnect after power up.

After each successful pairing, the link key is stored in the Bluetooth module. Up to eight paired link keys are

stored in FIFO fashion. Upon power up, the module tries to connect to the most recently paired device. If it is

not found, the module attempts to connect to the next

N

hosts depending upon the settings of bits 2-0 in the

HID register.

For example:

 To set the device as a mouse, use SH,0220.

 To set the device as a combo device (keyboard + mouse + consumer) , use SH,0230.

HID REPORTS

The module interprets input on the UART and generates an HID report that is sent over the Bluetooth link to the

host. Input to the module is interpreted as shown in Table 2.

Table 2. Data Interpretation

Binary Input

Function

0

Disconnect if connected from the host.

0x1 - 0xF

Converted to special keys like home, page up, backspace, etc.

0x10 - 0x7E

Translation mode: printable ASCII characters.

0x7F

Toggle virtual keyboard on iPhone.

0x80 - 0xDF

Interprets input as actual scan code.

0xE0 - 0xE7

Sends modifier keys Left Shift, Left Alt, Right Shift, etc.

0xE8 - 0xEF

Interprets input as actual scan code.

0xF0 - 0xFC

Reserved for custom reports.

0xFD

Raw mode: input is RAW report.

0xFE

Interpretive mode: input is shorthand report.

0xFF

Sends output report to UART.

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Raw Report Mode

The start byte 0xFD indicates a raw HID report. In the Bluetooth module, the start byte is stripped and the

following bytes are sent without interpretation. The Raw HID report consists of a start byte, length, descriptor

type (which defines the type of HID device), and data specified in scan codes or encoded values. The format of

the data depends on the descriptor type. HID reports are sent one report at a time.

The raw report format is:

Start

(1Byte)

Length

(1 Byte)

Descriptor

(1 Byte)

Data

Length – one Byte for the descriptor

The keyboard report format is:

0xFD

9

1

Modifier

0x00

Scan

code 1

Scan

code 2

Scan

code 3

Scan

code 4

Scan

code 5

Scan

code 6

The modifier byte is a bit mask interpreted as shown below. For example, you can use 0x2 or 0x20 to turn a

lower case a into an upper case A.

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Right

GUI

Right

Alt

Right

Shift

Right

Ctrl

Left

GUI

Left

Alt

Left

Shift

Left

Ctrl

The mouse raw report format is:

0xFD

5

2

Buttons

X-stop

Y-stop

Wheel

The consumer report format in keyboard or combo mode is:

0xFD

3

Data Byte

The joystick format is:

0xFD

6

Not used

Buttons

X1

Y1

X2

Y2

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In combo mode, it is possible to send both for a keyboard and mouse HID reports. In this case, if you wanted to

enter an A and move the mouse you can use either of the following methods:

A:

0XFD

0x05

0x02

0x00

0x20

0x00

or

0xFD

0x9

0x1

0x2

0x0

0x04

0x0

0XFD

0x5

0x2

0x00

0x20

0x00

HID Translation Mode

Translation mode is the simplest way to send HID reports for printable ASCII characters. When the Bluetooth

module’s UART receives a printable ASCII value, it is converted into a keyboard raw HID report. Two reports are

sent for each character; the first report indicates that the key is pressed and the second indicates that it is

released. For example:

a is translated into :

0xFD

0x09

0x01

0x00

0x04

0x00

Key Press

0xFD

0x09

0x01

0x00

Key Release

A is translated into:

0xFD

0x09

0x01

0x02

0x00

0x04

0x00

Key Press

0xFD

0x09

0x01

0x00

Key Release

Notice that the scan code for A is the same as the previous raw report except the modifier byte indicates the left

Shift key is pressed. If multiple scan codes are sent, the modifier applies to all of them.

Keyboard Shorthand Mode

The Roving Networks HID profile supports shorthand for implementing keyboards. The advantage of this mode

is that multiple keyboard keys can be sent with minimal characters over the UART, which optimizes bandwidth

because the module does not have to send a keyboard report. Shorthand reports start with 0xFE and have

variable length. The shorthand format is:

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0xFE

Length

Modifier

Scan

Code 1

Scan

Code 2

Scan

Code 3

Scan

Code 4

Scan

Code 5

Scan

Code 6

where Length = 0, 2, 3, 4, 5, 6, or 7, depending on how many keys are sent.

For example, shorthand for the a, b, and c keys is:

0xFE

0x04

0x00

0x04

0x05

0x06

This equivalent to a raw HID report of:

0xFD

0x09

0x01

0x00

0x04

0x05

0x06

0x00

Shorthand to release all three keys is:

0xFE

0x0

Special Reports & Modes

This section describes special modes and reports, including output reports, virtual keyboards, a key-map register,

etc.

Output Reports

Because the host controls the modifier keys’ state, the HID device must be able to request the current status.

The output report code 0xFF is reserved to return the current status of the Caps Lock, Num Lock, and Scroll Lock

keys over the UART. Because an HID device can only toggle these keys, it tells the device the state of the keys.

This functionality is particularly useful when multiple HID devices are in the system and the Bluetooth device

needs to update the state of these keys. The format is sent as:

0xFF

Status

Byte

Table 3 shows the status byte definitions.

Table 3. Status Byte Definitions

Key

Status Bit

Num Lock

1

Caps Lock

2

Scroll Lock

4

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Apple Virtual Keyboard

When the module is connected to an iOS device, the virtual keyboard is hidden. However, in some applications it

is useful or required to display the keyboard for data entry on the touch screen of the iOS device. Toggling

GPIO9 displays or hides the virtual keyboard. GPIO9 must go from low to high for at least 200 ms for the toggle

to occur.

NOTE: The virtual keyboard toggle must be enabled in the HID flag register for this feature to work.

Key Map Register

This register allows you to replace any ASCII code with another ASCII code. It is useful in cases where you want

to toggle special keys that the device cannot generate. For example, the touch keyboard on an iOS device is

0x7F, but the device cannot generate 0x7F.

If the register is non-zero, the upper byte is the key to replace, and the lower is the replacement. The command

to set the register is S=, <

value

>, where <

value

> is a 4-character hex word. To obtain the current value of the

register, use the G= command. (The value also shows up in the advanced settings using the E command.) The

default factory setting is 0000 (not enabled).

For example, to use the tilda (~), which is 0xfe, to toggle the keyboard, enter the command S=,7e7f.

Disconnect Key

A special hex key value 0x00 (zero) causes a Bluetooth disconnect, which allows you to control the connection

by sending a single key. To disconnect, send 0x0.

Combining the disconnect feature with the key map register, any key can be used as a disconnect key. For

example to set the capital Z key (hex 5A) as the disconnect key, use the following command:

S=,5A00 // Map Z key as the disconnect key

Consumer Report

You can use a HID raw report to send additional keys as a consumer report. The format is:

0xFD

3

Low Byte

High Byte

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Table 4 shows the data byte format.

Table 4. Data Byte Format

Consumer Key Function

Report Bit

AC Home

0x1

AL Email Reader

0x2

AC Search

0x4

AL Keyboard Layout (Virtual Apple Keyboard Toggle)

0x8

Volume Up

0x10

Volume Down

0x20

Mute

0x40

Play/Pause

0x80

Scan Next Track

0x100

Scan Previous Track

0x200

Stop

0x400

Eject

0x800

Fast Forward

0x1000

Rewind

0x2000

Stop/Eject

0x4000

AL Internet Browser

0x8000

For example, to raise the volume, send:

0xFD

0x03

0x10

0x00

To release the key, send:

0xFD

0x03

0x00

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SCAN CODE TABLES: UART (ASCII) TO HID REPORT

Table 5 shows the UART-to HID input conversion.

Table 5. UART-to-HID Scan Code

UART Input

HID Code

HID Function

0

NA

Disconnect if Connected

1

0x49

Insert

2

0x4A

Home

3

0x4B

Page up

4

0x4C

delete

5

0x4D

end

6

0x4E

Page down

7

0x4F

Right arrow

8

0x2A

Backspace

9

0x2B

TAB

10

0x28

Enter

11

0x50

Left arrow

12

0x51

Down arrow

13

0x28

Enter

14

0x52

Up arrow

15-26

0x3A-45

F1 - F12

27

0x29

Escape

28

0x39

Caps lock

29

0x47

Scroll lock

30

0x48

Break-pause

31

0x53

Num lock

32-126

Printable ASCII characters

127

0x65

Toggle iPhone virtual keyboard

0x80-0xDF

Sends actual scan code

0xE0

Left Control

0xE1

Left Shift

0xE2

Left Alt

0xE3

Left GUI

0xE4

Right Control

0xE5

Right Shift

0xE6

Right Alt

0xE7

Right GUI

0xE8-0xEF

Sends actual scan code

0xF0-0xFC

Reserved for future

Custom reports

0xFD

Raw report

0xFE

Shorthand report

0xFF

Sends output report to UART

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Table 6 shows the ASCII to HID scan codes.

Table 6. ASCII to HID Report (to Host) Scan Codes

ASCII

Code

ASCII

Code

ASCII

Code

ASCII

Code

System Power

81

m M

10

6 ^

23

. >

37

System Sleep

82

n N

11

7 &

24

/ ?

38

System Wake

83

o O

12

8 *

25

Caps Lock

39

No Event

00

p P

13

9 (

26

F1

3A

Overrun Error

01

q Q

14

0 )

27

F2

3B

POST Fail

02

r R

15

Return

28

F3

3C

ErrorUndefined

03

s S

16

Escape

29

F4

3D

a A

04

t T

17

Backspace

2A

F5

3E

b B

05

u U

18

Tab

2B

F6

3F

c C

06

v V

19

Space

2C

F7

40

d D

07

w W

1A

- _

2D

F8

41

e E

08

x X

1B

= +

2E

F9

42

f F

09

y Y

1C

[ {

2F

F10

43

g G

0A

z Z

1D

] }

30

F11

44

h H

0B

1 !

1E

\ |

31

F12

45

i I

0C

2 @

1F

Europe 1

32

Print Screen

46

j J

0D

3 #

20

; :

33

Scroll Lock

47

k K

0E

4 $

21

‘ “

34

Break (Ctrl-Pause)

48

l L

0F

5 %

22

, <

36

Pause

48

REFERENCES

[1] Bluetooth SG, Human interface Profile overview

URL: https://www.bluetooth.org/Building/HowTechnologyWorks/ProfilesAndProtocols/HID.htm

[2] USB.org, HID usage tables

URL: http://www.usb.org/developers/devclass_docs/Hut1_12v2.pdf

[3] USB.org, HID technology

URL: http://www.usb.org/developers/hidpage/

RESOURCES & RELATED DOCUMENTS

For more information, refer to the following sources, which are available on the Support page on the Roving

Networks website at http://www.rovingnetworks.com/support.php:



Bluetooth Advanced User Manual



iAP Bluetooth Evaluation Kit for Developing Accessories Compatible with iOS Devices User Manual

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KNOWN ISSUES

The HID profile does not seem to always work with the BlueSoleil stack.

RELEASE NOTES

Version 6.10 2/17/12

 Added additional functionality to the Q command to enable/disable device discovery and ability to

connect.

 Added authentication modes: open mode, keyboard mode, SSP mode, and PIN code mode.

 Encryption is enabled by default and cannot be disabled.

 Added the ability to store a custom UUID in the device.

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NOTES

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Roving Networks, Inc.

102 Cooper Court

Los Gatos, CA 95032

+1 (408) 395-5300

www.rovingnetworks.com

a registered trademark of Roving Networks. Apple Inc., iPhone, iPad, iTunes,

Made for iPhone are registered trademarks of Apple Computer.

Roving Networks reserves the right to make corrections, modifications, and

other changes to its products, documentation and services at any time.

Customers should obtain the latest relevant information before placing

orders and should verify that such information is current and complete.

Roving Networks assumes no liability for applications assistance or

customer’s product design. Customers are responsible for their products and

applications which use Roving Networks components. To minimize customer

product risks, customers should provide adequate design and operating

safeguards.

Roving Networks products are not authorized for use in safety-critical

applications (such as life support) where a failure of the Roving Networks

product would reasonably be expected to cause severe personal injury or

death, unless officers of the parties have executed an agreement specifically

governing such use.

Bluetooth HID Profile Manual Datasheet by Microchip Technology

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