Smart Bluetooth Forum Discussions

BCM20732S, BCM20737S reflow parameter question

Solved

BCM20732S and BCM20737S data sheet state max. reflow temp = 245°Cbut process needs 250°C.Can Broadcom confirm 250°C reflow temperature is possible? Show More

By Anonymous

Mar 30, 2015

518

Smart Bluetooth

max escape time of fine timer

Solved

Hi All,So far, as we knew the fine timer is the SW timer and was driving by App thread and we have to use the timer to implement loop.We require to ha... Show More

By Anonymous

Apr 1, 2015

492

Smart Bluetooth

Hardware Design between 2073X and External MCU

External MCU Design PurposeBCM2073X is a great SoC for most of IoT/wearable products.But an external MCU may be needed for more complicated use case s... Show More

External MCU Design Purpose

BCM2073X is a great SoC for most of IoT/wearable products.But an external MCU may be needed for more complicated use case such as smart watch on which there are LCD, camera etc. This article is a guide on hardware design between BC2073X and external MCU.

System Architecture Introduction

Architecture Diagram

The following Figure shows the usual connection between MCU and BCM2073X chip, together with some other devices.

Fig1

The Interconnection BUS between MCU and BCM2073X

There are at least five interconnection bus needed between MCU and our BCM2073X chip: UART RX/TX, RESET, INT, and Wake up signals.

UART RX/TX buses are recommended to do data communication work, like notification status reporting data, external sensors inputting data, LCD display data, camera image data etc.

A reset signal from MCU to BCM2073X chip is used to give a reset signal when BCM2073X chip starts
up, or at any time when BCM2073X work abnormally.

An INT signal is an interruption from BCM2073X chip to MCU. For the occasion when MCU is in sleep mode, there are incoming calls,
messages, alarm or other notifications from the smartphones, tablets or other smart devices, which are connected with our BCM2073X chip through Bluetooth4.0/4.1. BCM2073X chip delivers these messages to MCU once it gets them, so that MCU can manage the related external devices to make the related response.The related response includes turning on or off LCD/LED/Vibrator/buzzer, etc., we can see the related devices showed on the above Fig.

A wake up signal is critical to MCU to wake up BCM2073X chip, when BCM2073X is in sleeping mode. For example when there are inputs from sensors, MCU will send a dedicated status update to BCM2073X after calculation, and BCM2073X chip pass them to the smart device for notifying the end user.

SW Download/Debugging Interface

SW downloading and debugging interface is located in MCU side, the software download interface can be UART or USB. This is determined by the MCU chip we choose. Ask support from MCU vendor for detailed download method.

The debugging interface can be shared with the download UART interface, or other ports. It’s also determined by MCU chips.

RF Testing Interface

We can do RF testing by separately controlling BCM2073X chip to enter into a testing mode by using Broadcom MBT tool. For HW, we connect BCM2073X chip UART RX/TX pin with a computer’s RS232 port. A level shift is needed for keeping the voltage of the two side at the same level, usually 5V voltage level from the computer side, a Vx(for BCM2073X chip, the voltage range is1.6-3.6V, the dedicated value of Vx is determined by BCM2073X, MCU and all the other device) voltage level from the board side. We can also have another simple way to add a USB to COM converting chip to connect BCM2073X UART RX/TX pin on the PCB board with the computers by common USB bus. Please refer the picture below for the detail physical connection between the instruments and the tested device.

For the detailed testing procedures we can refer to the application notes of BLE RF Testing Setup Procedures.

Of course, we have some other methods to do the RF testing, since the extra MCU is the master chip of the whole board, we choose MCU UART interface for commands inputting interface, the dedicated testing commands were sent by the putty or hyper terminal tool passing MCU UART interface to control BCM2073X chip, of course the detailed controlling way mostly rely on the MCU system used; or we also can have another method to integrate the dedicated testing commands into the source code of MCU system side, downloading into the memory on the board, a special testing tool can be added in a APK tool of the smart device in the far end, the special commands of APK tools trig the different testing mode of BLE chip, let the testing work going on by the clear human-computer interaction interface APK tool. MCU pass them to the BCM2073X chips, let it enter into the related testing mode.

Components Selections

For the wearable products, power consumption is the critical side for whole system. Both application requirement and power consumption should be considered during component selection. For MCU, Freescale’s KL25 is one of recommends for wearable products.

LDO or DC to DC convertor is the other key component on the board, the lower working power and the lower idle leakage current is preferred. SII S-1313 is one of recommendation with only 10nA current consumption in sleeping mode.

The other devices like G-sensor, LCD, UV-sensor, etc.Please also consider its working power consumption and standby, sleep power
consumption, make sure they have deep sleep mode and wake up mechanism, when not used, can enter into the deep sleep mode for power consumption reducing and easily return from the deep sleep mode.

Components’ dimension size is needed to be taken into the considerations, which can make the total PCB board smaller and flexible to fulfill the different shape demands of the wearable products. For example, 0201package size is preferred to the RCL parts. CSP and BGA package is recommended for IC chip,and module with more integrated functions is preferred for the ultra small wearable products.

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By Anonymous

Apr 2, 2015

1052

Smart Bluetooth

Slow reconnection

Solved

Hello,I have the following problem, I don't know if it is related to the Android-Application or the BT-Module.The first connection, when the user conn... Show More

By Anonymous

Mar 18, 2015

1473

Smart Bluetooth

Synchronization between Adv and Timers

Solved

I'd like to reduce frequency of waking-up from sleep due to battery life.When I configure 1,000[ms] as adv_interval, is advertising happens at the sam... Show More

By Anonymous

Apr 1, 2015

398

Smart Bluetooth

Lots of questions.. L2CAP/GATT/GAP, etc

Solved

Hi, According to Bluetooth SIG, the 4.1 spec for BLE supports L2CAP programming - Vendors can create profile over L2CAP. (In 4.0 spec, the custom pro... Show More

By Anonymous

Mar 30, 2015

1707

Smart Bluetooth

Notifications, Security & Bonding.

Solved

I'm trying to get a notification service up & going. The App I've got is unreliable in it's ability to successfully sign up for, & receive notificatio... Show More

I'm trying to get a notification service up & going. The App I've got is unreliable in it's ability to successfully sign up for, & receive notification data.

The code I've got so far receives a 10 byte packet from another µC every second. It then tries to push that data via a Vendor Specific Notification service created by the Smart Designer. The code doesn't request or enable security. ( /*.encr_required =*/ 0, //(SECURITY_ENABLED | SECURITY_REQUEST), // data encrypted and device sends security request on every connection)

Below is an annotated trace dump showing my App unsuccessfully signing up for notifications & then retrying resulting in success.

16:18:56 -
16:18:56 - Pckt(10):ba00 & 4a93	Packet received by Broadcom from MSP, size 10 bytes.
16:18:56 - timeout:29
16:18:57 -
16:18:57 - Pckt(10):bb00 & 4a93
16:18:57 - timeout:30
16:18:58 -
16:18:58 - Pckt(10):bc00 & 4a93
16:18:58 - timeout:31	Broadcoms 1s timer
16:18:59 -
16:18:59 - Pckt(10):bd00 & 4a93
16:18:59 - timeout:32
16:19:00 -
16:19:00 - Pckt(10):be00 & 4a93
16:19:00 - timeout:33
16:19:01 -
16:19:01 - Pckt(10):bf00 & 4a93
16:19:01 - timeout:34
16:19:02 -
16:19:02 - Pckt(10):c000 & 4a93
16:19:02 - timeout:35
16:19:03 -
16:19:03 - Pckt(10):c100 & 4a93
16:19:03 - timeout:36
16:19:04 -
16:19:04 - connection_up: 78a8735dd09b h=64	First Connection since programming.
16:19:04 Connection is UP.
16:19:04 profile idle timer stop
16:19:04 connUp
16:19:04 noAdv
16:19:04 noAdv
16:19:04 - Pckt(10):c200 & 4a93	NB: because no other messages appear here the Broadcom is not attempting to send any data because no "bonded peer" has been located.
16:19:04 - timeout:37
16:19:05 -
16:19:05 - Pckt(10):c300 & 4a93
16:19:05 - timeout:38
16:19:06 -
16:19:06 - Pckt(10):c400 & 4a93
16:19:06 - timeout:39
16:19:07 -
16:19:07 - Pckt(10):c500 & 4a93
16:19:07 - timeout:40
16:19:08 -
16:19:08 - Pckt(10):c600 & 4a93
16:19:08 - timeout:41
16:19:09 -
16:19:09 - Pckt(10):c700 & 4a93
16:19:09 - timeout:42
16:19:10 -
16:19:10 - Pckt(10):c800 & 4a93
16:19:10 - timeout:43
16:19:11 -
16:19:11 - Pckt(10):c900 & 4a93
16:19:11 - timeout:44
16:19:12 -
16:19:12 - Pckt(10):ca00 & 4a93
16:19:12 - timeout:45
16:19:13 -
16:19:13 - Pckt(10):cb00 & 4a93
16:19:13 - timeout:46
16:19:14 -
16:19:14 - Pckt(10):cc00 & 4a93
16:19:14 - timeout:47
16:19:15 -
16:19:15 - Pckt(10):cd00 & 4a93
16:19:15 - timeout:48
16:19:16 -
16:19:16 - Pckt(10):ce00 & 4a93
16:19:16 - timeout:49
16:19:17 -
16:19:17 - Pckt(10):cf00 & 4a93
16:19:17 - timeout:50
16:19:18 -
16:19:18 - Pckt(10):d000 & 4a93
16:19:18 - timeout:51
16:19:19 -
16:19:19 - Pckt(10):d100 & 4a93
16:19:19 - timeout:52
16:19:20 -
16:19:20 - Pckt(10):d200 & 4a93
16:19:20 - timeout:53
16:19:21 -
16:19:21 - Pckt(10):d300 & 4a93
16:19:21 smp timer started 00	First attempt to sign up for Notifications.
16:19:21 - timeout:54
16:19:21 -
16:19:21 SMPTmrRef
16:19:21 SMPTmrRef
16:19:22 - encryption changed 78a8735dd09b
16:19:22 SMPTmrRef
16:19:22 SMPTmrRef
16:19:22 SMPTmrRef
16:19:22 SMPTmrRef
16:19:22 SMPTmrRef
16:19:22 SMPTmrStp
16:19:22 - Pckt(10):d400 & 4a93
16:19:22 - smp_bond_result 03	Successful bonding
16:19:22 - NVRAM write:0018	Writing Bonding data to non-volatile RAM on Broadcom.
16:19:22 - timeout:55
16:19:23 -
16:19:23 - Pckt(10):d500 & 4a93
16:19:23 - don't notify handle:811	(This is the extra message that we didn't see earlier) Now the notification function has located a "bonded peer" but as far as it knows that peer hasn't signed up for notifications.
16:19:23 - don't notify handle:541
16:19:23 - timeout:56
16:19:24 -
16:19:24 - Pckt(10):d600 & 4a93
16:19:24 - don't notify handle:811
16:19:24 - don't notify handle:541
16:19:24 - timeout:57
16:19:25 -
16:19:25 - Pckt(10):d700 & 4a93
16:19:25 - don't notify handle:811
16:19:25 - don't notify handle:541
16:19:25 - timeout:58
16:19:26 -
16:19:26 - Pckt(10):d800 & 4a93
16:19:26 - don't notify handle:811
16:19:26 - don't notify handle:541
16:19:26 - timeout:59
16:19:27 -
16:19:27 - Pckt(10):d900 & 4a93
16:19:27 - don't notify handle:811
16:19:27 - don't notify handle:541
16:19:27 - write_handler: handle 0550	This is where the notifications checkbox, which is ticked from the first touch is pressed again unchecking the box, i.e. writing "0" to HDLD_ALERTS_CLIENT_CONFIGURATION (0550)
16:19:27 - handle:550 val:0000
16:19:27 - NVRAM write:0018
16:19:27 WriteCb: handle 0000
16:19:27 - timeout:60
16:19:28 -
16:19:28 - Pckt(10):da00 & 4a93
16:19:28 - don't notify handle:811
16:19:28 - don't notify handle:541
16:19:28 - timeout:61
16:19:29 -
16:19:29 - Pckt(10):db00 & 4a93
16:19:29 - don't notify handle:811
16:19:29 - don't notify handle:541
16:19:29 - timeout:62
16:19:30 -
16:19:30 - write_handler: handle 0550	2nd attempt to sign up for notifications Now the notifications checkbox on the Broadcom is pressed again, "checking" the box, writing "1"
16:19:30 - handle:550 val:0001
16:19:30 - NVRAM write:0018
16:19:30 WriteCb: handle 0000
16:19:30 - Pckt(10):dc00 & 4a93
16:19:30 - don't notify handle:811
16:19:30 - notify len:10 handle:541	Now that a bonded peer is found & that peer has signed up for notifications, data is sent reliably between connections & disconnections.
16:19:30 - timeout:63
16:19:31 -
16:19:31 - Pckt(10):dd00 & 4a93
16:19:31 - don't notify handle:811
16:19:31 - notify len:10 handle:541
16:19:31 - timeout:64
16:19:32 -
16:19:32 - Pckt(10):de00 & 4a93
16:19:32 - don't notify handle:811
16:19:32 - notify len:10 handle:541
16:19:32 - timeout:65
16:19:33 -
16:19:33 - Pckt(10):df00 & 4a93
16:19:33 - don't notify handle:811
16:19:33 - notify len:10 handle:541
16:19:33 - timeout:66
16:19:34 -
16:19:34 - Pckt(10):e000 & 4a93
16:19:34 - don't notify handle:811
16:19:34 - notify len:10 handle:541
16:19:34 - timeout:67
16:19:35 -
16:19:35 - Pckt(10):e100 & 4a93
16:19:35 - don't notify handle:811
16:19:35 - notify len:10 handle:541
16:19:35 - timeout:68
16:19:36 -
16:19:36 - Pckt(10):e200 & 4a93
16:19:36 - don't notify handle:811
16:19:36 - notify len:10 handle:541
16:19:36 - timeout:69
16:19:38 -
16:19:38 - Pckt(10):e300 & 4a93
16:19:38 - don't notify handle:811
16:19:38 - notify len:10 handle:541
16:19:38 - timeout:70

So it looks like the first attempt to sign up for notifications from the app resulted in a lesmp_sendSecurityRequest(). Is this expected behaviour when encr_required = 0?

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By Anonymous

Mar 27, 2015

657

Smart Bluetooth

Power up and down sequence for BCM20736

Solved

Hello Broadcom team,Could you please clarify the Power up and down sequence for BCM20736 device?I would like to know the detail of the timing chart li... Show More

By DaKa_1804981

Apr 1, 2015

267

Smart Bluetooth

The threshold Voltage for the Power on reset

Solved

Could you please clarify the threshold Voltage on VDDO and VDDC for the Power on reset? Show More

By DaKa_1804981

Apr 1, 2015

281

Smart Bluetooth

Host boot

Solved

Hello Broadcom team,I’m considering booting up BCM20736 from Host via SPI slave function. (Not EE-PROM or F-ROM)Can you support the Host boot like abo... Show More

By TaWa_1705256

Apr 1, 2015

423