The I2C topics seem to be a bit confusing.

I am creating this Blog to address these concerns.

I will post a video shortly that will thru a Code Walk Thru.

NOTE:

There is a known issue with i2cm_* functions.

You must use cfa_* functions instead.

i2cm_* can only be used when patch enable_spiff1_i2c_interop.a is used *and* NV is serial flash on SPI1

Here are miscellaneous notes that have collected regarding the I2C Issues:

Both SCL and SDA should be high before I2C communication begins.

SPIFFY1 is shared with I2C, which is already being used to talk to the EEPROM on the module.

SPI-flash and I2C interfaces concurrent:

We don’t have the drive strength once to drive the I2C line hard enough with a total of 4 slaves on the bus.

How the SDA pin is sampled during boot by the firmware and how the I2C pins behave:

• Connecting SDA to Vdd/Vio to recover is probably a bad idea
• SCL and SDA are both open-drain
• The pull-ups pull the signal high while the HW drives it low
• It never drives high, but floats the output pad leaving the pull-up to pull the line high
• If you put a scope to either of these lines on the board when the FW accesses these, high to low transitions will be very sharp while low to high transitions will be pretty slow due to the intrinsic RC
• If you connect SCL/SDA to Vdd, then when the HW block drives SDA low, there will be a direct short (though momentary) between Vdd and GND - Not good
• This will happen pretty early during boot because the ROM always uses 0xA0 as the slave address of the EEPROM and you can see that there are repeated 0s in this sequence (and the shorts) which could do bad things to the supply or the chip
• Shorting to GND on the other hand, is safer because that is what happens when there is a 0 bit on the bus and there is a 10K pull-up which will limit the current to something within the max ratings of all components on this line

How to decrease the clock speed during programming (and for subsequent accesses to the EEPROM), because the faster clock speed seems to be causing another i2c device to lock up:

See i2cm.h, i2cm_setSpeed(). Use I2CM_SPEED_* from this header.

If you use cfa_* API that is used by the i2c_temperature_sensor sample, you cannot change the I2C bus speed (defaults to 400KHz). You can use the corresponding API in i2cm.h to read/write the same data and also change speed if required

I2C and P_UART Dependency:

• PUART and I2C don't have any dependency. You can use both at the same time. SPI2 and PUART however do have some restrictions, see the datasheet or the HW interfaces document (in short - PUART RX and SI2 have to be on the same GPO bank).
• I2C and SPI1 share GPIOs. With SDK 2.1 and above, there is an optional patch with which you can use I2C when SPI1 is used for NV storage (serial flash). But the other way where you want to use SPI1 as an SPI master when using I2C EPROM slave is not possible.

To use it, you just have to include the patch and use the API in i2cm.h:

# Add to application’s makefile.mk:

APP_PATCHES_AND_LIBS += enable_spiffy1_i2c_interop.a

The in application, #include “i2cm.h”  and use the I2C API in this header to access the I2C slaves. No changes to the way you access NV (using bleprofile_*)

The cfa.h interface is where most people failed in their code

Example Code:

// Reads 16 bits from the given register address in LM73.

// \param register_address The address to the register to read.

// \param data INOUT Pointer to a INT16 into which the data is to be read, valid only if return value is 1.

// \return 1 if successful, 0 on failure.

UINT8 temperature_sensor_read_16_bit_register(UINT8 register_address, INT16* data)

{

    UINT8 read_status;

    UINT8 return_value = 0;

    UINT8 reg_read_bytes_to_write[1];

    UINT8 reg_bytes_to_read[2];

    reg_read_bytes_to_write[0] = register_address;

    // Do a combo write then read operation

    read_status = i2cm_comboRead(reg_bytes_to_read, sizeof(reg_bytes_to_read), reg_read_bytes_to_write,

                                                        sizeof(reg_read_bytes_to_write), LM73_SLAVE_ADDR);

    switch(read_status)

    {

        case I2CM_BUSY:

            // Transaction did not go through. ERROR. Handle this case.

                // There is already a pending transaction.

            break;

        case I2CM_SUCCESS:

            // The read was successful.

            *data = (INT16)(reg_bytes_to_read[1] | reg_bytes_to_read[0] << 8);

            return_value = 1;

            break;

        case I2CM_OP_FAILED:

            // No slave device with this address exists on the I2C bus. ERROR. Handle this.

        default:

            break;

    }

    return return_value;

}

// Writes the given value ino the given 16 bit register.

// \param register_address The address of the register to write to.

// \param data The data to write.

// \return 1 on success; else 0.

UINT8 temperature_sensor_write_16_bit_register(UINT8 register_address, INT16 data)

{

    UINT8 read_status;

    UINT8 return_value = 0;

    UINT8 reg_bytes_to_write[3];

    reg_bytes_to_write[0] = register_address;

    reg_bytes_to_write[1] = (data >> 😎 & 0xFF;

    reg_bytes_to_write[2] = data & 0xFF;

    read_status = i2cm_write(reg_bytes_to_write, sizeof(reg_bytes_to_write), LM73_SLAVE_ADDR);

    switch(read_status)

    {

        case I2CM_BUSY:

            // Transaction did not go through. ERROR. Handle this case.

           // There is already a pending transaction.

            break;

        case I2CM_SUCCESS:

            // The read was successful.

            return_value = 1;

            break;

        case I2CM_OP_FAILED:

            // No slave device with this address exists on the I2C bus. ERROR. Handle this.

        default:

            break;

    }

    return return_value;

}

// Reads given register by first writing the pointer register

// then reading the register value. Leaves the pointer register as is when leaving

// \param register_address The register to read from

// \param data INOUT Pointer to a buffer into which to read. Valid only if the return value is 1

// \return 1 on success; else 0.

UINT8 temperature_sensor_read_8_bit_register(UINT8 register_address, UINT8* data)

{

                UINT8 read_status;

    UINT8 return_value = 0;

    UINT8 reg_bytes_to_read[1];

    // Do a combo write then read operation

    read_status = i2cm_comboRead(reg_bytes_to_read, sizeof(reg_bytes_to_read), &register_address,

                                                        sizeof(register_address), LM73_SLAVE_ADDR);

    switch(read_status)

    {

        case I2CM_BUSY:

            // Transaction did not go through. ERROR. Handle this case.

            break;

        case I2CM_SUCCESS:

            // The read was successful.

            *data = reg_bytes_to_read[0];

            return_value = 1;

            break;

        case I2CM_OP_FAILED:

            // No slave device with this address exists on the I2C bus. ERROR. Handle this.

        default:

            break;

    }

    return return_value;

}

// Writes the given value to the given register by first writing the pointer register

// then writing the value. Leaves the pointer register as is when leaving.

// \param register_address The address of the register to write to.

// \param data The data to write to the register.

// \return 1 on success; else 0.

UINT8 temperature_sensor_write_8_bit_register(UINT8 register_address, UINT8 data)

{

    UINT8 read_status;

    UINT8 return_value = 0;

    UINT8 reg_data_bytes[2];

    reg_data_bytes[0]= register_address;

    reg_data_bytes[1] = data;

    read_status = i2cm_write(reg_data_bytes, sizeof(reg_data_bytes), LM73_SLAVE_ADDR);

    switch(read_status)

    {

        case I2CM_BUSY:

            // Transaction did not go through. ERROR. Handle this case.

            break;

        case I2CM_SUCCESS:

            // The read was successful.

            return_value = 1;

            break;

        case I2CM_OP_FAILED:

            // No slave device with this address exists on the I2C bus. ERROR. Handle this.

        default:

            break;

    }

    return return_value;

}

                                   

• Code Overview
  
  • iBeacon and SDK 2.1 Code Overview
  • WICED Smart BCM2073X Coding Tips from user maxsong...
  • WICED Smart Training videos, compliments of Macnica North America...
  • BCM92073X BLE Profile Configuration

• General Questions
  
  • BCM20732 questions
  • How to get started (coming from arduino)
  • What is difference between being connected versus paired?
  • Wiced Smart Software Runtime -- Lots of Questions
  • About BCM20737S
  • BCM20737s: NFC Reader or only TAG?

• Hardware Design between 2073X and External MCU

• Reference Design/Schematics
  
  • New iBeacon BCM20737 Reference Design
  • Experts Interview Video: Michael L. - IBCN BCM20737 Schematic Review
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• Layout
  
  • BCM20732 layout options
  • BCM20737S input capacitors and placement
  • BCM20732S layout
  • Are pullup resistors always needed on 20732 SCL and SCA pins?
  • Exact Location of internal PIFA Antenna on BCM20737S
  • 20732S XTAL (32KHz)

• General
  
  • WICED Smart Video BLOG: SDK 2.1 Smart Designer Tool Walk-Thru
  • WICED Smart BCM92073X GATT DB Operation
  • Lots of questions.. L2CAP/GATT/GAP, etc
  • Multiple Notifications in an App...?
  • Support for very large characteristics

• Other
  • How to change the GATT database after init (bleapp_set_cfg) ?
  • Is pairing/encryption mandatory to allow a peer to write in GATT

• Advertising
  
  • Customizing Advertising on WICED Smart
  • Best way to rewrite advertisement data
  • Connectable vs. nonconnectable Advertisements.
  • How to change advertisement interval after init?
  • Advertising during connection
  • bleprofile_notifyAdvPacketTransmissions doesn't work.

• Callback to modify single advertisments?
• About the bleprofile_GenerateScanRspData function?
• How to register callback for ADV events ?

• Scanning
  
  • Scan sometimes stops working
  • Scheduling of scan window and connection window

• Additional master/slave questions on BCM20736/7 family
• Re: How best to implement bulk data transport
• smp_bond_result 04
• Connection Event Callback API
• Connection Event Callback API (follow-on)
• Connection Interval and Connection Slave Latency
• When does bleprofile_sendNotification() actually send?
• Check if bleprofile_sendNotification() was successful
• Slow reconnection
• Sometimes connection not bonding

• Adding and removing master nodes to a whitelist running on a peripheral device

• General
  
  • BCM2073XS GPIO Basics
  • Can someone tutor me on GPIO usage?
  • GPIO Headers
  • BCM20732S PIN information
  • BCM2073xS (BCM20737S) GPIO bonding

• Interrupts
  • Access_tag_interrupt_handler
  • How to identify GPIO interrupt source pin?
  • Buttons in hello_sensor.c
  • How can I wake BCM20737S up by using GPIO interrupt?
  • How to disable interrupt?
  • GPIO in high impedance mode
  • Wake up on GPIO interrupt

• General
  
  • Information: Debug the BCM20732 Tag over HCI-UART using a COM port via USB on the PC
  • How to debug the board step by step?
  • Information: BCM20732S debug/trace capabilities through the HCI UART port
  • How do I interpret the extra tracing data ?
  • Testing Master and Slave Roles
  • How can I use ble_trace() for application debug?
  • How to get debug traces ?
  • WICED Sense debug with UART
  • How to disable 20737S SDK trace, BLE_TRACE_DISABLE?

• J-Link
  • WICED Smart J-Link Debugger
  • WICED Smart - Debugging Support Using a J-Link Probe Application Note

• BCM92073X TAG Power Supply Configurations
• Power level granularity in blecm_setTxPowerInConnection() and blecm_setTxPowerInADV()
• Current Draw and Advertising Timing on the WICED Sense (BCM20737S)
• how to reduce the power consumption when use puart ?
• BCM20737S Current Consumption Voltage Condition and more...
• [BC20636S] Power consumption advantages when using external oscillator

• BLE RF Testing Specification Introduction
• BLE RF Testing Setup Procedures

• General
  
  • WICED Smart Video BLOG: Experts Interview - Sleep Deep_Sleep and Advertising
  • Sleep Deep_Sleep Explanation and Techniques
  • WICED Smart Sleep/Deep-Sleep Explanation and Techniques Design Guide
  • BCM20736S Sleep Example Firmware
  • Questions sleep and deep sleep modes on BCM20737
  • GPIO Interrupt State after Deep Sleep

• Entering Sleep
  
  • How to enter HIDOFF?  How to detect if the request is not honored?
  • Putting '20732S into sleep or deep sleep mode
  • BCM20736S HIDOFF problem
  • Problem with sleep mode
  • Sleep Mode on 20736S

• Waking From Sleep
  • Boot Time of WICED Smart Tag Board (BCM20737)
  • GPIO state in deep sleep
  • For wake on GPIO interrupts, please look under GPIO->Interrupt
    

• WICED™ Smart Hardware Interfaces
• BCM20736S I2C, PUART and SPI comms
• SPI1 access or send command to flash in application level.

• Memory:
  • BCM20732 Memory Map Architecture
  • BCM92073X TAG Memory and Programming Configurations
  • WICED Smart BCM92073X I2C EEPROM Emulation Porting Guide
  • WICED Smart BCM92073X EEPROM and SFLASH Layout
  • WICED Smart BCM92073X NVRAM Access
  • Memory size limits on 20732?
  • BCM20732S NVRAM Size
  • nvram: number of locations to write to
  • BCM20736S I2C, PUART and SPI comms
  • It seems that I can not read the data is stored in NVRAM before the last power off.
  • Layout of VS1 in the EEPROM
  • Re: Accessing the 512 kb (64 kB) EEPROM in the 20737S module

• PWM:
  • LED with PWM
  • Different Frequencies for PWM
  • How many PWM channels available in BCM20732S ?
  • BCM92073x periodic interrupt rate
  • How to turn on LED

• ADC:
  • BCM20732S ADC Configuration
  • Questions related to the ADC implementation on the BCM2073XS...
  • ADC on BCM20732

• UART:
  • Information: Programming your BCM20732S-based board from an onboard UART header
  • UART does not receive
  • UART Routines
  • BCM20732S based boards sometimes develop UART failure
  • Spec for uploading firmware to the BCM20732S via HCI UART?
  • puart_write() crashing on BCM20736?
  • Peripheral UART missing bytes
  • Problem with UART watermarks
  • PUART RTS/CTS Hardware Flow Control
  • What are the PUART FIFO Rx interrupt threshold settings?
  • Need clarification on PUART RTS/CTS flow control support

• I2C:
  • I2C Discussion
  • BCM20736S recovery problem - SDA high does not enter recovery mode
  • How can I use i2c in BCM20737S?

• SPI:
  • SPI on BCM920732TAG
  • Spi Debug
  • SPI flow control

• Timer in 2073x
• BCM20737S Timer Module

• Software/Usage
  
  • appFineTimer
  • FineTimer
  • What is the best way to set an application timer to fire?
  • how to config RTC use external 32.768?
  • Re: How to use real time tick clock?
  • rtc_sample bricks our BCM20736S-based board
  • Turning off the timers in BCM20736S
  • Hello_client/blecen Timer Callback Questions

• Watchdog Timer
  • How can I get bcm20732s reset reason?
  • Increasing/Disabling the watchdog timer

• Crystal
  • Explanation of Crystal Warmup Issue
  • Crystal warm-up work-around video...
  • 32kHz Crystal Spec?
  • Internal vs. External Oscillator

• RTC
  • rtc_RtcTime2Sec() returns wrong seconds when RtcTime.year is 2016
  • How to use real time tick clock?
  • rtc_sample bricks our BCM20736S-based board
  • how to config RTC use external 32.768?

• Watchdog Timer
  • Increasing/Disabling the watchdog timer
  • How can I get bcm20732s reset reason?

• Hardware Timer
  • How to use 100us interval timer?
  • Hardware Timer (hw_timer.h) usage
  • HW Timer in 2073x
  • Timer in 2073x
  • Wiced Sense hardware timer example
  • Wiced Sense hardware timer example (part 2)

• WICED Smart BCM92073X OTA Firmware Upgrade (1)
• WICED Smart BCM92073X OTA Firmware Upgrade (2)
• How to do OTA: Step by Step with PDF
• SOTAFU for Android and iOS
• Why error occur when I open WsOtaUpgrade.exe?
• Why error occur when I open WsOtaUpgrade.exe? (continued)
• Issue with using Windows OTA upgrade app

• How to recover BCM20736S on custom board?

Security:

• Encryption API
• How to operate RSA in BCM20737S & BCM20737S document
• Update on RSA and/or app note for BCM20737?
• BCM20736S and RSA
• RSA Document
• BCM20737S: LE security mode1 level3/4 supported?

• Programming manufacturing data during production
• Do I need to register separately with the Bluetooth SIG to use the Bluetooth logo in my product?

• BD_ADDR - how do you get one?
• BD_ADDR: Changing BCM20737 Board Address for Production
• Changing BD_ADDR from the application
• Video Link : 1216

• Programming the TAG2/TAG3 Board using command line tools
• BCM20732S refuses to program
• cgs.exe and ChipLoad.exe

• WICED Smart BCM92073X Generate Your Own UUID

• Broadcom BCM20732S/BCM20736S/BCM20737S Regulatory Approvals
• Certification from Bluetooth SIG
• 20732S regulatory certification
• More questions regarding FCC certification on the BCM2073XS Product
• FCC Certification Flow for Broadcom module products
• FCC approval for BCM20736S