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Formal Tag4 Documentation:

Hardware User Guide (SDK 2.x and TAG4 Board)

WICED Smart Quick Start Guide (SDK 2.x and TAG4 Board)




Tag 4 Quick Hardware Setup:


       1. Default switch settings for USB power, Booting SFLASH:

                 A. SW6 – 2,4 ON, rest OFF

                 B. SW9 – all ON

                 C. SW8 – 2, 3, 6, 7, 8 ON, rest OFF

                 D. SW4 - VUSBs

                 E. SW5 – VREG

       2. On it's very first download, the board requires a recovery:

                 A. Press-hold BOOT, press-release RESET, release BOOT

                 B. Edit any make target: replace “download” with “recover UART=COMxx”

                 C. Use make target. Replace ‘xx’ with your COM port (found in Device Manager)

                 D. Double click make target to execute build.

       NOTE: After your initial recovery, regular “download” can be used.


Tag 4 Traces:


       1. Start traces:

                 A. Download your app

                 B. Switch SW6 1,2,3 OFF, 4 ON

                 C. Enable traces on the SDK (WICED Smart IDE > Trace > Start Debug Traces)

                 D. Press reset button

       2. Stop traces:

                 A. Disable traces on the SDK (WICED Smart IDE > Trace > Stop Debug Traces)

                 B. Switch SW6 1, 3 OFF, 2, 4 ON

                 C. Power cycle the Tag 4 board

       NOTE: if the board is not power cycled after stopping traces it will not download

       NOTE: the SDK traces must be stopped before they will start again.


Tag 4 Power Measurements:


       1. Basic Power measurement

                 A. Remove R29

                 B. Attach power analyzer to J12

                 C. Run an app, and start analysis

                 NOTE: Leads of J12 must be shorted by power analyzer in order to download app

       2. Power Optimization:

                 A. 20737 Chip Specific Optimization:

                      - Move RD5 and RD6 to A-C position (switches to external DC-DC converter)

                 B. To reduce peak current of RF TX:

                     - Remove FB3, disabling FTDI chip (download your app first)

                 C. To reduce idle current of board:

                      - Remove R39: disables I2C Expander (no sensors will function)


Tag 4 Boot Sources:

       1. Boot EEPROM

                  A. SW8 – 1,3,5 ON, rest OFF

                  B. Power cycle

       2. Boot SFLASH

                  A. SW8 – 2,3,6,7,8 ON, rest OFF

                  B. Power cycle

       3. Boot ROM only

                  A. Press and hold the 'ROM' button on the board

                  B. Power cycle

                  C. Release 'ROM' button

NOTE: when switching between boot sources it is often necessary to perform a recovery


Tag 4 I2C:


       1. Without any additional action, I2C APIs will only interact with EEPROM.

       2. In order to interact with the on-board MEMS sensors and bring out I2C onto J10:

                  A. The on-board I2C expander must be output enabled by calling:


 gpio_configurePin((GPIO_PIN_P8) / 16, (GPIO_PIN_P8) % 16, GPIO_OUTPUT_ENABLE, 1);


                  B. The I2C voltage rail must be powered by calling:


 gpio_configurePin((GPIO_PIN_P2) / 16, (GPIO_PIN_P2) % 16, GPIO_OUTPUT_ENABLE, 0);



Jacob W Torres


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