BM70 Compact Demo Board User's Guide: Chapter 2. Interface Description

Last modified by Microchip on 2023/11/10 11:11

2.1 Introduction

This chapter provides details on the components and the interface for the following boards:

  • BM-70-CDB
  • Sensor Board

2.2 BM-70-CDB

The accompanying image shows the components of the BM-70-CDB. The labels on the components correspond with the interface description list in section 2.2.1.

The CDB can be used in stand-alone mode powered by either an external USB or a coin cell battery.

BM-70-CDB Module

Figure 2-1: BM-70-CDB

2.2.1 Interface Description

  1. BM70 module
  2. Status indicator LED (LD2); for blink rate descriptions, refer to the “BM70/71 Bluetooth® Low Energy Module Data Sheet” (DS60001372)
  3. Push button for hardware Reset (SW1)
  4. Current measurement test point (J8)
  5. Header pins for coin cell battery connection (J6, close pins 1 and 2)
  6. Header pins for USB power (J6, close pins 3 and 2)
  7. MCP2200 - USB to UART bridge
  8. Micro USB connector
  9. DIP switches (SW2)
    • Switch 1 and 4 on SW2 can be used as user-programmable switches.
    • Status switch (Switch 3 on SW2) enables/disables status LED (LD2)
    • Mode switch (Switch 2 on SW2) selects the mode of operation (programming/application)
  10. CN1, CN2 and CN3 are header pins to the BM70 module pins. The header pins can be used to connect to the Sensor Board or as test points.

While updating the firmware on the BM-70-CDB, the J6 jumper pins 2 and 3 should be closed and jumper J8 (current measurement test point) should be closed. The jumpers J6 and J8 should not be disturbed during firmware updates, otherwise, the firmware could be corrupted.

2.3 Sensor Board

The Sensor Board is an accessory designed for the BM-70-CDB to demonstrate the peripheral I/O capabilities of the BM70. Figure 2-2  shows the Sensor Board with its main components indicated by numbered labels. The labels correspond with the interface description list in section 2.3.1.

The Sensor Board is used with the BM-70-CDB to demonstrate digital and analog I/O capabilities over Bluetooth Low-Energy connections. To use the Sensor Board with the BM-70-CDB, it must be configured as described in Chapter 5. “RN4870 Sensor Board".

BM-70-CDB Sensor Board

Figure 2-2: RN4870 Sensor Board

2.3.1 Interface Descriptions

  1. Test Point for ADC channels of the BM70 module
  2. Variable Resistor to drive ADC0 input
  3. DIP Switch block to connect or disconnect sensors from the BM70 module
  4. LED connected to pin P22
  5. Light Sensor connected to ADC1 input
  6. Push the Button connected to PIO2

All the switches on DIP switch block SW2 should be in the ON position before running the demos in this document.

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