panStamp NRG. Technical details
- Introduction
- Specifications
- Pin mapping
- Memory Organization
- Info memory
- Programming methods
- Memory Organization
- Serial programming. Booting sequence
- Files
NRG modules share the same footprint and similar pinout as the AVR model but use a MCP430 core instead of an Atmega MCU. Optionally, panStamp can include an on-board 3-axis accelerometer and a temperature-humidity sensor.
- Dimmensions: 0.7 x 1.2 in (17.7 x 30.5 mm)
- MCU: CC430F5137 (MSP430 core + CC11XX radio SOC)
- Speed: Programmable speed between 8MHz and 24MHz
- Flash: 32KB
- RAM: 4KB
- Info memory: 512 bytes
- Unique MAC address
- Voltage range: from 2VDC to 3.6VDC
- Rx current: 18 mA max
- Tx current: 36 mA max
- Sleep current: 1-2 uA
- Maximum Tx power: +12 dBm
- RF bands: 868/905/915/918 MHz ISM bands
- Communication length: 200m in open spaces at 0dBm with pigtail antenna
- 128-bit AES Security Encryption
- (Optional) MMA8652FFC 3-axis accelerometer on the top layer
- (Optional) SI7021 dual temperature – humidity sensor on the bottom layer
- (Optional) Thermistor on the bottom layer
- On-board LED
- Footprint for SMA edge connector
- Programmable via SBW, serial GDB and wirelessly (SWAP)
One of the great things about the CC430 processor is that digital functions (green lines) can be moved to any P1 or P2 pin. Green text shows the default position of these functions.
The following table shows how the memory of the CC430F5137 MCU is distributed:
One of the interesting things about the MSP430 architecture is that Flash and RAM share a common addressing schema so that we can access address locations in the same way, regardless of the nature of the memory. This is really appreciated for example when a given constant variable needs to be permanently located in flash since this variable will never be copied into RAM by the stack.
CC430 processors do not include EEPROM space. Instead, they provide a special region in Flash to store configurations. This region is called info memory and is 512 bytes long in the CC430F5137 MCU. The panStamp library provides the necessary functions to use this info space as any other EEPROM-based region.
panStamp NRG can be programmed in three different ways. The first method is SBW (Serial bi-wire) JTAG interface. Any MSP430 programmer supporting SBW can be used to program panStamps, including MSP430 Launchpads and ez430 programmers, which are very low cost programming interfaces.
On the other hand, panStamp NRG can also be programmed serially from GDB, the popular open source debugging software. Any kind of USB-UART converter can be used for this task. Serial programming is the method used when loading firmware images from the Arduino 1.5 IDE.
The following is the necessary wiring diagram according of the programming method being used:
Finally, panStamp NRG can be flashed (following one of the above methods) with SWAP firmware loader. With this bootloader in place, NRG modules can be wirelessly programmed from SWAPdmt (command-line version).
panStamp's serial firmware loader, developed by Rick Kimball, is a compact implementation of the GDB server for the CC430 familly. Although this server doesn't provide full debugging capabilities, it can be used to read and write memory sections without having to load any specific firmware into the target board. This GDB bootloader replaces the old BSL loader flashed by Texas Instruments in their chips. Unlike Atmega's, CC430 processors include a separate 2KB region in flash called "BSL memory" that can be used to store bootloaders. Thus, programmers can still keep the whole 32KB flash region for their programs.
In order to load a new firmware, the panStamp NRG board has to enter the bootloading mode. This is achieved by connecting P2.0 to ground before rebooting the board. Once the board has been programmed and in order to exit from bootloading mode, P2.0 has to be unconnected from ground and then a new reset or power-cycle has to be applied to the board.
Like the AVR version of panStamp, most of the critical aspects of the NRG board (radio, power management, RTC, ...) are covered by the panStamp library and core functions and only generic functions like UART, SPI, I2C and I/O management are delegated to Arduino in order to guarantee compatibility with other libraries.
Schematics (pdf)