/**
@defgroup boards_msb430 MSB-430
@ingroup boards
@brief Support for the ScatterWeb Modular Sensor Board 430
## MCU
| MCU | TI MSP430F1612 |
|:----------------- |:------------------------------------------------------------- |
| Family | MSP430 |
| Vendor | Texas Instruments |
| Package | 64 QFN |
| RAM | 5 KiB |
| Flash | 55 KiB |
| Frequency | up to 8 MHz |
| FPU | no |
| Timers | 2 (2x 16bit) |
| ADCs | 1x 8 channel 12-bit |
| UARTs | 2 (*) |
| SPIs | 2 (*) |
| I2Cs | 1 (*) |
| Vcc | 1.8 V - 3.6 V (battery holder board provides 3.0 V) |
| Datasheet MCU | [Datasheet](https://www.ti.com/lit/ds/symlink/msp430f1612.pdf)|
| User Guide MCU | [User Guide](https://www.ti.com/lit/ug/slau049f/slau049f.pdf) |
| Website | [MSB-430](https://www.mi.fu-berlin.de/inf/groups/ag-tech/projects/ScatterWeb/modules/mod_MSB-430.html) |
@warning While programming, the minimum supply voltage is 2.7 V instead of
1.8 V.
@warning When the supply voltage supervisor (SVS) (a.k.a. brownout detection)
is used, the supply voltage must initially be at least 2.0 V due to
the hysteresis of the SVS circuitry. Afterwards the MCU remains
operational with VCC >= 1.8 V.
@warning The MSP430F1612 has two USARTS, which can be configured as UART,
SPI, or (only in case of USART0) as I2C bus. Each USART can only
provide one serial interface at a time; time sharing is
theoretically possible but not yet implemented.
## Schematics
### Hardware Limitations
The GPIOs on the MSP430F1612 only have two MUX settings: Being used as digital
input/output or routed to a peripheral. The MCU has two universal serial
synchronous/asynchronous communication interfaces (USARTs), which can be
used to provide either an UART, an SPI, or (only in case of USART0) an I2C bus.
Every USART signal is available at exactly one GPIO pin.
The UART exposed via the battery holder board (P3.6 and P3.7) can only be
provided via USART1. In order to support asynchronous reception (e.g. to allow
interaction via the shell), USART1 needs to be continuously configured as UART
and cannot be used to provide an SPI bus.
The SPI bus connected to the SD card socket (P5.1, P5.2, and P5.3) can only
be provided via USART1. Hence, it is not possible to use SPI bus connected to
the SD card socket while the UART used for `stdio` is in use, as they use the
same USART. They could be used at the same time, if module `stdin` is not used
(the UART is output only). However, sharing USARTs is not yet implemented.
The SPI bus of the CC1020 transceiver (used for configuration only) is connected
to pins P2.0, P2.1, and P2.3. Those pins are not connected to either USART, so
no hardware SPI can be used to interact with the transceiver. However, the SPI
is only used for configuration and control of the transceiver, so using a slow
bit-banging SPI bus won't affect the performance of the transceiver, other than
for quick power down after transmission or channel hopping. A second two
wire serial interface (not I2C or compatible) is used to feed data into
the CC1020 or read data from the CC1020. The serial clock is driven by the
transceiver and the MCU needs to keep up with providing the frames to send
bit by bit. Unlike modern transceivers, the CC1020 has no frame buffer and the
MCU needs to control the transmission and reception on the bit level.
## Pinout
### Pinout of the Main MSB 430 Board
### Pinout of the Battery Holder Board
The pins above the JTAG header with the pin closest to the power supply switch
being denoted as Pin 1, the signals are as follows:
| Pin | 1 | 2 | 3 | 4 | 5 | 6 |
|:--------- | -----:| -----:| -----:| -----:| -----:| -----:|
| Signal | GND | NC | 5V | RXD | TXD | NC |
The battery holder board contains a 3V power regular that powers the MSB-430
board via 3V pin (pin 1 on JP2). The switch at the bottom can be used to select
the input voltage of that power regulator: If the switch is in the position
towards the daughter board, it will use the 5V pin of the header above the
JTAG header as power supply, otherwise the batteries are used as power supply.
## Flashing RIOT
Place the MSB-430 board into the batter holder board with the SD card socket
facing towards the battery holder board and the (likely unpopulated) antenna
connector facing away from the switch and JTAG-connector of the battery holder
board. (As shown in the picture at the top of the page.)
Afterwards, connect a JTAG debugger supported by
[mspdebug](https://dlbeer.co.nz/mspdebug/); by default the
Olimex MSP430-JTAG-Tiny is assumed, which is among the less expensive options.
@note If you are not using the Olimex MSP430-JTAG-Tiny (or a compatible
programmer), set `MSPDEBUG_PROGRAMMER` to the correct value via
an environment variable or as parameter to make. E.g. use
`make BOARD=msb-430 MSPDEBUG_PROGRAMMER=bus-pirate` to
flash using the bus pirate.
@warning It is recommended to use the external power supply via the 5V pin
instead of the battery while flashing.
Once the board is firmly connected in the battery holder and the JTAG cable is
connected, just run
```
make BOARD=msb-430 flash
```
in the application's directory.
## Using the shell
stdio is available via the UART interface with `RXD = P3.7`
(pin 35 on the header) and `TXD = P3.6` (pin 34 on the header) at 115,200 Baud.
The easiest way is to connect an USB TTL adapter (such as the cheap `cp210x`
or `ch341` based adapters) to the battery holder board as follows:
```
TTL adapter MSB-430 Battery Holder Board
----------- ----------------------------
GND --- 1 (GND)
TXD --- 4 (RXD / P3.7)
RXD --- 5 (TXD / P3.6)
5V --- 3 (5V)
```
*/