Specifications

Device Drivers

The device drivers represent most of the device speciﬁc code in the ﬁrmware. Supp ort

for all hardware features are found here. The only requirement for this module is that the

feature functions correctly with as little resource use as possible. Below is the list of drivers

that must be elaborated on:

1. Serial Communications- Driver must contain handlers for transmitting and r eceiv-

ing using one of the MCU’s UARTs. Drivers must support low-overhead interrupts

to accomplish full-duplex d ata transfers. This driver is allowed one static buﬀer to

store received data. The drivers are responsible for encapsulating messages with cyclic

redundancy checks (CRC) for error detection.

2. ZigBee Communications- This driver must handle the low-level UART communi-

cations supported by the MCU. I t mus t also format and interpret any messages to be

used by a ZigBee radio. Other support for radio commands and radio updates must

also be d eﬁ ned.

3. Removable Flash Memory Disk Controller- This driver must contain all the

necessary disk I/O functionality so that the ﬁle system layer can access the d isk. This

may include functions to activate, deactivate, read, write, erase, and format the disk.

4. SDI-12 Communications- Driver must support message passing compliant to the

SDI-12 V1.3 speciﬁcation.

5. Analog Measurement- This driver mu s t operate all hardware n ecessary to convert

analog signals to digital values.

6. Digital Measurement- This driver must operate all hardware necessary to charac-

terize digital signals. This may include timer and capture/compare hardware manip-

ulation.