artboffin / rocketuc Goto Github PK

Support of cap sense

Command which selects pin and "streams" data from it.
i.e. when the stream command is sent the uC replies with a stream of data, no crc or other checking.
Ends with streamEnd command

This is useful for time sensitive readings, like to read acceleration.

Create a function that when a particular even happens, such as a threshold being crossed, a flag is set.
The flag stays set until the computer side reads and clears the flag.
This is to catch fast events that may be lost in transmission latency.

In the protocol we use the term CRC, but actually we only calculate a simple checksum. This should be replaced by a real CRC. See sample C code for CRC7:

const unsigned char CRC7_POLY = 0x91;

unsigned char getCRC(unsigned char message[], unsigned char length)
{
unsigned char i, j, crc = 0;

for (i = 0; i < length; i++)
{
crc ^= message[i];
for (j = 0; j < 8; j++)
{
if (crc & 1)
crc ^= CRC7_POLY;
crc >>= 1;
}
}
return crc;
}

int main()
{
// create a message array that has one extra byte to hold the CRC:
unsigned char message[3] = {0x83, 0x01, 0x00};
message[2] = getCRC(message, 2);
// send this message to the Simple Motor Controller
}

Implement Software Reset in firmware to allow client application to call this function on exit. SW reset on MSP430 could be done by sending "wrong password" to Watchdog:

WDTCTL = 0;