AMTI MSR-6 interface

init.ls

#!/usr/bin/env lsc
require! {
  'serialport': {SerialPort}
}
say = console.~log
timeout = (t, f) -> setTimeout(f, t)
PORT = 'COM3'

s = new SerialPort PORT, baudrate: 57600

err <- s.on 'open'
if err then throw err
say 'opened at 57600'

err <- s.write Buffer [0x52 0x53]
if err then throw err
say 'wrote 0x52 0x53 (stop, autozero)'
say 'idle wait for autozero'
<- timeout 1250
say 'done'

err <- s.write Buffer [0x76]
if err then throw err
say 'wrote 0x76 (very high speed output)'

err <- s.close
if err then throw err
say 'closed 57600'

s = new SerialPort PORT, baudrate: 115200

err <- s.on 'open'
if err then throw err
say 'opened at 115200'

err <- s.write Buffer [0x51]
if err then throw err
say 'wrote 0x51 (start streaming)'

err <- s.close
if err then throw err
say 'closed 115200'

say 'success'

read.c

/* ... */

/*
 * const int N = 6; // total number of channels
 * const int K = 3; // lookahead window size (in readings)
 * const int KK = 2*K; // ditto (in bytes)
 * uint16_t* rptr; // points to read index of circular buffer
 * uint16_t* wptr; // points to write index of circular buffer
 * uint16_t fifosize; // size of circular buffer
 * uint16_t fifocount = (*wptr - *rptr) % fifosize; // number of items currently in circular buffer
 * int* data; // content of circular buffer
 * uint16_t DPtr[N]; // output vector (decoded data)
 */

    found = 0;
    for (i = 0 ; i + KK <= fifocount ; ++i, ++*rptr) {
        found = 1;
        for (j = 1 ; j < KK ; j += 2) {
            uint8_T ch = ((uint8_T)data[(*rptr + j)%fifosize] & 0xF0) >> 4;
            if (!(0 <= ch && ch < N)) {
                found = 0;
                break;
            }
        }
        if (found) break;
    }
    if (!found) return;
    for (j = 0 ; j < KK ; j += 2) {
        uint8_T b0 = data[(*rptr + j)    %fifosize];
        uint8_T b1 = data[(*rptr + j + 1)%fifosize];
        unsigned short val = b0 | ((b1 & 0x0F) << 8);
        unsigned short ch = (b1 & 0xF0) >> 4;
        DPtr[ch] = val;
    }
    *rptr = (*rptr + KK)%fifosize;

/* ... */