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implement RcxSend;
include "sys.m";
include "timers.m";
include "rcxsend.m";
sys : Sys;
timers : Timers;
Timer : import timers;
datain : chan of array of byte;
debug : int;
rpid : int;
wrfd : ref Sys->FD;
TX_HDR : con 3;
TX_CKSM : con 2;
init(portnum, dbg : int) : string
{
debug = dbg;
sys = load Sys Sys->PATH;
timers = load Timers Timers->PATH; #"timers.dis";
if (timers == nil)
return sys->sprint("cannot load timer module: %r");
rdfd : ref Sys->FD;
err : string;
(rdfd, wrfd, err) = serialport(portnum);
if (err != nil)
return err;
timers->init(50);
pidc := chan of int;
datain = chan of array of byte;
spawn reader(pidc, rdfd, datain);
rpid = <- pidc;
consume();
return nil;
}
reader(pidc : chan of int, fd : ref Sys->FD, out : chan of array of byte)
{
pidc <- = sys->pctl(0, nil);
# with buf size of 1 there is no need
# for overrun code in nbread()
buf := array [1] of byte;
for (;;) {
n := sys->read(fd, buf, len buf);
if (n <= 0)
break;
data := array [n] of byte;
data[0:] = buf[0:n];
out <- = data;
}
if (debug)
sys->print("Reader error\n");
}
send(data : array of byte, n, rlen: int) : array of byte
{
# 16r55 16rff 16r00 (d[i] ~d[i])*n cksum ~cksum
obuf := array [TX_HDR + (2*n ) + TX_CKSM] of byte;
olen := 0;
obuf[olen++] = byte 16r55;
obuf[olen++] = byte 16rff;
obuf[olen++] = byte 16r00;
cksum := 0;
for (i := 0; i < n; i++) {
obuf[olen++] = data[i];
obuf[olen++] = ~data[i];
cksum += int data[i];
}
obuf[olen++] = byte (cksum & 16rff);
obuf[olen++] = byte (~cksum & 16rff);
needr := rlen;
if (rlen > 0)
needr = TX_HDR + (2 * rlen) + TX_CKSM;
for (try := 0; try < 5; try++) {
ok := 1;
err := "";
reply : array of byte;
step := 8;
for (i = 0; ok && i < olen; i += step) {
if (i + step > olen)
step = olen -i;
if (sys->write(wrfd, obuf[i:i+step], step) != step) {
if (debug)
sys->print("serial tx error: %r\n");
return nil;
}
# get the echo
reply = nbread(200, step);
if (reply == nil || len reply != step) {
err = "short echo";
ok = 0;
}
# check the echo
for (ei := 0; ok && ei < step; ei++) {
if (reply[ei] != obuf[i+ei]) {
err = "bad echo";
ok = 0;
}
}
}
# get the reply
if (ok) {
if (needr == 0)
return nil;
if (needr == -1) {
# just get what we can
needr = TX_HDR + TX_CKSM;
reply = nbread(300, 1024);
} else {
reply = nbread(200, needr);
}
if (len reply < needr) {
err = "short reply";
ok = 0;
}
}
# check the reply
if (ok && reply[0] == byte 16r55 && reply[1] == byte 16rff && reply[2] == byte 0) {
cksum := int reply[len reply -TX_CKSM];
val := reply[TX_HDR:len reply -TX_CKSM];
r := array [len val / 2] of byte;
sum := 0;
for (i = 0; i < len r; i++) {
r[i] = val[i*2];
sum += int r[i];
}
if (cksum == (sum & 16rff)) {
return r;
}
ok = 0;
err = "bad cksum";
} else if (ok) {
ok = 0;
err = "reply header error";
}
if (debug && ok == 0 && err != nil) {
sys->print("try %d %s: ", try, err);
hexdump(reply);
}
consume();
}
return nil;
}
overrun : array of byte;
nbread(ms, n : int) : array of byte
{
ret := array[n] of byte;
tot := 0;
if (overrun != nil) {
if (n < len overrun) {
ret[0:] = overrun[0:n];
overrun = overrun[n:];
return ret;
}
ret[0:] = overrun;
tot += len overrun;
overrun = nil;
}
tmr := timers->new(ms, 0);
loop:
while (tot < n) {
tmr.reset();
alt {
data := <- datain =>
dlen := len data;
if (dlen > n - tot) {
dlen = n - tot;
overrun = data[dlen:];
}
ret[tot:] = data[0:dlen];
tot += dlen;
<- tmr.tick =>
# reply timeout;
break loop;
}
}
tmr.destroy();
if (tot == 0)
return nil;
return ret[0:tot];
}
consume()
{
while (nbread(300, 1024) != nil)
;
}
serialport(port : int) : (ref Sys->FD, ref Sys->FD, string)
{
serport := "/dev/eia" + string port;
serctl := serport + "ctl";
rfd := sys->open(serport, Sys->OREAD);
if (rfd == nil)
return (nil, nil, sys->sprint("cannot read %s: %r", serport));
wfd := sys->open(serport, Sys->OWRITE);
if (wfd == nil)
return (nil, nil, sys->sprint("cannot write %s: %r", serport));
ctlfd := sys->open(serctl, Sys->OWRITE);
if (ctlfd == nil)
return (nil, nil, sys->sprint("cannot open %s: %r", serctl));
config := array [] of {
"b2400",
"l8",
"po",
"m0",
"s1",
"d1",
"r1",
};
for (i := 0; i < len config; i++) {
cmd := array of byte config[i];
if (sys->write(ctlfd, cmd, len cmd) <= 0)
return (nil, nil, sys->sprint("serial config (%s): %r", config[i]));
}
return (rfd, wfd, nil);
}
hexdump(data : array of byte)
{
for (i := 0; i < len data; i++)
sys->print("%.2x ", int data[i]);
sys->print("\n");
}
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