/*
This file is part of JOP, the Java Optimized Processor
see <http://www.jopdesign.com/>
Copyright (C) 2001-2008, Martin Schoeberl (martin@jopdesign.com)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package jembench.kfl;
/**
* message handling.
* Mast and Zentrale.
*/
public class Msg {
static final int IO_STATUS = 1;
static final int IO_UART = 2;
static final int IO_RS485 = 15;
//
// comm timeout for Zentrale
// must include send and receive time (2*1 ms)
// minimum 2*INTERVAL + 2ms (=> >12ms)
//
// msg time: 1/38400*10*4 + 100us = 1.14 ms
//
// measured: 12 ms is ok
// but max. msg turnaround with bus idle is 18-19 ms
// so 15 ms is a good value
//
private static final int COMM_TIMEOUT = 15*JopSys.MS;
private static final int EXT_COMM_TIMEOUT = 100*JopSys.MS; // for msg FL_PROG!
private static final int ADDR_MSK = 0x7c0000;
private static final int CMD_MSK = 0x03f000;
private static final int DATA_MSK = 0x000fff;
private static int address;
//
// buffer for serial and rs485 input
//
private static int[] buf, bufSer, buf485;
private static int cntSer, cnt485;
private static boolean send; // send a msg in loop (is in buf)
private static int cmd;
private static int val;
/** one message pending. */
public static boolean available;
public static boolean msg485; // msg. from rs485 (or rs232)
/**
* initailize buffers and set station address.
*/
public static void init(int addr) { // it would be time to change jvm for objects!!!
address = addr<<18;
bufSer = new int[4];
buf485 = new int[4];
buf = new int[4];
cntSer = cnt485 = 0;
available = false;
send = false;
}
/*
* set new address
*/
public static void setAddr(int addr) {
address = addr<<18;
}
/*
better values for polynom on short messages see:
'Determining optimal cyclic codes for embedded networks'
(www.cmu.edu)
*/
/**
* claculate crc value with polynom x^8 + x^2 + x + 1
* and initial value 0xff
* on 32 bit data
*/
static int crc(int val) {
int reg = -1;
for (int i=0; i<32; ++i) { // @WCA loop=32
reg <<= 1;
if (val<0) reg |= 1;
val <<=1;
if ((reg & 0x100) != 0) reg ^= 0x07;
}
reg &= 0xff;
return reg;
}
/**
* message loop.
*/
static void loop() {
if (send) { // send the response
doSend();
} else { // OR check if new msg received
doRcv();
}
}
private static void doRcv() {
int i;
int old485 = cnt485;
while ((JopSys.rd(IO_STATUS)&2)!=0 && cntSer<4) { // @WCA loop=4
bufSer[cntSer++] = JopSys.rd(IO_UART);
msg485 = false;
}
while ((JopSys.rd(IO_STATUS)&32)!=0 && cnt485<4) { // @WCA loop=4
buf485[cnt485++] = JopSys.rd(IO_RS485);
msg485 = true;
}
if (cntSer==4) { // read messages from serial and rs485
for (i=0; i<4; ++i) { // @WCA loop=4
buf485[i] = bufSer[i];
}
cnt485 = 4;
cntSer = 0;
}
if (cnt485==4) {
val = 0;
for (i=0; i<4; ++i) { // @WCA loop=4
val <<= 8;
val |= buf485[i];
}
if (crc(val)==0) { // ignore messages with wrong crc
if (val<0) { // cmds have MSB set
val >>>= 8;
if ((val & ADDR_MSK) == address) {
cmd = val & CMD_MSK;
val &= DATA_MSK;
available = true;
}
}
}
cnt485 = 0;
}
//
// remove bytes if msg not complete after second loop (only RS485)
//
if (old485!=0 && (old485==cnt485)) {
cnt485 = 0;
}
}
private static void doSend() {
int i;
for (i=3; i>=0; --i) { // @WCA loop=4
// buf is filled in 'wrong' way (LSB)
if (msg485) {
JopSys.wr(buf[i], IO_RS485);
} else {
JopSys.wr(buf[i], IO_UART);
}
}
send = false;
}
static int readCmd() {
available = false;
return cmd>>>12;
}
static int readData() {
return val;
}
/**
* write back the answer.
*/
static void write(int val) {
int i;
val &= DATA_MSK; // for shure
val |= address | cmd;
val <<= 8;
val |= crc(val); // append crc
for (i=0; i<4; ++i) { // @WCA loop=4
buf[i] = val & 0x0ff;
val >>>= 8;
}
send = true; // mark buf full, to be sent in next loop
}
/**
* write back error code.
*/
static void err(int val) {
cmd = 0;
write(val);
}
}