Michael Ling
Code to process UI input messages and verify them with checksum.
Diff: UserInterface.cpp
- Revision:
- 0:6b5a3a0138ad
- Child:
- 1:7795fb7ee3f3
diff -r 000000000000 -r 6b5a3a0138ad UserInterface.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/UserInterface.cpp Wed Feb 04 23:53:56 2015 +0000
@@ -0,0 +1,253 @@
+#include "mbed.h"
+#include "MODSERIAL.h"
+#include "initDatabed.h"
+#include "UserInterface.h"
+
+// UI button variables
+//int buttonA = 1; // state of remote button
+//int buttonA_prev = 1;
+
+// push hold vars
+//float tHold = .6; // hold time for sit/stand
+//float tIdle = 2; // time out to confirm sit or stance (s)
+//int SSconfirm = 0; // sit/stand variable for confirmation process
+//float tRelease = .3; // time since last transmission to determine button release
+
+
+// various timers
+//Timer time_StateChange;
+//Timer time_pressA;
+//Timer time_pressB;
+
+//int buttonB = 1; // state of remote button
+//int buttonB_prev = 1;
+//char __xbeeBuffer[250];
+//int _dataCnt=0;
+int UI = 0;
+
+//float _time_sinceA, _time_sinceB; //time since the button was first pressed
+
+UserInterface::UserInterface(void): _buttonA(1), _buttonA_prev(1), _tHold(.6), _tIdle(2), _SSconfirm(0), _tRelease(.3), _buttonB(1), _buttonB_prev(1), _dataCnt(0) {
+}
+
+void UserInterface::readBuffer()
+{
+ while (xbeeUI.readable() && _dataCnt<250) {
+ _xbeeBuffer[_dataCnt] = xbeeUI.getc();
+ _dataCnt++;
+ }
+}
+
+/**
+* This function returns an array of information about the received characters. count[0] is # of data bytes, count[1] is expected length of the message, given the data length bytes and presence
+* of escape characters. count[2] is position of the first data byte.
+* @param idx char array containing received data, beginning with the start byte 0x7e
+* @param count array that will contain the returned values
+* @author Michael Ling
+* @date 2/2/2015
+*/
+void UserInterface::find_length(char *idx, int *count)
+{
+ int pos = 0;
+ short length;
+ //This segment reads the length bytes (bytes 2-3 of the message)
+ if (*(idx+1) == 0x7d) {
+ length = (*(idx+2) ^ 0x20) << 8;
+ pos = 3;
+ } else {
+ length = *(idx+1) << 8;
+ pos = 2;
+ }
+ if (*(idx+pos) == 0x7d) {
+ length = length | (*(idx+pos+1)^0x20);
+ pos += 2;
+ } else {
+ length = length | *(idx+pos);
+ pos += 1;
+ }
+ count[0] = (int)length;
+ //Length incremented by 1--we treat the checksum as a data byte, since it can also be escaped
+ length += 1;
+ //Checks for escape characters--for every escape char found, the data section gets 1 byte longer
+ for (short i = 0; i < length; i += 1) {
+ if (*(idx+i) == 0x7d) {
+ length += 1;
+ }
+ }
+ count[1] = (int) length + 3;
+ count[2] = pos;
+}
+
+/**
+* This function returns true if calculated checksum matches the checksum at the end of the message.
+* @param idx char array containing received data, starting with start byte 0x7e
+* @param length number of data bytes in the message
+* @author Michael Ling
+* @date 2/2/2015
+*/
+bool UserInterface::checksum_check(char *idx, int length)
+{
+ int pos = 0;
+ int sum = 0;
+ for(int i = 0; i < length; i++) {
+ //In case of an escape character, the true value of the byte is the following byte XOR with 0x20
+ if (*(idx+pos) == 0x7d) {
+ sum += (*(idx+pos+1) ^ 0x20);
+ pos += 2;
+ } else {
+ sum += *(idx+pos);
+ pos += 1;
+ }
+ }
+ //XBEE checksum: sum all data bytes, truncate the sum to the rightmost 8 bytes, and subtract that from 0xff
+ sum = sum & 0x0ff;
+ char calcsum = (char)(0xff - sum);
+ char checksum;
+ if (*(idx+pos) == 0x7d) {
+ checksum = *(idx+pos)^0x20;
+ } else {
+ checksum = *(idx+pos);
+ }
+ if (checksum != calcsum) {
+ return false;
+ }
+ return true;
+}
+
+void UserInterface::checkUI_XBee()
+{
+ int sum = 0;
+ _buttonA_prev = _buttonA;
+ _buttonB_prev = _buttonB;
+ char * idx = strchr(_xbeeBuffer,0x7e);
+ if (idx != NULL) {
+ int size[3];
+ find_length(idx, size);
+ pc.printf("Size: %d, Datacount: %d\r\n", size[1], _dataCnt);
+ if(_dataCnt >= size[1]) {
+
+ _buttonA = (_xbeeBuffer[idx-_xbeeBuffer+21]>>1) & 1; // on DIO1
+ _buttonB = (_xbeeBuffer[idx-_xbeeBuffer+21]>>2) & 1; // on DIO2
+
+ if (checksum_check(idx+size[2], size[0])) {
+ pc.printf("Checksums match\r\n");
+ } else {
+ pc.printf("Checksums don't match\r\n");
+ }
+ _dataCnt = 0;
+ }
+ if(sum == 0x79c) {
+ if (_buttonA == 0 && _buttonA_prev == 1) {//buton was just pressed
+ _time_pressA.reset();
+ _time_pressA.start();
+ _time_sinceA = 0;
+ }
+
+ else if(_buttonA == 0) {
+ _time_sinceA = _time_pressA; //button is still pressed
+ }
+
+ if (_buttonB == 0 && _buttonB_prev == 1) {//button was just pressed
+ _time_pressB.reset();
+ _time_pressB.start();
+ _time_sinceB = 0;
+ } else if(_buttonB == 0) {
+ _time_sinceB = _time_pressB; //button is still pressed
+ }
+ }
+
+ if((_time_pressA-_time_sinceA) >= _tRelease) { //button was released
+ if(_time_pressA-_tRelease >= _tHold) { //if the button was held before released
+ UI = 3; //UI command is a held A button
+ } else {
+ UI = 1; //UI command is a pressed A button
+ }
+ _buttonA = 1; //button A is released
+ _time_pressA.stop(); //reset the button A timer
+ _time_pressA.reset();
+ }
+ if(_time_pressB-_time_sinceB >= _tRelease) { //button was released
+ if(_time_pressB-_tRelease >= _tHold) { //if the button was held before released
+ UI = 4; //UI command is a held B button
+ } else {
+ UI = 2; //UI command is a pressed B button
+ }
+ _buttonB = 1; //button B is released
+ _time_pressB.stop(); //reset the button B timer
+ _time_pressB.reset();
+ }
+ }
+ memset(_xbeeBuffer,0xFF,250);
+ _dataCnt = 0;
+}
+
+/*void checkUI_XBee()
+{
+
+ _buttonA_prev = _buttonA;
+ buttonB_prev = buttonB;
+ while (xbeeUI.readable() && _dataCnt<250) {
+ __xbeeBuffer[_dataCnt] = xbeeUI.getc();
+ _dataCnt++;
+ if (__xbeeBuffer[_dataCnt]==0x7e) {
+ for(int i=0; i<22; i++) {
+ if(xbeeUI.readable() {
+ __xbeeBuffer[_dataCnt] = xbeeUI.getc();
+ _dataCnt++;
+ }
+ }
+ }
+ char * idx=strchr(__xbeeBuffer,0x7e);
+ _buttonA = (_xbeeBuffer[idx-_xbeeBuffer+21]>>1) & 1; // on DIO1
+ buttonB = (_xbeeBuffer[idx-_xbeeBuffer+21]>>2) & 1; // on DIO2
+ pc.printf("%x\r\n", *(idx+2));
+ _dataCnt=0;
+ if (buttonA == 0 && buttonA_prev==1) {//buton was just pressed
+ time_pressA.reset();
+ time_pressA.start();
+ _time_sinceA=0;
+ }
+
+ else if(buttonA==0) {
+ _time_sinceA=time_pressA; //button is still pressed
+ }
+
+ if (buttonB == 0 && buttonB_prev==1) {//button was just pressed
+ time_pressB.reset();
+ time_pressB.start();
+ _time_sinceB=0;
+ } else if(buttonB==0) {
+ _time_sinceB=time_pressB; //button is still pressed
+ }
+ }
+ if((time_pressA-_time_sinceA)>=tRelease) { //button was released
+ if(time_pressA-tRelease>=tHold) { //if the button was held before released
+ UI=3; //UI command is a held A button
+ } else {
+ UI=1; //UI command is a pressed A button
+ }
+ buttonA=1; //button A is released
+ time_pressA.stop(); //reset the button A timer
+ time_pressA.reset();
+ }
+ if(time_pressB-_time_sinceB>=tRelease) { //button was released
+ if(time_pressB-tRelease>=tHold) { //if the button was held before released
+ UI=4; //UI command is a held B button
+ } else {
+ UI=2; //UI command is a pressed B button
+ }
+ buttonB=1; //button B is released
+ time_pressB.stop(); //reset the button B timer
+ time_pressB.reset();
+ }
+
+ _dataCnt=0;
+ memset(__xbeeBuffer,0xF,250);
+}*/
+
+void UserInterface::initializeUI()
+{
+ xbeeUI.baud(115200);
+ mainPower = 0;
+
+}