/*

	================================================================================

	This program controls Asuro by received IR (InfraRed) signals.
	Use Hyperterminal and left/right/up/down keys to control Asuro.
	When arrowkeys are pressed they will send 3 charaters each time.
	1. 0x1B
	2. 0x5B
	3. 0x41 (up), 0x42 (down), 0x43 (right), 0x44 (left)
	Only if all 3 characters are received the engines will drive.
	Each time the Asuro USART receives a character, an interrupt is executed
	This interrupt function (handler) handles the received character

	===============================================================================//

	Program       : Asuro 019, Build 001, Asuro controlled by hyperterminal arrow keys.c
	Release date  : 2005-02-14
	Author        : Henk van Winkoop

	Build					: 001, 2005-02-14, original release

	================================================================================
*/
//--------------------------------------------------------------------------------
//	INCLUDES
//--------------------------------------------------------------------------------
#include "hvwdefines.h"
//--------------------------------------------------------------------------------
//	GLOBALS
//--------------------------------------------------------------------------------
unsigned char gucRcvChrCnt;
//================================================================================
//  DELAY MILLI SECONDS
//================================================================================
void vDelayXMilliSeconds(int iDelMilSec){
	//var
	unsigned int i,j;
	//handle all milli seconds
	for(i=0;i<iDelMilSec;i++){
		//delay 1 millisecond
		for(j=0;j<28750;j++){
		}//for
	}//for
}
//================================================================================
//	INIT ALL PORTS AS INPUTS AND OUTPUTS
//================================================================================
void vInitAllPortsAsInputsAndOutputs(void){

  //disable all output pull-up resistors
  //SFRX(SFIOR,PUD_H);

  //+-------------------------------------------------------------------------------------------+
  //| DDRB =  Data Direction Register port B                                                    |
  //|                                                                                           |
  //| FWD_RGT = Forward Right engine                                                            |
  //| REV_RGT = Reverse Right engine                                                            |
  //| IR1_TXD = InfraRed Transmit data (connection1, connected to R16) carrier input            |
  //| SPD_RGT = Speed of Right engine                                                           |
  //| SPD_LFT = Speed of Left engine                                                            |
  //| SLD_GRN = System LeD Green                                                                |
  //+-------------------------------------------------------------------------------------------+
  //| right engine off, ir-tx carrier off, left/right engine speed zero, green system led off   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|port name  |   PB7   |   PB6   |   PB5   |   PB4   |   PB3   |   PB2   |   PB1   |   PB0   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |    2    |    1    |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|pin number |   10    |    9    |   19    |   18    |   17    |   16    |   15    |   14    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name|  XTAL2  |  XTAL1  |REV_RGT_X|FWD_RGT_X|IR1_TXD_X|SPD_RGT_X|SPD_LFT_X|SLD_GRN_X|
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( DDRB   ,RESERVED |RESERVED |REV_RGT_O|FWD_RGT_O|IR1_TXD_O|SPD_RGT_O|SPD_LFT_O|SLD_GRN_O);
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( PORTB  ,RESERVED |RESERVED |REV_RGT_H|FWD_RGT_H|IR1_TXD_L|SPD_RGT_L|SPD_LFT_L|SLD_GRN_L);
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //                 x         x         .         .         .         .         .         .    = unused (connected to 8MHz Xtal)
  //                 .         .         n         n         .         .         .         .    = OL OL = both engine poles connected to VCC (break?)
  //                 .         .         n         n         .         .         .         .    = OL OH = set right engine direction to reverse
  //                 .         .         n         n         .         .         .         .    = OH OL = set right engine direction to forward
  //                 .         .         OH        OH        .         .         .         .    = OH OH = both engine poles disconnected from VCC
  //                 .         .         .         .         OL        .         .         .    = Infra Red transmit signal
  //                 .         .         .         .         .         OL        OL        .    = left-engine and right-engine speed output inactive
  //                 .         .         .         .         .         .         .         OL   = system-led green-light control output, OFF
  //+-------------------------------------------------------------------------------------------+

  //+-------------------------------------------------------------------------------------------+
  //| DDRC =  Data Direction Register port C                                                    |
  //|                                                                                           |
  //| VPL_SNS = V+ Sense                                                                        |
  //| SWI_JNC = Switch Junction                                                                 |
  //| TRS_LFT = Tracksensor Left                                                                |
  //| TRS_RGT = Tracksensor Right                                                               |
  //| BOD_LFT = Break and Odometer Left                                                         |
  //| BOD_RGT = Break and Odometer Right                                                        |
  //+-------------------------------------------------------------------------------------------+
  //| supply voltage measurement enable, switch detection by interrupt enable,                  |
  //| left/right track sensors enable, left/right break leds enable                             |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|port name  |   PC7   |   PC6   |   PC5   |   PC4   |   PC3   |   PC2   |   PC1   |   PC0   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|pin number |    -    |    1    |   28    |   27    |   26    |    25   |    24   |   23    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name|    -    |  RESET  |VPL_SNS  |SWI_JNC  |TRS_LFT  |TRS_RGT  |BOD_LFT  |BOD_RGT  |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( DDRC   ,RESERVED |RESERVED |VPL_SNS_I|SWI_JNC_I|TRS_LFT_I|TRS_RGT_I|BOD_LFT_O|BOD_RGT_O);
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( PORTC  ,RESERVED |RESERVED |VPL_SNS_N|SWI_JNC_N|TRS_LFT_N|TRS_RGT_N|BOD_LFT_L|BOD_RGT_L);
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //                 .         .         IN        .         .         .         .         .    = V+ sensor measurement as input
  //                 .         .         .         IN        .         .         .         .    = key-press detector as input
  //                 .         .         .         .         IN        IN        .         .    = left/right track sensors as input
  //                 .         .         .         .         ,         ,         OL        OL   = left/right break/odo-meter sensors as input
  //+-------------------------------------------------------------------------------------------+

  //+-------------------------------------------------------------------------------------------+
  //| DDRD =  Data Direction Register port D                                                    |
  //|                                                                                           |
  //| BOD_COM = Breaks and Odoleds Common connection                                            |
  //| TRK_LED = Track Led                                                                       |
  //| FWD_LFT = Forward Left engine                                                             |
  //| REV_LFT = Reverse Left engine                                                             |
  //| SWI_IAC = Switches Interrupt And Control                                                  |
  //| SLD_RED = System Led Red                                                                  |
  //| IR2_TXD = InfraRed Transmit data (connection2, connected to D10) modulation input         |
  //| IR_RXD  = InfraRed Receive data                                                           |
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| enable breakleds, trackled off, left engine off, switch sensor enable,                    |
  //| red system led off, tx-ir modulator off, rx-ir enable                                     |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|port name  |   PD7   |   PD6   |   PD5   |   PD4   |   PD3   |   PD2   |   PD1   |   PD0   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|pin number |   13    |   12    |   11    |    6    |    5    |     4   |     3   |    2    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name|BOD_COM_X|TRK_LED_X|REV_LFT_X|FWD_LFT_X|SWI_IAC_X|SLD_RED_X|IR2_TXD_X|IR_RXD_X |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( DDRD   ,BOD_COM_O|TRK_LED_O|REV_LFT_O|FWD_LFT_O|SWI_IAC_I|SLD_RED_O|IR2_TXD_O|IR_RXD_I ); 
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( PORTD  ,BOD_COM_L|TRK_LED_L|REV_LFT_H|FWD_LFT_H|SWI_IAC_N|SLD_RED_L|IR2_TXD_H|IR_RXD_N ); 
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //                 OL        .         .         .         .         .         .         .    = both odometrie leds (#001)
  //                 .         OL        .         .         .         .         .         .    = front (tracking) led (#002)
  //                 .         .         n         n         .         .         .         .    = OL OL = both engine poles connected to VCC (break?)
  //                 .         .         n         n         .         .         .         .    = OL OH = set left engine direction to reverse
  //                 .         .         n         n         .         .         .         .    = OH OL = set left engine direction to forward
  //                 .         .         OH        OH        .         .         .         .    = OH OH = both engine poles disconnected from VCC
  //                 .         .         .         .         IN        .         .         .    = 'switches' is input
  //                 .         .         .         .         .         OL        .         .    = system-led red-light control output
  //                 .         .         .         .         .         .         OH        IN   = Infra-Red signals both as input
  //+-------------------------------------------------------------------------------------------+

}
//================================================================================
//	INIT USART RECEIVE 2400 8 N 1 USING RX INTERRUPT
//	disable global interrupt when initiating
//================================================================================
void vInitUsartRx2400B8N1UsingRxInterrupt(void){

//+-------------------------------------------------------------------------------------------+
  //| UCSRA =  USART Control and Status Register A                                              |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //| RXC  = Receive  Complete, set, as long as there is unread received data in rx-buffer (UDR)|
  //| TXC  = Transmit Complete, set, if all data from transmit buffer (UDR) is send             |
  //|        cleared automatically if transmit-complete interrupt is executed                   |
  //| UDRE = Usart Data Register Empty, set, if transmit buffer (UDR) is empty (interr: TXCIE)  |
  //| FE   = Frame Error, if (next?) received character stopbit is zero                         |
  //| DOR  = Data OverRun, set, when 2 characters in Receive Buffer, 1 character in Receive     |
  //|        Shift Register, and a new startbit detected.                                       |
  //| PE   = Parity Error, set, if (next?) received character has a parity error. (if enabled)  |
  //| U2X  = Double the USART transmission speed (do set to 0 in normal use)                    |
  //| MPCM = Multi-processor Communication Mode. (do set to 0 in normal use)                    |
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| clear tx-complete flag, no double usart speed, no multi-processor mode                    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |    2    |    1    |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|read/write |    R    |   R/W   |    R    |    R    |    R    |    R    |   R/W   |   R/W   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name|  RXC_X  |  TXC_X  | UDRE_X  |  FE_X   | DORF_X  |  PE_X   |  U2X_X  | MPCM_X  |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( UCSRA  ,            TXC_H                                          |  U2X_L  | MPCM_L  );
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+


  //+-------------------------------------------------------------------------------------------+
  //| UCSRB =  USART Control and Status Register B                                              |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //| RXCIE = Receive  Complete, Interrupt Enable                                               |
  //| TXCIE = Transmit Complete, Interrupt Enable                                               |
  //| UDRIE = Usart Data Register Empty, Interrupt Enable (tx)                                  |
  //| RXEN  = Usart Receiver    ENable                                                          |
  //| TXEN  = Usart Transmitter ENable, (if disabled, first all unsend data will be send)       |
  //| UCSZ2 = number of databits (combined with UCSZ1 and UCSZ0 in UCSRC)                       |
  //| UCSZ2:UCSZ1:UCSZ0                                                                         |
  //|   0     0     0     5-bit                                                                 |
  //|   0     0     1     6-bit                                                                 |
  //|   0     1     0     7-bit                                                                 |
  //|   0     1     1     8-bit                                                                 |
  //|   1     0     0     Reserved                                                              |
  //|   1     0     1     Reserved                                                              |
  //|   1     1     0     Reserved                                                              |
  //|   1     1     1     9-bit                                                                 |
  //| RXB8  = Received data Bit 8 (if 9 databits used)                                          |
  //| TXB8  = Transmit data Bit 8 (if 9 databits used)                                          |
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| rx-int. enable, tx-int. disable, register-empty int. disable, rx enable, tx disable, 8-bit|
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |    2    |    1    |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|read/write |   R/W   |   R/w   |   R/w   |   R/w   |   R/w   |   R/w   |    R    |   R/W   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name| RXCIE_X | TXCIE_X | UDRIE_X | RXEN_X  | TXEN_X  | UCSZ2_X | RXB8_X  | TXB8_X  |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( UCSRB  , RXCIE_H | TXCIE_L | UDRIE_L | RXEN_H  | TXEN_L  | UCSZ2_L           | TXB8_L  );
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+

	//remember(!), - do not use 'SFRX' define with register UCSRC and UBRRH because this define reads register first
	//but reading UCSRC/UBRRH first time will return UBRRH and next time will return UCSRC!
	//if you want to read UCSRC, then read UCSRC/UBRRH twice without any instruction between first and second read operation!

  //+-------------------------------------------------------------------------------------------+
  //| UCSRC =  USART Control and Status Register C                                              |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //| URSEL = Usart Register SELect: 0=read/write UBRRH, 1=read/write UCSRC (=current register!)|
  //|         equals URSEL bit in UBRRH register                                                |
  //| UMSEL = Usart Mode SELect: 0 = asynchronous, 1 = synchronous                              |
  //| UPM1:UPM0 = Usart Parity Mode1:                                                           |
  //|  0    0      Disabled                                                                     |
  //|  0    1      Reserved                                                                     |
  //|  1    0      Enabled, Even Parity                                                         |
  //|  1    1      Enabled, Odd Parity                                                          |
  //| USBS  = Usart StopBit Select: 0 = 1 stopbit, 1 = 2 stopbits                               |
  //| UCSZ1:UCSZ0 = number of databits (combined with UCSZ2 in UCSRB)                           |
  //| UCSZ2:UCSZ1:UCSZ0                                                                         |
  //|   0     0     0     5-bit                                                                 |
  //|   0     0     1     6-bit                                                                 |
  //|   0     1     0     7-bit                                                                 |
  //|   0     1     1     8-bit                                                                 |
  //|   1     0     0     Reserved                                                              |
  //|   1     0     1     Reserved                                                              |
  //|   1     1     0     Reserved                                                              |
  //|   1     1     1     9-bit                                                                 |
  //| UCPOL = Usart Clock POLarity: (only used in synchronous mode)                             |
  //| +---+----------------------------+-------------------------+                              |
  //| |   |  Transmitted Data Changed  |  Received Data Sampled  |                              |
  //| |   |  (Output ofTxD Pin)        |  (Input on RxD Pin)     |                              |
  //| +---+----------------------------+-------------------------+                              |
  //| | 0 |  Rising  XCK               | Edge Falling XCK Edge   |                              |
  //| | 1 |  Falling XCK               | Edge Rising  XCK Edge   |                              |
  //| +---+----------------------------+-------------------------+                              |
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| async mode, no parity, 1 stopbit, 8 databits                                              |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |    2    |    1    |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|read/write |   R/W   |   R/W   |   R/W   |   R/W   |   R/W   |   R/W   |   R/W   |   R/W   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name| URSEL_H | UMSEL_X | UPM1_X  | UPM0_X  | USBS_X  | UCSZ1_X | UCSZ0_X | UCPOL_X |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRW ( UCSRC  , URSEL_H | UMSEL_L | UPM1_L  | UPM0_L  | USBS_L  | UCSZ1_H | UCSZ0_H | UCPOL_L );
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+


  //+-------------------------------------------------------------------------------------------+
  //| UBRRH =  Usart Baud Rate Register High                                                    |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //| URSEL = Usart Register SELect: 0=read/write UBRRH, 1=read/write UCSRC (=current register!)|
  //|         equals URSEL bit in UCSRC register                                                |
  //|                                                                                           |
  //| The Baudrate generator probably uses a 16x prescaler.                                     |
  //| 8MHz clock / prescaler 16 = 2us per counter step, 2400 baud = 417us per bit,              |
  //| To generate 417 bits per second the counter should count to 417us/2us = 208               |
  //| According the .pdf tabel 62, a setting of 207 will do.                                    |
  //| Settings also calculated for other oscillator frequencies and they all match.             |
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| 2400 baud                                                                                 |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |    2    |    1    |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|read/write |   R/W   |    R    |    R    |    R    |   R/W   |   R/W   |   R/W   |   R/W   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name| URSEL_L |RESERVED |RESERVED |RESERVED |UBRR11_X |UBRR10_X |UBRR09_X |UBRR08_X |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( UBRRH  , URSEL_L                               |UBRR11_L |UBRR10_L |UBRR09_L |UBRR08_L );
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+

	
  //+-------------------------------------------------------------------------------------------+
  //| UBRRL =  Usart Baud Rate Register Low                                                     |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| user comments                                                                             |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |    2    |    1    |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|read/write |   R/W   |   R/W   |   R/W   |   R/W   |   R/W   |   R/W   |   R/W   |   R/W   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name|UBRR07_X |UBRR06_X |UBRR05_X |UBRR04_X |UBRR03_X |UBRR02_X |UBRR01_X |UBRR00_X |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRW ( UBRRL  ,                                     0xCF                                      );
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+

}
//================================================================================
//	MAIN
//================================================================================
int main(void){

	//stop the 36KHz timer2 (left active by boot sector) but does not harm anything (default = 0x19)
	//SFRX(TCCR2,CS22_L|CS21_L|CS20_L);

	//init globals
	gucRcvChrCnt=0;

	//init all microprocessor io-ports
	vInitAllPortsAsInputsAndOutputs();

	//general interrupt disable
	SFRX(SREG,GIE_L);

	//init usart receive 2400 8 N 1 using receive interrupt
	vInitUsartRx2400B8N1UsingRxInterrupt();

	//general interrupt enable
	SFRX(SREG,GIE_H);

	//enable both engines for full speed
  SFRX ( PORTB  , SPD_RGT_H | SPD_LFT_H ) ;

	//hang here
	while(1);

	//exit function
	return 0;
	
}

//================================================================================
// interrupt handler, uart receive complete
// enable bit: register UCSRB bit RXCIE
// #define SIG_UART_RECV _VECTOR(11)
// pdf table 18, vector number decimal 12
//================================================================================
SIGNAL(SIG_UART_RECV){
	//var
	unsigned char ucRcvDat;
	//read received byte from i/o register (this will clear the interrupt flag)
	ucRcvDat=UDR;
	//analyse received character
	switch(ucRcvDat){
		//if first arow key character is received
		case 0x1b: 
			//remember: 1 good arrow key character received
			gucRcvChrCnt=1;
			//green system led on
			SFRX ( PORTB , SLD_GRN_H ) ;
			//exit case
		break;
		//if second arow key character is received
		case 0x5b: 
			//red system led on
			SFRX ( PORTD , SLD_RED_H ) ;
			if(gucRcvChrCnt==1){
				//remember: 2 good arrow key characters received
				gucRcvChrCnt=2;
			}//if
			//exit case
		break;
		//if another character is received
		default:
			//if allready two correct arrow key characters were received
			if(gucRcvChrCnt==2){
				//analyse third received character
				switch(ucRcvDat){
					//arrow up
					case 0x41:
						//both engines forward
						SFRX ( PORTD  , REV_LFT_H | FWD_LFT_L ) ; 
						SFRX ( PORTB  , REV_RGT_H | FWD_RGT_L ) ;
						//keep driving for a while
						vDelayXMilliSeconds(100);
						//both engines off
						SFRX ( PORTD  , REV_LFT_H | FWD_LFT_H ) ; 
						SFRX ( PORTB  , REV_RGT_H | FWD_RGT_H ) ;
					break;
					//arrow down
					case 0x42:
						//both engines reverse
						SFRX ( PORTD  , REV_LFT_L | FWD_LFT_H ) ; 
						SFRX ( PORTB  , REV_RGT_L | FWD_RGT_H ) ;
						//keep driving for a while
						vDelayXMilliSeconds(100);
						//both engines off
						SFRX ( PORTD  , REV_LFT_H | FWD_LFT_H ) ; 
						SFRX ( PORTB  , REV_RGT_H | FWD_RGT_H ) ;
					break;
					//arrow right
					case 0x43:
						//left engine forward, right engine reverse
						SFRX ( PORTD  , REV_LFT_H | FWD_LFT_L ) ; 
						SFRX ( PORTB  , REV_RGT_L | FWD_RGT_H ) ;
						//keep driving for a while
						vDelayXMilliSeconds(100);
						//both engines off
						SFRX ( PORTD  , REV_LFT_H | FWD_LFT_H ) ; 
						SFRX ( PORTB  , REV_RGT_H | FWD_RGT_H ) ;
					break;
					//arrow left
					case 0x44:
						//left engine reverse, right engine forward
						SFRX ( PORTD  , REV_LFT_L | FWD_LFT_H ) ; 
						SFRX ( PORTB  , REV_RGT_H | FWD_RGT_L ) ;
						//keep driving for a while
						vDelayXMilliSeconds(100);
						//both engines off
						SFRX ( PORTD  , REV_LFT_H | FWD_LFT_H ) ; 
						SFRX ( PORTB  , REV_RGT_H | FWD_RGT_H ) ;
					break;
				}//switch
			}//if
			//assume: 3 valid arrow key character received, ready for new sequence
			gucRcvChrCnt=0;
			//green system led of
			SFRX ( PORTB , SLD_GRN_L ) ;
			//red system led of
			SFRX ( PORTD , SLD_RED_L ) ;
	}//switch
}