T H _ J T A G

Good first training practice : Have your LEDs flashing

Step 1 : Create a function : Word My_Function ( void )

Word My_Function (void) { return 0; } Nothing really hard so far !

Step 2 : Create the LED driving JTAG bus

A minimum of 2 buses are needed :
• One output bus ( to drive a logic level on the physical pin )
• One control bus ( to validate the output JTAG cell )
• One optional input bus to monitor the drive pin (verify the output data)

What is called "bus" is a set of JTAG cells. In this textbook case the bus will be formed with only one cell. Bus my_bus_out("my_bus_out", &board); my_bus_out.BusInit(1, &(board.mn43.io_out), 30, 30); In the first line à a bus named "mon_bus_out" is created.
Parameters are a caracter string with the real name ( user free ) and a reference to the board (default is "&board" ).

Next thing to do is to initialise the bus and attach him the proper JTAG cells. This initialisation is done by "BusInit".
The first parameter is the number of triplets "LABEL_PORT, CELLULE MSB, CELLULE LSB".
The second parameter is the JTAG cell(s) included in the bus ( here , a reference on io_out port of mn43 component, with cell number 30 ).

The same thing is to be done with the control cell : Bus my_bus_ctl("my_bus_ctl", &board); my_bus_ctl.BusInit( 1, &(board.mn43.io_ctl), 30, 30); And now, I can use the new buses.

Step 3 : Make the led blinking

The component must be first put in Extest mode, but be aware that others JTAG cells are in disable mode ! board.mn43.Sample(); Scan(IR); // boundary is activated in spy mode. Scan(IR) as it is an instruction board.mn43.Disable(); Scan(DR); // boundary scan control cells are set in a safe state. Scan(DR) as it is a data (Bscan register) board.mn43.Extest(); Scan(IR); // BSCAN component moves up to Extest mode, with all output cells maintained in H-Z state. Last step is to activate blinking : my_bus_ctl.Cpl(); Scan(DR); // invert the control cell (activate output) for(int i = 0; i < 10 ; i++) { my_bus_out.Cpl(); // invert output LED data Scan(DR); } If you can do that : You can do every thing that is possible with JTAG ... Now it's your turn .

const char * ReadValueFromADC (Bus &RNC, Bus &NCS, Bus &HBE, Bus &DB, Bus &NBUSY, Bus &MANA_MUX_EN, Bus &MUX_SEL_VOIE, unsigned short voie, unsigned short ActiveMux) { //Conversion channel selection MUX_SEL_VOIE = channel; // activate ADC NCS.Clr(); // HBE deasserted (0) HBE.Clr(); //Scan(DR); RNC.Set(); Scan(DR); //wait a little bit Sleep(10); // control deasserted (0) RNC.Clr(); Scan(DR); Sleep(10); //control asserted (1) RNC.Set(); Scan(DR); Sleep(50); //read inputs Scan(DR); //wait a little bit while ADC conversion is in progress while (!NBUSY.Receive(0)) Scan(DR); // desactivate ADC NCS.Set(); Scan(DR); // send back conversion result to the application return DB.Receive(); }

WORD WriteValueOnDAC (Bus &SelRgtInput, Bus &RNW, Bus &NCS, Bus &RST, Bus &RSTSEL, Bus &LDAC, Bus &DB, char ActiveDACs, long value, long DefaultValue, char ActiveComponents) { char tmpActiveDACs = ActiveDACs; //make reset RSTSEL.Clr(); RST.Clr(); Scan(DR); RST.Set(); Scan(DR); //activate the components char maskNbComponents = 0; for (int inc = 0; inc < NCS.NbCell(); inc++) maskNbComponents += (1 << inc); NCS = (~ActiveComponents) & maskNbComponents; //reset the mask of activated DACs ActiveDACs = tmpActiveDACs; //load the value in each input register for (int nDAC = 0; nDAC < pow(2, SelRgtInput.NbCell()); nDAC++) { if (ActiveDACs % 2) { DB = value; } else { DB = DefaultValue; } SelRgtInput = nDAC; Scan(DR); RNW.Clr(); Scan(DR); RNW.Set(); Scan(DR); ActiveDACs >>= 1; } // write default value on non-activated components NCS = (ActiveComponents) & maskNbComponents; Scan(DR); //reset the mask of activated DACs ActiveDACs = tmpActiveDACs; //load the value in each input register for (nDAC = 0; nDAC < pow(2, SelRgtInput.NbCell()); nDAC++) { DB = DefaultValue; SelRgtInput = nDAC; Scan(DR); RNW.Clr(); Scan(DR); RNW.Set(); Scan(DR); ActiveDACs >>= 1; } //update the ouputs NCS.Set(); LDAC.Clr(); Scan(DR); LDAC.Set(); Scan(DR); //wait conversion Sleep(20); return (RTN_OK); }