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Lab. 1 – Required Tasks.
For more details – see the Lab. 1 web-site
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Laboratory 1 – Tasks
1. Download the C++ Talk-through program. Board check -- Check that you can hear the audio output
2. Develop and test the code for initializing the Flash Memory and writing to the LED’s
Use the provided tests to check your code
3. Routine for initializing the PF GPIO lines (programmable flags)
Use the provided tests to check your code
4. Develop the ReadProgrammableFlagsASM( ) to read the switches
Use the provided tests to check your code
5. Develop the Morse code program in C++ and ASM
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Set up for Task 1
AUDIO-IN
AUDIO-OUT
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Task 1Download audio-talk-through program If you have not already done so, download and expand
ENCM415Directory2007.zip file so that you have the correct directory. structure and test driven development environment needed for Laboratory 1 and Assignments1.
Download and expand the files in 07CPP_Talkthrough.zip into your AudioDemo directory.
Build an AudioDemo Blackfin project in your AudioDemo directory and add the (provided) files into the project -- compile and link.
Download the executable (.dxe) file onto the BF533 processor.
Hook up your CD or IPOD output to the CJ2 stereo input. Hook up your ear-phones to the CJ3 stereo output. Run the AudioDemo.dxe executable and check that the talk through
program is working.
This task demonstrated your ability to build VDSP Blackfin projects and run the code.
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Question What is a “talk-through program”?
Clear example of applying the first two rules of assembly language programming
Rule 1: If you have a choice – don’t use assembly code It takes as much time (and SOST) to “design, code,
review, test and maintain” one line of C++ code as it does assembly code, but one line of C++ often can do more
Rule 2: If somebody has a working example, cannibalize it for your own work (if legal)
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The talk through program (C++)Prepare to run C++ code
(before you get to main( ))
Set up the EBIUExternal Bus Unit
Use EBIUto initialize A/D and D/A
SET UP theA/D and D/A interrupts
while (1) {/* Wait for messages */ }
ACTIVATE the A/D and D/A interrupts
Every1 / 44,000 s
Store A/D register value(DMA) into memory
Call ProcessDataCPP( )or ProcessDataASM( )
Load memory (DMA) into D/A register
Set messages and flagsto main( )
main( ) ISR -- Interrupt Service Routine
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main( )
int main(void){
sysreg_write(reg_SYSCFG, 0x32); //Initialize System Configuration Register
Init_EBIU();Init_Flash();Init1836();Init_Sport0(); // Serial PORTInit_DMA();Init_Sport_Interrupts();Enable_DMA_Sport0(); // Serial PORT
while (1) { /* */ }}
The system prepares theprocessor to run
C++ code(before you get to main( ))
Set up the EBIUExternal Bus Unit
Use EBIUto initialize A/D and D/A
SET UP theA/D and D/A interrupts
while (1) {/* Wait for messages */ }
ACTIVATE the A/D and D/A interrupts
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ProcessDataCPP( )
#include "Talkthrough.h"
extern volatile int iChannel0LeftIn, iChannel0LeftOut;void Process_DataCPP(void){
iChannel0LeftOut = iChannel0LeftIn;iChannel0RightOut = iChannel0RightIn;iChannel1LeftOut = iChannel1LeftIn;iChannel1RightOut = iChannel1RightIn;
}
TASK 1 – Download the Talkthrough program and check that it works
Voice-activated radio-controlled car works by modifying the ProcessData( ) subroutine
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Building a voice activated radio controlled car -- 4 Threads at least
SWITCHES ON FRONT PANEL“INPUT COMMANDS:
PROGRAMMABLE FLAGS
FIO_FLAG_D Register
YOUR PROGRAM RUNNING ON THE BLACKFIN
LED LIGHTS ON FRONT PANEL“CONTROLSIGNALS TO RF TRANS:
LED-CONTROLREGISTER
EBIU INTERFACE
ProcessDataASM( ) subroutine
A/D D/A Interrupt routine D/AEAR
PHONESA/DVOICE
int ReadSwitches( ) void WriteLED(int )
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Set-up for “Laboratory 1” interfacing.“Make the switches work”1. De-activate Visual DSP2. Power down Blackfin3. Connect power to “special Blackfin interface”
connector4. Connect 50-pin cable to logic-lab5. Connect 50-pin cable to Blackfin6. Power up logic lab. station7. Power up Blackfin8. Reactivate Visual DSP9. Check that station works using “Lab. 1 test-executable”
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Special “power-connector” for Blackfin interface on logic lab. station
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Special “power-connector” for Blackfin interface on logic lab. station
Picture of the “power connector” taken with a camera with a finger-print on the lens. Check that has not been stolen. Extras in your lab. kit is needed (perhaps)
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Connect 50-pin cable to Blackfin
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Connect 50-pin cable to logic lab
Make sure that all 50-pin connections are secure and proper.
Power up the logic lab. station and check that is working – toggle switches and LEDs
CHEK each lab. As fuses can just wear out
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Task – Initialize the Programmable flag interface – 16 I/O lines on the Blackfin
Warning – could burn out the Blackfin processor if done incorrectly
You need to set (store a known value to) a number of Blackfin internal registers
Most important onesFIO_DIR – Data DIRection – 0 for input ****FIO_INEN – INterface ENable – 1 for enabledFIO_FLAG_D – Programmable FLAG Data register
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Why do you need to know how to do read (load) and write (store) on internal registers?
Flag Direction register (FIO_DIR) Used to determine if the PF bit is to be used for input or
output -- WARNING SMOKE POSSIBLE ISSUE Need to set pins PF11 to PF8 for input, leave all other pins
unchanged
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Write the Blackfin assembly language instruction(s) to load the address of the internal programmable flag FIO_DIR register into pointer register P1 – then SET the Blackfin PF lines to act as inputs
#include <defsBF533.h>
#include <macros.h>P1.L = lo (FIO_DIR);
P1.H = hi (FIO_DIR);
// Check the requirements – need to have all input
// Manual says “setting a line for input means setting FIO_DIR bit values to 0”
R0 = 0;
W[P1] = R0; // This changes “All pins”
ssync; // Force Blackfin to do the write (store) operation NOW not later
Making sure that the FIO_DIR is correct for LAB. 1 – NOTE may need to change for later labaoratories
Design Error
“Changes all pins
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P1.L = lo (FIO_DIR); // #include <defsBF533.h> “knows” FIO_DIR value
P1.H = hi (FIO_DIR);
// R0 = 0; // DESIGN ERROR – changes all pins to 0
// W[P1] = R0; // This changes “All pins”
// Correct approach – use an AND mask operation
// Read the current value
// Prepare the 32-bit mask with bits // 8 to 11 set to 1, other bits 0
// Complement operation
// bits 8 to 11 are 0, other bits 1
// R3 bits = 0 for bits 8 to 11;
// R3 bits = FIO_DIR bits otherwise
// Restore FIO DIR with bits 8 to 11 set to 0,
ssync; // Force Blackfin to do the write (store) NOW not later
Setting FIO_DIR to zero for “ONLY” pins 8, 9, 10 and 11. Other pins unchanged
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Registers used to control PF pins
Flag Input Enable Register Only activate the pins you want to use (saves power in
telecommunications situation) Need to activate pins PF11 to PF8 for input, leave all other pins
unchanged
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Write the Blackfin assembly language instruction(s) to load the address of the internal programmable flag FIO_INEN register into pointer register P1 – then ENABLE the Blackfin PF lines as inputs
#include <defsBF533.h>
#include <macros.h>P1.L = lo (FIO_?????);
P1.H = hi (FIO_?????);
// Check the requirements – need to have all input
// Manual says “setting a line for input means setting bit values to 0”R0 = 0x0F00;
W[P1] = R0; // This changes “All pins” 8 to 11 ON (enable), others OFF
ssync; // Force Blackfin to do the write (store) NOW not later
Making sure that the FIO_INEN is correct for enable of pins 8 to 11
Design Error
“Changes all pins
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P1.L = lo (FIO_???); // #include <defsBF533.h> “knows” FIO_INEN value
P1.H = hi (FIO_???);
// R0 = 0x0F00; // DESIGN ERROR – changes all pins
// W[P1] = R0; // This changes “All pins”
// Correct approach – use an AND mask operation
// Read the current value
// Prepare the 32-bit mask with bits // 8 to 11 set to 1, other bits 0
// R3 bits = 1 for bits 8 to 11;
// R3 bits = FIO_DIR bits otherwise
// Restore FIO INEN with bits 8 to 11 set to 1,
ssync; // Force Blackfin to do the write (store) NOW not later
Setting FIO_INEN to one for “ONLY” pins 8, 9, 10 and 11. Other pins unchanged
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Registers used to control PF pins
Flag Data register (FIO_FLAG_D) Used to read the PF bits as an input -- (1 or 0) Need to read pins PF11 to PF8, ignore all other pins values
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Task – Setting up the programmable flag interfaceFollow the instructions carefullyFIO_DIR – direction register – write 0’s to bits 8 to 11FIO_INEN – input enable register – write 1’s to bits 8, 9,
10, 11Other registers “bits” leave “unchanged:There are 6 registers in total
To provide a screen dump of the test result to show your code works Use PRT-SCR button and then paste in .doc file.
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#include <defsBF533.h>
#include <macros.h>
.global _ReadBlackfinGPIOFlags__Fv;
_ReadBlackfinGPIOFlags__Fv
LINK 16;
P1.L = lo (FIO_FLAG_D); // could be P0
P1.H = hi (FIO_FLAG_D);
R0 = W[P1] (Z);
P0 = [FP + 4];
UNLINK;
_ReadPBlackfinGPIOFlags__Fv; JUMP (P0);
Must use W [ ]since the manual shows that FIO_FLAG_D register is 16-bits
Must use W[P1] (Z) zero-extend as this adds 16 zeros to the 16 bits from FIO_FLAG_D register to make 32-bits to place into R0
int ReadBlackfinGPIOFlagsASM( )
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How to use int ReadBlackFinGPIOFlagsASM( )
int GPIO_setting = ReadBlackfinGPIOFlagsASM( );SWITCHES ON FRONT PANEL
PROGRAMMABLE FLAGS
FIO_FLAG_D Register
int ReadSwitches( )
(FIO_POLAR register = 0)
All switches unpressed
Binary Pattern in FIO_FLAG_D register
B ????0000????????
All switches pressed
Binary Pattern in FIO_FLAG_D registerB ????1111????????
Binary ? Means – we don’t know what the answer is
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How to use int ReadBlackfinGPIOFlagsASM( )
int GPIO_setting = ReadBlackfinGPIOFlagsASM( );SWITCHES ON FRONT PANEL
PROGRAMMABLE FLAGS
FIO_FLAG_D Register
int ReadSwitches( )
(FIO_POLAR register = 0)
All switches unpressed
Binary Pattern in FIO_FLAG_D register
B XXXX0000XXXXXXXX
All switches pressed
Binary Pattern in FIO_FLAG_D registerB XXXX1111XXXXXXXX
Binary X Means – we don’t know what the answer is – and don’t care
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Echoing the switches to the LEDCode in main( ) – written in C++
int main( ) {
InitializeGPIOInterface( ); // Check Lab. 1 for “exact name needed”InitializeFlashLEDInterface( ); // Check Lab. 1 for “exact name needed”
#define SWITCHBITS 0x0F00 // Look in MIPs notes about // using a mask and the // AND bit-wise operation
// to select “desired bits” while (1) { // Forever loop int GPIO_value = ReadBlackfinGPIOFlagsASM ( );
int desired_bits = GPIO_value & SWITCHBITS;
int LED_light_values = desired_bits >> 8; // Bits in wrong position
WriteFlashLEDLights(LED_light_values); // to display on LEDS
}
}
Avoid this common mistake
Many seem to think that the switch routine returns 1 is SW1 is pressed, 2 if SW2 is pressed, 3 if SW3 is pressed.
This is NOT correct as the switch routine has to be able to return 16 different values
Value meaning SW1 pressed, SW2, SW3, SW4 not pressed (0x0100)
Value meaning SW1 and SW4 pressed with SW2 and SW3 not pressed (0x0900)
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Practice example -- Rewrite the code so that loop stops if all the switches are pressed at the same time
int main( ) {
InitializeSwitchInterface( ); // Check Lab. 1 for “exact name needed”InitializeLEDInterface( );
????
#define SWITCHBITS 0x0F00 // Looking in MIPs notes about MASKS
while (???? ) { // conditional loop int GPIO_value = Read ReadBlackfinGPIOFlagsASM ( );
int desired_bits = GPIO_value & SWITCHBITS;
int LED_light_values = desired_bits >> 8; // Bits in wrong position
WriteFlashLEDLightsASM(LED_light_values);
????
}
}
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Laboratory 1 – Tasks
1. Download the C++ Talk-through program. Board check -- Check that you can hear the audio output
2. Develop and test the code for initializing the Flash Memory and writing to the LED’s
Use the provided tests to check your code
3. Routine for initializing the PF GPIO lines (programmable flags)
Use the provided tests to check your code
4. Develop the ReadProgrammableFlagsASM( ) to read the switches
Use the provided tests to check your code
5. Develop the Morse code program in C++ and ASM
