1. Multi-Threaded Systems
TI BIOS CLK-PRD
Multi-Threaded Systems
17 November 2018
Dr. Veton Këpuska

2. Why DSP/BIOS
For most system developers today, more time is spent on software design than on hardware design. This is mainly due to the fact that most of the complex hardware functions are already integrated into standard integrated circuits.
System developers simply need to select the right chip to do the right job.
System designers can use either dedicated hardware integrated circuits or programmable DSPs to implement DSP functions.
17 November 2018
Dr. Veton Këpuska

3. Why DSP/BIOS The advantages of programmable DSPs are:
Scalability – Designers can first decide how much processing power (or MIPS—million instructions per second), memories, and other resources are required to do a certain job, then select the DSP with enough processing resources. If one DSP is not enough, more DSPs can be added until the required processing resources are met.
Upgradability – Even after the hardware design is fixed, any change in DSP functions can be implemented easily by making changes in software, and downloading the change to the DSP in seconds.
17 November 2018
Dr. Veton Këpuska

4. Why DSP/BIOS
However, compared to dedicated hardware DSP chips to implement DSP functions, programmable DSPs need to manage their resources so that they can be shared among different DSP functions.
Hardware resources include the CPU, memory, and peripherals.
17 November 2018
Dr. Veton Këpuska

5. Why DSP/BIOS
CPU-sharing – In most systems, the number of DSP functions is much larger than the available number of CPUs. Thus, each CPU must be time-shared among DSP functions. But time-sharing the CPU may cause a critical DSP function to miss its real-time deadline. DSP/BIOS and Code Composer Studio are the tools to make time-sharing CPU much easier and avoid real-time deadline problems.
17 November 2018
Dr. Veton Këpuska

6. Why DSP/BIOS
Memory-sharing – Memory-sharing is usually the responsibility of the algorithm developer. Using the C language, static memories can be managed easily. However, when the system gets complex with lots of DSP functions, it is not efficient to store each algorithm’s scratch memory statically. Texas Instruments eXpress DSP Algorithm Standard (xDAlS) addresses this issue. The xDAlS is out of the scope of this application report.
Peripheral-sharing – In most cases, such as I/O devices, a peripheral can be handled by a dedicated DSP function, which is called a device driver. Peripherals such as the direct memory access controller (DMAC) can also be handled this way.
17 November 2018
Dr. Veton Këpuska

7. Why DSP/BIOS
With DSP/BIOS, system designers can develop their DSP systems on programmable DSPs using block diagrams to block out each DSP function, similar to designing using dedicated DSP hardware integrated circuits.
As mentioned earlier, DSP/BIOS allows system designers to do two major tasks:
real-time monitoring and control, and
real-time scheduling and communication.
DSP/BIOS provides modules to accomplish these tasks (see Table 1).
17 November 2018
Dr. Veton Këpuska

8. 17 November 2018
Dr. Veton Këpuska

9. Introduction
In this chapter, the presence of multiple threads within a system will be considered.
Ways to control how the scheduler operates will be considered. In addition, the ability within DSP/BIOS to pace threads by time, rather than data availability, will be considered.
Special, CLK-PRD DSP/BIOS Module provides two methods of tracking time and hence provides a tool for controlling operations by time:
the high and low resolution clock managed by the CLK module and the system clock.
For this module the default configuration for the CLK module and system clock will be used.
17 November 2018
Dr. Veton Këpuska

10. Objectives
Describe the way BIOS can implement a time base 1
Setup a time base via the BIOS CLK module 2
Describe the results of invoking various BIOS CLK API 3
Set functions to run at a periodic rate via the PRD module 4
Describe how to implement delayed ‘one-shot’ functions 5
Describe how the scheduler can be managed via BIOS API 6
List various BIOS scheduler management API 7
Select and incorporate scheduler management API to obtain desired performance in a given system 8
17 November 2018
Dr. Veton Këpuska 2

11. 1 2 3 4 5 7 Module Topics Multi-Threaded Concepts Clock Manager CLK
Periodic Functions 3
Scheduler Management API
HWI Management API SWI Management API TSK Management API 4
Review 5
Lab 7
17 November 2018
Dr. Veton Këpuska 3

12. 1 2 3 4 5 7 Module Topics Multi-Threaded Concepts Clock Manager CLK
Periodic Functions 3
Scheduler Management API
HWI Management API
SWI Management API
TSK Management API 4
Review 5
Lab 7
17 November 2018
Dr. Veton Këpuska 3

13. Multi-Threading
17 November 2018
Dr. Veton Këpuska

14. Multi-Threading Can BIOS keep track of time for me?
Can time instead of data availability be used to launch threads?
17 November 2018
Dr. Veton Këpuska

15. 1 2 3 4 5 7 Module Topics Multi-Threaded Concepts Clock Manager CLK
Periodic Functions 3
Scheduler Management API
HWI Management API
SWI Management API
TSK Management API 4
Review 5
Lab 7
17 November 2018
Dr. Veton Këpuska 3

16. CLK – PRD Module of BIOS
The CLK module provides methods for gathering timing information and for invoking functions periodically.
The CLK module provides real-time clocks with functions to access the low-resolution and high-resolution times. These times can be used to measure the passage of time in conjunction with STS accumulator objects, as well as to add timestamp messages in event logs.
17 November 2018
Dr. Veton Këpuska

17. CLK – PRD Module of BIOS
DSP/BIOS provides the following timing methods:
Timer Counter. This DSP/BIOS counter changes at a relatively fast platform-specific rate. This counter is used only if the Clock Manager is enabled in the CLK Manager Properties.
Low-Resolution Time. This time is incremented when the timer counter reaches its target value. When this time is incremented, any functions defined for CLK objects are run.
High-Resolution Time. For some platforms, the timer counter is also used to determine the high-resolution time. For other platforms, a different timer is used for the high-resolution time.
17 November 2018
Dr. Veton Këpuska

18. CLK – PRD Module of BIOS
Periodic Rate. The PRD functions can be run at a multiple of the clock interrupt rate (the low-resolution rate) if you enable the "Use CLK Manager to Drive PRD" in the PRD Manager Properties.
System Clock. The PRD rate, in turn, can be used to run the system clock, which is used to measure TSK-related timeouts and ticks. If you set the "TSK Tick Driven By" in the TSK Manager Properties to "PRD", the system clock ticks at the specified multiple of the clock interrupt rate (the low-resolution rate).
17 November 2018
Dr. Veton Këpuska

19. Low and high resolution clock calculations
CLK Module
Example of the CLK module driven by a timer on the 'C6x’
Low and high resolution clock calculations
Interrupt
Low Resolution Clock + 1
System Clock =
Period
Period
Timer 0,1
High Resolution Clock +
Counter
17 November 2018
Dr. Veton Këpuska

20. CKL API
There are four main functions for accessing the clock information:
CLK_countspms() - Timer counts per millisecond
CLK_gethtime() - Get high resolution time
CLK_getltime() - Get low resolution time
CLK_getprd() - Get period register value
The first three functions return values of type LgUns and the last one returns a type Uns. None of them have any parameters.
17 November 2018
Dr. Veton Këpuska

21. BIOS Clock Services CLK API
CPU clock 
4 or 8
Timer
Timer ISR
Timer Interrupt
Low Rate Clock
High Rate Clock
Low Res Clock
Counter
System Tick
CLK Object(s) + x f
Period
CLK_countspms
CLK_getprd
CLK_getltime
CLK_gethtime
CLK API
Description
CLK_getltime
Get low-resolution time (32-bit value)
CLK_gethtime
Get high-resolution time (32-bit value)
CLK_getprd
Get period register value
CLK_countspms
Get number of hardware timer counts per millisecond
17 November 2018
Dr. Veton Këpuska

22. BIOS Clock Services CLK API
CLK abstracts details of HW timer to provide low-res time / system tick
Timer period is set and CLK objects specified in BIOS configuration
CLK can drive periodic objects directly, or at different rates as PRD SWI
CLK time values are often helpful in real-time analysis (next module)
17 November 2018
Dr. Veton Këpuska

23. CLK – PRD Module of BIOS
Many functions in DSP/BIOS have a timeout associated with them.
The system clock is used to determine the timeout. The system clock is configured by the periodic function monitor module (PRD module) and is driven by whatever object or function calls PRD_tick.
In the default settings the PRD_tick function is called by the CLK object: PRD_clock (find this by clicking on Scheduling->CLK in the configuration tool).
When the timer expires the hardware interrupt CLK_F_isr is run which then increments the low resolution clock and calls the functions for all the CLK objects (find this by clicking on Scheduling->HWI->HWI_INT14).
17 November 2018
Dr. Veton Këpuska

24. CLK – PRD Module of BIOS
Since PRD_clock is a CLK object it gets called which in turn calls the function PRD_tick. This increments the system clock.
The PRD_tick function then determines if the SWI PRD_swi should run. If it should run then it posts an SWI for PRD_swi.
17 November 2018
Dr. Veton Këpuska

25. Setup of CLK via Configuration Tool
Setup of the CLK Module
right click on CLK mgr
select “Properties”
define Low res clock rate via usecs/int
optionally, set other parameters as desired
17 November 2018
Dr. Veton Këpuska

26. Setup of CLK via Configuration Tool
Optional:
Making a new CLK object
right click on CLK mgr
select “Insert CLK”
type CLK name
right click on new CLK
select “Properties”
type function to run
17 November 2018
Dr. Veton Këpuska

27. Setup of CLK via Configuration Tool
All CLK objects are invoked each Lo Res tick – PRD fxns can run at different intervals – next...
17 November 2018
Dr. Veton Këpuska

28. 1 2 3 4 5 7 Module Topics Multi-Threaded Concepts Clock Manager CLK
Periodic Functions 3
Scheduler Management API
HWI Management API
SWI Management API
TSK Management API 4
Review 5
Lab 7
17 November 2018
Dr. Veton Këpuska 3

29. Periodic Functions: PRD
Can I have a number of functions, each invoked at a given periodic rate?
Can I invoke a function that will run once after a given time has passed?
17 November 2018
Dr. Veton Këpuska

30. DSP/BIOS Periodic Functions
A special SWI that provides preemptive scheduling for periodic functions
While SIO indicates data available and SEM indicates posting by other thread, when time is the gating event PRD is most ideal choice
Also useful for modeling interrupts to simulate peripherals (IO devices)
17 November 2018
Dr. Veton Këpuska

31. Periodic Events – PRD SWI
PRD Object
Period 4
Function
funcX()
Type
continuous
Arg0
Arg1
Timer ISR
PRD_swi
System
Tick
CLK Object(s)
PRD_obj
PRD_clock PRD_tick ...
PRD_obj
...
Period # of ticks before calling fxn
Function Function to execute
Type Continuous or One-shot
PRD_obj
17 November 2018
Dr. Veton Këpuska

32. Periodic Events – PRD SWI
PRD_tick() is invoked by PRD_clock by default (also TSK_tick)
PRD_tick() may be called by any desired user function as well
PRD_tick() launches the PRD_swi which
Scans the list of PRD_obj’s
Determines if the specified time for the given PRD_obj has elapsed
If so, the function associated with the PRD_obj is called
All PRD_obj functions must complete within ONE system (PRD) tick
Recommended: make PRD_swi highest priority SWI
If routines are short and tick is long - no problem
Long functions can be broken up with posts of other threads
17 November 2018
Dr. Veton Këpuska

33. Setup of PRD via Configuration Tool
Creating a PRD
right click on PRD mgr
select “Insert PRD”
type PRD name
right click on new PRD
select “Properties”
indicate desired
period (ticks)
mode
function
arguments
17 November 2018
Dr. Veton Këpuska

34. Setup of PRD via Configuration Tool
A PRD can directly launch a regular SWI by specifying:
function: _SWI_post
arg0: _mySWI
allowing control of priority, and meeting requirement for all PRDs to complete before the next PRD tick
17 November 2018
Dr. Veton Këpuska

35. TCONF Setup of PRD Module & Object
PRD.OBJMEMSEG = prog.get("myMEM"); where to locate PRD Objects PRD.USECLK = "true"; CLK MOD will feed PRD PRD.MICROSECONDS = ; uSecs/tick – skip if using CLK var myPrd = PRD.create(“myPrd"); create a PRD Object myPrd.period = 1024; # of ticks between calls to PRD Obj * myPrd.mode = "continuous"; type – continuous or “one-shot” myPrd.fxn = prog.extern(“_myFxn"); function PRD Obj will run myPrd.arg0 = 0; user arguments - optional myPrd.arg1 = 0;
* Underlying interrupt rate is largest binary number divisible into period value, so for lowest overhead, pick a binary number when possible
17 November 2018
Dr. Veton Këpuska

36. One-shot Periodic Functions
Allows delayed execution of a function by n system ticks
PRD_start()invokes each iteration of the one-shot function
PRD_stop()can be used to abort a one-shot prior to timeout
Example of use: software watchdog function
PRD Object X
Period 4
Function
funcX()
Type
1 shot
Arg0
Arg1
Low-res clock (incremented by system tick)
PRD_start()
funcX()
17 November 2018
Dr. Veton Këpuska

37. PRD API Review
PRD API
Description
PRD_tick
Advance tick counter, dispatch periodic functions
PRD_start
Arm a periodic function for onetime execution
PRD_stop
Stop a periodic function from execution
PRD_getticks
Get the current tick counter
Tick counter can be manually incremented by the user with PRD_tick()
One-shot periodic functions are managed with PRD_start() & PRD_stop()
Inspection of tick count is possible with PRD_getticks()
Continuous periodic functions are set up via the BIOS configuration tool and are generally not managed at run-time via BIOS API
17 November 2018
Dr. Veton Këpuska

38. Scheduler Management API
Multi-Threaded Concepts 1
Clock Manager CLK 2
Periodic Functions 3
Scheduler Management API
HWI Management API, SWI Management API &
TSK Management API 4
Review 5
Lab 7
17 November 2018
Dr. Veton Këpuska 3

39. Scheduler Control API Scheduler Control API is designed to control:
HWI & IDL processes
SWI processes, and
TSK
Is it possible to alter the behavior of the BIOS scheduler when the need arises?
17 November 2018
Dr. Veton Këpuska

40. Scheduler Management API
Generally, threads are automatically managed by BIOS according to the priorities of each thread
Sometimes, however, it is desirable to alter the normal BIOS scheduler operation, for example:
When deadlines are approaching a thread can temporarily be given higher priority or even exclusive use of the processor
When multiple threads share a resource, priorities can be modified to avoid higher priority threads interrupting critical sections of lower priority threads
To implement time slicing amongst equal priority threads (equal threads are normally “FIFO” serviced)
To allow TSKS to ‘sleep’ for a time
17 November 2018
Dr. Veton Këpuska

41. Scheduler Management API
In these cases, API can be invoked to alter the behavior of the scheduler with respect to HWI, SWI, and TSK as required
17 November 2018
Dr. Veton Këpuska

42. Scheduler Management API
Digital Systems: Hardware Organization and Design
11/17/2018
Scheduler Management API
HWI & IDL i
SWI ii
TSK
iii
17 November 2018
Dr. Veton Këpuska 3
Architecture of a Respresentative 32 Bit Processor

43. HWI & IDL Scheduler Control
What kind of control can I have on how hardware interrupts and the idle thread are scheduled by BIOS?
HWI_disable() Creates a period where no asynchronous events may occur
HWI_restore() does not necessarily enable interrupts, but instead asserts to state prior to HWI_disable()
17 November 2018
Dr. Veton Këpuska

44. HWI_disable and HWI_restore API
oldCSR = HWI_disable(); // “critical section” // scheduler inhibited ... HWI_restore(oldCSR);
Interrupts that come in during the period where HWI_disable() is being executed will be held off until HWI is re-enabled (if a given interrupt occurs more than once in this period, the additional events will be lost)
17 November 2018
Dr. Veton Këpuska

45. HWI and IDL Scheduler API
HWI, IDL API
Description
HWI_enable
Globally enable hardware interrupts
HWI_disable
Globally disable hardware interrupts
HWI_restore
Restore global interrupt enable state
IDL_run
Make one pass through idle functions*
17 November 2018
Dr. Veton Këpuska

46. Interrupt Management Intrinsic
Faster than the BIOS API
They are not commonly used
Not callable by HWI or SWI
Unsigned int _disable_interrupts();
Unsigned int _enable_interrupts();
Void _restore_interrupts(unsigned int);
17 November 2018
Dr. Veton Këpuska

47. Scheduler Management API
Digital Systems: Hardware Organization and Design
11/17/2018
Scheduler Management API
HWI & IDL i
SWI ii
TSK
iii
17 November 2018
Dr. Veton Këpuska 3
Architecture of a Respresentative 32 Bit Processor

48. SWI Scheduling
What kind of control can I have on how software interrupts are scheduled by BIOS?
Similar to HWI_disable/HWI_restore
SWI_disable – All interrupts that come in during the period where SWI_disable is being executed will be held off until SWI is re-enabled.
Concludes with SWI_enable (not “SWI_restore”)
Acts on SWI scheduling only – HWI continue unchanged
Nestable - number of levels managed by BIOS
17 November 2018
Dr. Veton Këpuska

49. Disabling & Enabling Software Interrupts
SWI_disable();
// “critical section” // SWI scheduler inhibited ...
SWI_enable();
17 November 2018
Dr. Veton Këpuska

50. Temporary Elevation of SWI Priority
SWI_raisepri() can be used to raise the SWI priority.
SWI_raisepri() cannot lower priority (actually disables lower priority levels)
Priority returns to the original value when the SWI exits
Original Priority (“origPrio”) should be a local variable
Priority values are bit positions, not integer numbers (eg: priority 7 would be b)
To elevate a SWI above one (or several other) SWI, use in conjunction with SWI_getpri, as per the example below:
17 November 2018
Dr. Veton Këpuska

51. Temporary Elevation of SWI Priority
origPrio = SWI_raisepri(1<<7); // critical section // lower prio SWIs inhibited ... SWI_restorepri(origPrio);
For Priority level “X” select 1<<X as the argument to raisepri
Example of using SWI_getpri():
origPrio = SWI_raisepri(SWI_getpri(&swiX)|SWI_getpri(&swiY)); // critical section // SWI scheduler inhibited ... SWI_restorepri(origPrio);
17 November 2018
Dr. Veton Këpuska

52. SWI Scheduler API SWI API Description SWI_disable
Disable software interrupts
SWI_enable
Enable software interrupts
SWI_getpri
Return an SWI’s priority mask
SWI_raisepri
Temporarily raise an SWI’s priority
SWI_restorepri
Restore an SWI’s priority to object value
SWI_self
Return address of SWI’s object
17 November 2018
Dr. Veton Këpuska

53. Scheduler Management API
Digital Systems: Hardware Organization and Design
11/17/2018
Scheduler Management API
HWI & IDL i
SWI ii
TSK
iii
17 November 2018
Dr. Veton Këpuska 3
Architecture of a Respresentative 32 Bit Processor

54. TSK Scheduling and Control
What kind of control can I have on how tasks are scheduled by BIOS?
TSK_disable and TSK_enable
Similar to SWI_disable/SWI_enable
Acts on TSK scheduling only – SWI & HWI continue unchanged
Nestable - number of levels managed by BIOS
17 November 2018
Dr. Veton Këpuska

55. Disabling & Enabling Task Scheduling
TSK_disable();
// “critical section” // TSK scheduler inhibited ...
TSK_enable();
17 November 2018
Dr. Veton Këpuska

56. Modification of a Task’s Priority
TSK_setpri() can raise or lower priority
Return argument of TSK_setpri() is previous priority
New priority remains until set again or TSK is deleted and re-created
TSK priority is an integer value: 1 to 15 (unlike SWI, using binary weighted numbers)
To suspend a TSK, set its priority to negative one (-1)
Suspended TSK not part of BIOS TSK scheduling queue
TSK can be activated at any time (by some other thread) via TSK_setpri()
Handy option for statically created TSKs that don’t need to run right away
A TSK can be suspended at any time under BIOS, by itself or another thread
17 November 2018
Dr. Veton Këpuska

57. Modification of a Task’s Priority
Example
origPrio = TSK_setpri(TSK_self(),7); // critical section // TSK priority increased or reduced ... TSK_setpri(TSK_self(),origPrio);
17 November 2018
Dr. Veton Këpuska

58. TSK_yield : Time Slicing
TSK_yield() instructs the BIOS scheduler to move the current TSK to the end of the priority queue
If another TSK of equal priority is ready, it will then be the active TSK
This API can be invoked at any time by the active TSK or any SWI/HWI
If a PRD calls TSK_yield, time slicing amongst equal priority TSKs is achieved
17 November 2018
Dr. Veton Këpuska

59. TSK_yield : Time Slicing
TSK_A
Running
TSK_B
Must be
Equal
Priority!
Ready
TSK_C
TSK_D
Time
17 November 2018
Dr. Veton Këpuska

60. TSK_sleep and TSK_tick
TSK_sleep(Uns sleeptime)
Blocks execution of current TSK for n TSK ticks
TSK_tick()
Similar to PRD_tick for PRD SWIs
Advances the task alarm tick by one count
Default - called from PRD_clock (system tick)
If ‘ticks’ are events and not time, TSK_tick can be called from any thread
TSK_itick() is for use inside ISRs w/o dispatcher
17 November 2018
Dr. Veton Këpuska

61. Task Control Block Model
BIOS Startup
READY
TSK_yield()
TSK_setpri()
TSK_tick()
SEM_post()
RUNNING
TERMINATED
BLOCKED
TSK_exit()
TSK_sleep()
SEM_pend()
17 November 2018
Dr. Veton Këpuska

62. TSK Scheduler API TSK API Description TSK_disable
Disable DSP/BIOS task scheduler
TSK_enable
Enable DSP/BIOS task scheduler
TSK_self
Returns address of task object
TSK_getpri
Get task priority
TSK_setpri
Set a tasks execution priority
TSK_yield
Yield processor to equal priority task
TSK_sleep
Delay execution of the current task
TSK_tick
Advance system alarm clock
TSK_itick
Advance system alarm clock (ISR)
TSK_time
Return current value of system clock
17 November 2018
Dr. Veton Këpuska

63. 1 2 3 4 5 7 Module Topics Multi-Threaded Concepts Clock Manager CLK
Periodic Functions 3
Scheduler Management API 4
Review 5
Lab 7
17 November 2018
Dr. Veton Këpuska 3

64. Questions?
17 November 2018
Dr. Veton Këpuska

65. 1 2 3 4 5 7 Module Topics Multi-Threaded Concepts Clock Manager CLK
Periodic Functions 3
Scheduler Management API 4
Review 5
Lab 7
17 November 2018
Dr. Veton Këpuska 3

66. Lab Adding 2nd thread CLK/PRD API to launch dummy thread
dummy load
LED blinker
CLK/PRD API to launch dummy thread
Use some sched mgmt API to influence performance
17 November 2018
Dr. Veton Këpuska

67. Lab 7a: Multiple Threads
C:\dvsdk_1_01_00_15\psp_1_00_02_00
BIOS provided
Audio In (48 KHz)
CLK – 100mS
ADC AIC33
McBSP DRR
dioCodec
IOM
udevCodec
DAC AIC33
McBSP DXR
SIO
Audio Out (48 KHz)
PRD SWI
tskProcBuf
procBuf
while()
SIO_reclaim(&sioIn)
for (i =0, i<HIST; i ++)
pIn[i-HIST]=pPriorIn[2*BUF-HIST];
if( sw0 == 1 )
FIR(in[pIn-HIST],out[pOut])
else {pOut[i]=pIn[i]}
fxnLoad()
BIOS\Labs\Algos
FIR.c
FIR Code
fxnLoad()
read DIP sw’s
call asm fn: load
(load amt spec’d
by sw values)
coeffs.c
Coefficients
00 none
10 low
01 hi
11 >100%
DIP Sw’s: 3 2
17 November 2018
Dr. Veton Këpuska

68. Lab 7a: Multiple Threads
Begin with Lab 6 solution
Add Load.c and NopLoop.asm (Algos dir) to project
In TCF file: set up CLK rate, create PRD SWI running at 100mSec rate, calling fxnLoad
Build, load, run; test audio w. range of DIP cases
17 November 2018
Dr. Veton Këpuska

69. Lab7b: Multiple Threads - Improved
C:\dvsdk_1_01_00_15\psp_1_00_02_00
BIOS provided
Audio In (48 KHz)
CLK – 100mS
ADC AIC33
McBSP DRR
dioCodec
IOM
PRD SWI
udevCodec
DAC AIC33
McBSP DXR
SIO
Function: _SEM_post
Arg0: _mySem
Audio Out (48 KHz)
TSK
tskProcBuf
procBuf
while()
SIO_reclaim(&sioIn)
for (i =0, i<HIST; i ++)
pIn[i-HIST]=pPriorIn[2*BUF-HIST];
if( sw0 == 1 )
FIR(in[pIn-HIST],out[pOut])
else {pOut[i]=pIn[i]}
tskLoad()
SEM_pend(mySem)
callfxnLoad
BIOS\Labs\Algos
FIR.c
FIR Code
fxnLoad()
read DIP sw’s
call asm fn: load
(load amt spec’d
by sw values)
coeffs.c
Coefficients
00 none
10 low
01 hi
11 >100%
DIP Sw’s: 3 2
17 November 2018
Dr. Veton Këpuska

70. Lab7b: Multiple Threads - Improved
Have PRD SWI post SEM
Put call to fxnLoad in TSK while loop
Add SEM pend to TSK while loop
Create SEM for above signalling
Build, load, run; test audio w. range of DIP cases
17 November 2018
Dr. Veton Këpuska

71. Load.c
void fxnLoad(void) { short i; unsigned char mask, dips; static Bool blink = 0; EVMDM6437_I2C_read( I2C_GPIO_GROUP_0, &dips, 1 ); if(hw_sw0 == (dips>>4&1)) {sw0 = hw_sw0 = !(dips>>4&1);} if(hw_sw1 == (dips>>5&1)) {sw1 = hw_sw1 = !(dips>>5&1);} if( ( hw_sw2==(dips>>6&1)) | (hw_sw3== (dips>>7&1)) ){ sw2 = hw_sw2 = !(dips>>6&1); sw3 = hw_sw3 = !(dips>>7&1); }
17 November 2018
Dr. Veton Këpuska

72. Load.c
switch(2*sw2+sw3){ case (3) : for (i=0; i< 7; i++){load(5000);} case (2) : for (i=0; i<12; i++){load(5000);} case (1) : load(5500); case (0) : load( 100); } blink^=1; mask = (char)( 0x0F^((1^blink)<<2*sw2+sw3) ); EVMDM6437_I2C_write( I2C_GPIO_GROUP_1, &mask, 1 ); IDL_run(); }
17 November 2018
Dr. Veton Këpuska

73. TI BIOS CLK-PRD
END
17 November 2018
Dr. Veton Këpuska