Developing a bicycle speed-o-meter Midterm Review NOTE after the midterm, Dr. Krisnamurphy will be tackling this design with you on the 68K processor so you can get practice using a different processor

General Project concept Blackfin Programmable Flag (PF) Input Magnetic Sensor Signal Motorola Parallel Interface Timer (PIT) Input High speed clock signal 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Main function concept ulong DetermineSpeed(ulong wheelDiameter, ulong clockFrequency) #define ulong unsigned long int; extern “C” ulong CountClockASM(const int); // Assembly code interface extern “C” ulong CalculateSpeedASM(ulong, ulong, ulong); extern “C” void SetupInterface(void); ulong DetermineSpeed(ulong wheelDiameter, ulong clockFrequency) { // Get to known position on magnetic sensor signal unsigned long discard_count; unsigned long count_high, count_low; SetupInterface( ); discard_count = CountClockASM(while_MagneticSensorHigh); // Not ready yet discard_count = CountClockASM(while_MagneticSensorLow); // Not ready yet count_high = CountClockASM(while_MagneticSensorHigh); count_low = CountClockASM(while_MagneticSensorLow); return CalculateSpeedASM(count_high + count_low, wheelDiameter, clockFrequency); } 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

How many clock ticks pass while magnetic sensor value stays a certain way? extern “C” ulong CountClockASM(const int); // Assembly code interface extern “C” void SetupInterface(void); extern “C” ulong CalculateSpeedASM(ulong, ulong, ulong); ulong CountClockASM(const int high_low) { // Either a high magnetic sensor value (1) // or low sensor value (0) needs measuring ulong clock_count = 0; while (magnetic_sensor = = high_low) { // if signal is unchanged from start // Must count just one clock signal low-to-high transition while (clock_signal = = high) /* wait */; while (clock_signal = = low) /* wait */; // Changes on low-to-high edge clock_count++; } return clock_count; } // Must assume that clock-signal is MUCH faster than sensor signal 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

What we need to know How can you pass parameters between “C/C++” and assembly code functions? How can you return a parameter from assembly code functions? What registers are available on the processor? How do you set up the interface between the processor and the real world Many signals are coming into processor, how do you separate (mask off) the signals you want from those you don’t? What are the basic operations for accessing memory? What are the basic ALU operations for this processor? 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Programming model Blackfin Data Registers R0, R1 …. R7 Address Registers Pointer Registers P0, P1 … P5 Frame Buffer FP Stack Pointer SP Special DSP I0-I3, B0-B3, M0-M3, L0-L3 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Syntax examples Blackfin Register to Register Move reg1  reg 2 32 bit operations R1 = R2; (1 cycle @ 500 MHz) Register to Register Move reg1  reg 2 16 bit operations R1.L = R2.L; and also R1.H = R2.L; Register to Register Move reg1  reg 2 8 bit operations Here is some new syntax that convert 8-bit values into 32 bit values R1 = R2.B (X); R1.L = R2.B (Z); R1 = R2.B(X); 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Syntax examples Blackfin Register to Register ADD reg1  reg 2 + reg3 32 bit operations R1 = R2 + R3; (1 cycle @ 500 MHz) Register to Register Move reg1  reg 2 + reg3 16 bit operations R1.L = R2.L + R3.L (NS); (1 cycle @ 500 MHz) Also R1 = R2 +|- R3; Means R1.L = R2.L – R3.L; and R1.H = R2.H + R3.H; Register to Register Move reg1  reg 2 + reg3 8 bit operations R1.L = R2.B (X); R0.L = R3.B (X); R1.L = R1.L + R0.L (NS); ( > 3 cycles @ 500 MHz) 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

32-bit Memory Move operations Blackfin Value at memory location 1 placed at memory location 2 P0.H = hi(_MEM1); P0.L = lo(_MEM1); P1.H = hi(_MEM2); P1.L = lo(_MEM2); R0 = [P0]; [P1] = R0; > 6 cycles Multiple moves P1.H = hi(_MEM2); P1.L = lo(_MEM2); R0 = [P0++]; [P1++] = R0; R0 = [P0++]; 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

16-bit Memory Move operations Blackfin Value at memory location 1 placed at memory location 2 P0.H = hi(_MEM1); P0.L = lo(_MEM1); P1.H = hi(_MEM2); P1.L = lo(_MEM2); R0 =W [P0]; W[P1] = R0; > 6 cycles Multiple moves P1.H = hi(_MEM2); P1.L = lo(_MEM2); R0 = W[P0++] (X); W [P1++] = R0; R0 = W[P0++] (X); W[P1++] = R0; R0 =W [P0++] (X); 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Memory Move operations Blackfin Multiple moves of registers [- - SP] = (R7:5, P5:3); Combination of memory moves and ALU operations Can also do parallel read and write operations together with math operations Syntax looks like this R1 = R2 | | R3 = [P0++] | | [I1++] = R4; Not all operations can be made parallel 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

If – then – else constructs Signed tests Blackfin Set the condition code register CC = D1 == D0; CC = D1 < D0; CC = D1 <= D0; Conditional jump IF CC JUMP NEXT_INSTR IF !CC JUMP NEXT_INSTR 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

If – then – else constructs Un-signed tests Blackfin Set the condition code register CC = D1 == D0 (IU); CC = D1 < D0 (IU); CC = D1 <= D0 (IU); Conditional jump IF CC JUMP NEXT_INSTR IF !CC JUMP NEXT_INSTR 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Example if-then-else code C++ example Blackfin IF (A > B) C = D; ELSE C = E; Set A, B, C, D, E to registers R0, R1, .. R4 CC = R1 < R0; IF !CC JUMP ELSE; R2 = R3; JUMP END_IF; ELSE: R2 = R4; END_IF: CC = R1 < R0; IF CC R2 = R3; IF !CC R2 = R4; 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Example loop code -- software loop C++ example Blackfin sum = 0; for (loop = 0; loop < 6; loop++) sum = sum + loop; Set R0 = sum , R1 = loop R0 = 0; R1 = 0; R2 = 6; LOOP: CC = R2 <= R1; IF !CC JUMP PAST_LOOP; R0 = R0 + R1; R1 += 1; JUMP LOOP PAST_LOOP: 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Example loop code -- Hardware loop C++ example Blackfin sum = 0; for (loop = 0; loop < 6; loop++) sum = sum + loop; Set R0 = sum , R1 = loop R0 = 0; R1 = 0; P1 = 6; LSETUP(LSTART, LEND) LC1 = P1; LSTART: R0 = R0 + R1; LEND: R1 += 1; PAST_LOOP: OUTSIDE THE LOOP Has a capability of 2 hardware (high-speed, zero overhead) loop 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Reminder of what we were trying to do General Project concept Blackfin Programmable Flag (PF) Input Magnetic Sensor Signal Motorola Parallel Interface Timer (PIT) Input High speed clock signal 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Required Assembly Language extern “C” ulong CountClockASM(const int); // Assembly code interface extern “C” void SetupInterface(void); extern “C” ulong CalculateSpeedASM(ulong, ulong, ulong); ulong CountClockASM(const int high_low) { ulong clock_count = 0; while (magnetic_sensor = = high_low) { // if signal is unchanged from start // Must count just one clock signal low-to-high transition while (clock_signal = = high) /* wait */; while (clock_signal = = low) /* wait */; // Changes on low-to-high edge clock_count++; } return clock_count; 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Hardware test – wait while magnetic signal is “high” Blackfin Magnetic Signal Bit 10 of FIO_FLAG_D register of PF interface while (mag_signal == HIGH) /* wait */ ; #define MASK 0x400 P0.H = hi(FIO_FLAG_D); P0.L = lo(FIO_FLAG_D); R1 = MASK; WHILE: R0 = W[P0] (Z); R0 = R0 & R1; CC = R0 == R1; IF CC JUMP WHILE (BP); 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Required BF533 Assembly Language _CountClockASM: R0 contains the INPAR R1 = 0; P0.H = hi(FIO_FLAG_D); P0.L = lo(FIO_FLAG_D); WHILE: R2 = W[P0] (Z); R3 = MASKMAG; // SLOW Magnetic Signal on bit 10 R2 = R2 & R3; CC = R2 == R0; IF !CC JUMP ENDWHILE; R3 = MASKCLK; // FAST Clock Signal on bit 11 HIGH: R2 = W[P0] (Z); CC = R2 == R3 IF CC JUMP HIGH (BP); LOW : R2 = W[P0] (Z); CC = R2 < R3 IF CC JUMP LOW (BP); R1 += 1; JUMP WHILE END_WHILE: R0 = R1; RTS ulong CountClockASM(const int high_low) { ulong clock_count = 0; while (magnetic_sensor = = high_low) { // if signal is unchanged from start // Must count just one clock signal // low-to-high transition while (clock_signal = = high) /* wait */; while (clock_signal = = low) /* wait */; // Changes on low-to-high edge clock_count++; } return clock_count; 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Subroutine / Function calls Blackfin extern “C” int FooASM(int, int, int) C = FooASM(1,2,3) .extern _FooASM LINK 20; [SP + 16] = R4; R0 = 1; R1 = 2; R2 = 3; CALL _FooASM; R4 = R0; .. Other code R4 = [SP + 16]; UNLINK; RTS; 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Code conventions for subroutines / functions Blackfin -- VisualDSP Volatile registers Destroyed after CALL R0, R1, R2, R3 P0, P1, P2 Non-volatile registers MUST BE UNCHANGED after CALL to a subroutine R4, R5, R6, R7 P3, P4, P5, FP, SP Subroutine return value is passed in R0 Subroutine OUTPARS OUTPAR1  R0 OUTPAR2  R1 OUTPAR3  R2 OUTPAR4  [SP + 12] 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Main function concept ulong DetermineSpeed(ulong wheelDiameter, ulong clockFrequency) #define ulong unsigned long int; extern “C” ulong CountClockASM(const int); // Assembly code interface extern “C” ulong CalculateSpeedASM(ulong, ulong, ulong); extern “C” void SetupInterface(void); ulong DetermineSpeed(ulong wheelDiameter, ulong clockFrequency) { // Get to known position on magnetic sensor signal unsigned long discard_count; unsigned long count_high, count_low; SetupInterface( ); discard_count = CountClockASM(while_MagneticSensorHigh); discard_count = CountClockASM(while_MagneticSensorLow); count_high = CountClockASM(while_MagneticSensorHigh); count_low = CountClockASM(while_MagneticSensorLow); return CalculateSpeedASM(count_high + count_low, wheelDiameter, clockFrequency); } 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Main Blackfin function concept _DetermineSpeed: LINK 20 [FP + 8] = R0; [FP + 12] = R1; // Save INPARS [SP + 16] = R4; CALL _SetupInterface; R0 = MASKMAG; CALL _CountClockASM; R0 = 0; CALL _CountClockASM R4 = R0; // count_high R0 = R0 + R4; // high + low. R1 = [FP + 8]; // old INPAR1 R2 = [FP + 12]; // old INPAR2 CALL _CalculateSpeedASM // Return in R0 [SP + 16] = R4; UNLINK RTS ulong DetermineSpeed(ulong wheelDiameter, ulong clockFrequency) { // Get to known position on magnetic sensor signal unsigned long discard_count; unsigned long count_high, count_low; SetupInterface( ); discard_count = CountClockASM(while_MagneticSensorHigh); discard_count = CountClockASM(while_MagneticSensorLow); count_high = CountClockASM(while_MagneticSensorHigh); count_low = CountClockASM(while_MagneticSensorLow); return CalculateSpeedASM(count_high + count_low, wheelDiameter, clockFrequency); } 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

extern “C” void SetupInterface(void); Blackfin Direction register 0 = input, 1 = output FIO_DIR 16-bits Interrupt control FIO_MASKA_D on any bit Enable input (Power save issue) FIO_INEN on any bit Polarity FIO_POLAR on any bit Edge / Level sensitivity FIO_EDGE FIO_BOTH on any bit Magnetic signal Clock signal Bit 10 MASKMAG 0x200 Bit 11 MASKCLK 0x400 4/14/2019 Motorola Blackfin Comparison Part 2 , Copyright M. Smith, ECE, University of Calgary, Canada

extern “C” void SetupInterface(void); SPECIFICS Blackfin Magnetic signal Clock signal Bit 10 MASKMAG 0x200 Bit 11 MASKCLK 0x400 Direction register 0 = input, 1 = output R0  FIO_DIR MASK OFF BITS 10, 11 FIO_DIR  R0 Interrupt control R0  FIO_MASKA_D MASK OFF BITS 10, 11 FIO_MASKA_D  R0 Enable input (Power save issue) R0  FIO_INEN OR BITS 10, 11 FIO_INEN  R0 Polarity R0  FIO_POLAR MASK OFF BITS 10, 11 FIO_POLAR  R0 Edge / Level sensitivity FIO_EDGE FIO_BOTH MASK OFF BITS 10, 11 4/14/2019 Motorola Blackfin Comparison Part 2 , Copyright M. Smith, ECE, University of Calgary, Canada

In class exercise – Write Blackfin code for extern “C” void SetupInterface(void); 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada

Information taken from Analog Devices On-line Manuals with permission http://www.analog.com/processors/resources/technicalLibrary/manuals/ Information furnished by Analog Devices is believed to be accurate and reliable. However, Analog Devices assumes no responsibility for its use or for any infringement of any patent other rights of any third party which may result from its use. No license is granted by implication or otherwise under any patent or patent right of Analog Devices. Copyright  Analog Devices, Inc. All rights reserved. 4/14/2019 Motorola Blackfin Comparison Part 1 , Copyright M. Smith, ECE, University of Calgary, Canada