1. Developing a bicycle speed-o-meter Part 2
A comparison between the Analog Devices ADSP-BF533 (Blackfin) and Motorola MC68332

2. General Project concept
Blackfin Programmable
Flag (PF) Input
Magnetic Sensor Signal
Motorola Parallel Interface
Timer (PIT) Input
High speed clock signal
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

3. 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); }
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

4. 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;
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

5. Programming model MC68332 Blackfin Data Registers D0, D1 …. D7
R0, R1 …. R7
Address Registers
A0, A1 …. A6
Pointer Registers
P0, P1 … P5
Frame Buffer
Use A4 or A6 FP
Stack Pointer
SP (A7) SP
Special DSP
I0-I3, B0-B3, M0-M3, L0-L3
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

6. Register to Register Move reg1  reg 2 32 bit operations
Syntax examples
MC68332
Blackfin
Register to Register Move reg1  reg 2 32 bit operations
MOVE.L D2, D1
R1 = R2;
Memory Moves
MOVE.L #MEM1, A0 MOVE.L #MEM2, A1
MOVE.B (A0), (A1)
(8-bits)
P0.H = hi(MEM1); P0.L = lo(MEM1);
P1.H = hi(MEM2); P1.L = lo(MEM2); R0 =W [P0];
W[P1] = R0; bits
Set the condition code register
CMP.L D0, D1
CC = D1 == D0; CC = D1 < D0; CC = D1 <= D0;
Conditional jump
BEQ NEXT_INSTR (D1 == D0) BLT NEXT_INSTR (D1 < D0) BLE NEXT_INSTR (D1 <= D0)
IF CC JUMP NEXT_INSTR
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

7. Example loop code -- software loop
C++ example
Motorola
Blackfin
sum = 0;
for (loop = 0; loop < 6; loop++) sum = sum + loop;
Set D0 = sum , D1 = loop MOVE.L #0, D MOVE.L #0, D1
LOOP: CMP.L #6, D BGE PAST_LOOP ADD.L D1, D0
ADD.L #1, D BRA LOOP
PAST_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
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

8. Hardware test – wait while magnetic signal is “high”
Motorola
Blackfin
Magnetic Signal
Bit 1 of PADR register of PI/T interface
Bit 10 of FIO_FLAG_D register of PF interface
while (mag_signal == HIGH)
/* wait */ ;
MASK EQU 0x1
MOVE.L #PITBASE, A0
WHILE:
MOVE.B PADR(A0), D AND.B #MASK, D CMP.B #MASK, D BEQ WHILE
#define MASK 0x400
P0.H = hi(FIO_FLAG_D);
P0.L = lo(FIO_FLAG_D); R1 = MASK;
R0 = W[P0] (Z); R0 = R0 & R1; CC = R0 == R1; IF CC JUMP WHILE (BP);
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

9. Required 68K Assembly Language
_CountClockASM:
MOVEA.L #0, A1 // Use as counter MOVEA.L #PITBASE, A MOVE.L 4(SP), D0
WHILE:
MOVE.B PADR(A0), D AND.B #MASKMAG, D CMP.B D0, D1
BNE END_WHILE
HIGH: MOVE.B PADR(A0), D AND.B #MASKCLK, D BNE HIGH
LOW: MOVE.B PADR(A0), D AND.B #MASKCLK, D BEQ LOW
ADDA.L #1, A1
BRA WHILE
END_WHILE: MOVE.L A1, D0
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;
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

10. 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;
R2 = R2 & R3;
CC = R2 == R0;
IF !CC JUMP ENDWHILE;
R3 = MASKCLK;
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;
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

11. Compare 68K and Blackfin 4/25/2019
_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;
R2 = R2 & R3;
CC = R2 == R0;
IF !CC JUMP ENDWHILE;
R3 = MASKCLK;
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
_CountClockASM:
MOVEA.L #0, A1 // Use as counter MOVEA.L #PITBASE, A MOVE.L 4(SP), D0
WHILE:
MOVE.B PADR(A0), D AND.B #MASKMAG, D CMP.B D0, D1
BNE END_WHILE
HIGH: MOVE.B PADR(A0), D AND.B #MASKCLK, D BNE HIGH
LOW: MOVE.B PADR(A0), D AND.B #MASKCLK, D BEQ LOW
ADDA.L #1, A1
BRA WHILE
END_WHILE: MOVE.L A1, D0
RTS
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

12. Subroutine / Function calls
Motorola
Blackfin
extern “C” int FooASM(int, int, int)
C = FooASM(1,2,3)
.IMPORT _FooASM
FP EQU A6
LINK FP, -16
MOVE.L D4, 12(SP)
MOVE.L #1, 0(SP) MOVE.L #2, 4(SP)
MOVE.L #3, 8(SP)
JSR _FooASM
MOVE.L D0, D4
.. Other code
MOVE.L 12(SP), D4 UNLINK
RTS
.extern _FooASM
LINK 20;
[SP + 16] = R4;
R0 = 1;
R1 = 2;
R2 = 3;
CALL _FooASM;
R4 = R0;
R4 = [SP + 16];
UNLINK;
RTS;
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

13. Code conventions for subroutines / functions
Motorola -- SDS
Blackfin -- VisualDSP
Volatile registers
D0, D1
A0, A1
R0, R1, R2, R3 P0, P1, P2
Non-volatile registers
D2, D2, D4, D5, D6, D7 A2, A3, A4, A5, A6, A7
R4, R5, R6, R7
P3, P4, P5, FP, SP
Subroutine return value is passed in D0 R0
Subroutine OUTPARS
OUTPAR1  0(SP)
OUTPAR2  4(SP)
OUTPAR3  8(SP)
OUTPAR4  12(SP)
OUTPAR1  R0
OUTPAR2  R1
OUTPAR3  R2
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

14. Main 68K function concept
_DetermineSpeed: LINK A6, -16
MOVE.L D4, 12(SP)
JSR _SetupInterface
MOVE.L #MASKMAG, 0(SP) JSR _CountClockASM
MOVE.L #0, 0(SP) JSR _CountClockASM
MOVE.L #MASKMAG, 0(SP) JSR _CountClockASM MOVE.L D0, D4 ; count_high
MOVE.L #0, 0(SP) JSR _CountClockASM
ADD.L D0, D ; high + low.
MOVE.L D4, 0(SP)
MOVE.L 8(FP), 4(SP)
MOVE.L 12(FP), 8(SP)
JSR _CalculateSpeedASM ; Return in D0
MOVE.L 12(SP), D4
UNLINK A6
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); }
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

15. 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); }
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

16. Compare 68K and Blackfin _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
_DetermineSpeed: LINK A6, -16
MOVE.L D4, 12(SP)
JSR _SetupInterface
MOVE.L #MASKMAG, 0(SP) JSR _CountClockASM
MOVE.L #0, 0(SP) JSR _CountClockASM
MOVE.L #MASKMAG, 0(SP) JSR _CountClockASM MOVE.L D0, D4 ; count_high
MOVE.L #0, 0(SP) JSR _CountClockASM
ADD.L D0, D ; high + low.
MOVE.L D4, 0(SP)
MOVE.L 8(FP), 4(SP)
MOVE.L 12(FP), 8(SP)
JSR _CalculateSpeedASM ; Return in D0
MOVE.L 12(SP), D4
UNLINK A6
RTS
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

17. extern “C” void SetupInterface(void);
Motorola
Blackfin
Direction register
0 = input, 1 = output
PADDR bits
FIO_DIR bits
Interrupt control
bits in PACR, PGCR control H1, H2
FIO_MASKA_D on any bit
Enable input (Power save issue)
FIO_INEN on any bit
Polarity
bits in PGCR
control H1, H2
FIO_POLAR on any bit
Edge / Level sensitivity
FIO_EDGE FIO_BOTH on any bit
Magnetic signal Clock signal
Bit 0 MASKMAG 0x1 Bit 1 MASKCLK 0x2
Bit 10 MASKMAG 0x200 Bit 11 MASKCLK 0x400
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

18. extern “C” void SetupInterface(void); SPECIFICS
Motorola
Blackfin
Magnetic signal Clock signal
Bit 0 MASKMAG 0x1 Bit 1 MASKCLK 0x2
Bit 10 MASKMAG 0x200 Bit 11 MASKCLK 0x400
Direction register
0 = input, 1 = output
D0  PADDR MASK OFF BITS 1, PADDR  D0
R0  FIO_DIR MASK OFF BITS 10, FIO_DIR  R0
Interrupt control
bits in PACR, PGCR control H1, H2
R0  FIO_MASKA_D MASK OFF BITS 10, FIO_MASKA_D  R0
Enable input (Power save issue)
R0  FIO_INEN OR BITS 10, FIO_INEN  R0
Polarity
bits in PGCR
control H1, H2
R0  FIO_POLAR MASK OFF BITS 10, FIO_POLAR  R0
Edge / Level sensitivity
FIO_EDGE FIO_BOTH MASK OFF BITS 10, 11
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

19. In class exercise – Write 68K code for extern “C” void SetupInterface(void);
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

20. In class exercise – Write Blackfin code for extern “C” void SetupInterface(void);
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada

21. Information taken from Analog Devices On-line Manuals with permission
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.
4/25/2019
Motorola Blackfin Comparison Part , Copyright M. Smith, ECE, University of Calgary, Canada