Blackfin BF533 EZ-KIT Control The O in I/O

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Blackfin BF533 EZ-KIT ControlThe O in I/O

• Activating a FLASH memory output linePart 3
  New instruction recap Tutorial

2
Agenda

• Processors need to send out control signals (high
  / low 1 / 0 true / false)
• General purpose input / output GPIO on processor
  chip (16)
• FLASH memory chip has additional I/O ports
  connected to Ez-Lite KIT LEDs
• Making the FLASH memory I/O port control the
  Ez-KIT LEDs
• The new Blackfin assembly language instructions
  needed

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LEDs connected to FLASH port
BACKFORWARDRIGHTLEFT??? CONTROL ON Might be
connected to other thingsDONT CHANGEBEHAVIOUR
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Activating LEDs -- REVIEW
SOME LAB. 1 FUNCTIONS ARE NOW IN C

• Get the FLASH to work correctly
• InitFlashCPP( )
• Get the Port to work correctly as output for pins
  PB5 ? PB0, leaving other pins unchanged
• InitFlashPortCPP( )
• Write the value we want to LEDs
• WriteFlashLEDASM( int value)
• Read back the value the LEDs show
• int ReadFlashLEDASM( )

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Blackfin Memory Map

• If P0 is 0x20001000thenR0 P0 readsa
  value fromFLASH BANK 0
• If R0 is 6 andP0 is 0x1000 thenP0 R0
  placesa value intoSDRAM

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InitFlashCPP( ) -- REVIEW
SOME LAB. 1 FUNCTIONS ARE NOW IN C

• Get the FLASH to work correctly
• May be many processes running on the Blackfin.
  All these processes may want to use InitFlashCPP(
  )
• InitFlashCPP( )
• If FLASH memory already configured
  return without initializing
• Else
• configure Memory Bank control
  register
• THEN configure Global control
  (turns on the FLASH)
  

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Set the Bank control register

• Kit documentation recommends 0x7BB0

7 cyclesnot 15 11 not 15 B 1011 2 cycles 3
cycles
IGNORE 4 cycles
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Set General Control Register

• Documentation says set to 0xF for this
  particular FLASH chip

ENABLE ALL
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Key issues -- REVIEW
SOME LAB. 1 FUNCTIONS ARE NOW IN C

• InitFlashCPP( )
• Does not sound too big a deal
• Set pointer to EBIU_AMBCTLO
• Then value 0x7BB07BB0
• Then use pointer value
• Then make sure write occurs NOW as this
  processor can delay doing writes until
  convenient
• Do the same for the other 32 bit registers

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Obvious problem value needed EBIU_AMBCTL0 ?
Code review2 obviouserrors SAME ERRORS ARE
POSSIBLE IN C VERSION
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Corrected code still fails
No in a define statement No spaces in
number Spell check 0 not O DEFECTS in code
process Pair programming cost 3 5
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MIPS and Blackfin behave same

• You cant load a 32-bit register with a 32-bit
  immediate value using one instruction
• WRONG R0 0x7BB07BB0
• Must load low 16-bit of register R0.L
  0x7BB0
• Then load high 16-bits of register R0.H
  0x7B00
• You handle P0 0xFFC00A04
• REMEMBER C can introduce similar errors, but
  with different detail

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More readable code
Selfdocumenting code I do defineand then
cut-and-pastethe label
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WriteFlashLEDASM(long in_value)
STILL IN BF533 ASSEMBLY CODE

• Write 1 (on) or 0 (off) to the Port to
  activate LEDs connected to pins PB5 ? PB0,
  leaving other pins unchanged.

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WriteFlashLEDASM(long in_value)
STILL IN BF533 ASSEMBLY CODE

• Read LED data register into processor data
  register (makes a copy)
• Keep top 2 bits (AND operation) of copy
• Keep bottom 6 bits of in-par 32-bit in_value
• OR the two processor data registers
• Write modified copy back into LED data
  register
• PROBLEM byte read and writes

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Now identify the registers to use
STILL IN BF533 ASSEMBLY CODE

• In_par is in R0
• We can use R1, R2 and R3 without saving registers
  to the stack

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Add in the code we understand
STILL IN BF533 ASSEMBLY CODE
Fixed typo Still anothersyntaxproblem
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8 bit and 32 bit writes

• P0 R0 32-bit write (4 bytes)
• Places all 32-bits of processor data register
  into long word (32 bit) address starting at
  memory location P0
• If P0 0x1000 then place 32-bit value at
  memory location 0x1000
• BP0 R0 8-bit write
• Places bottom 8-bits of processor data register
  into byte (8 bit) address starting at memory
  location P0

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8 bit and 32 bit reads

• R0 P0 32-bit read (4 bytes)
• Places all 32-bits of long word (32 bit)
  address starting at memory location P0 into
  processor data register
• If P0 0x1000 then place 32-bit value at
  memory location 0x1000
• R0 BP0 (Z) 8-bit read
• Places byte (8 bit) address starting at memory
  location P0 into bottom 8-bits of processor
  data register and puts 0 into the top 24 bits
  of register
• Must convert 8-bit read operation into a 32
  bit store in register operation

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Add byte read and write operations
Is this correct for keeping top 2 bits of an
8-bit value? DEFECT if not corrected Still
syntaxproblems ERRORS Fix as exercise
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InitFlashPortCPP() to complete
NOW IN C

• Set direction to 1 on lower pins leaving other
  direction values unchanged around 12 lines Read
  direction byte register into processor data
  register (makes a copy)
• Set another processor data register to 0x3F
• OR the two data registers (HOW?)
• Write modified copy back into direction byte
  register

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InitFlashCPP( ) -- Exercise

• InitFlashCPP( )
• If FLASH memory already configured
  return without initializing
• Else
• configure Memory Bank control
  register
• THEN configure Global control
  (turns on the FLASH)
  
• -- 21 instructions many
  cut-and-paste-modify

IF CLOCK ACTIVATED THEN ASSUME ANOTHER PROCESS
HAS ALREADY SET THE FLASH AND on BIT 0 of
EBIU_AMGCTL register followed by IF set then
JUMP
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• Work in pairs for the solutions
• These exercises will form part of take-home quiz
  1
• IF-THEN-ELSE SYNTAX
• Do bits 7 to 4 of register R0 contain 12???
• R0 ????
• R1 0x000000F0 // MASK
• R2 0x000000C0 // Expected value
• R1 R0 R1 // KEEP old value
• CC R1 R2 // Check to see if 12 is
  there
• IF CC JUMP IS_TRUE
• IF !CC JUMP IS_FALSE

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This slide is not in the course notes
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This slide is not in the course notes
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This slide is not in the course notes
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Agenda

• Processors need to send out control signals (high
  / low 1 / 0 true / false)
• General purpose input / output GPIO on processor
  chip (16)
• FLASH memory chip has additional I/O ports
  connected to Ez-Lite KIT LEDs
• Making the FLASH memory I/O port control the
  Ez-KIT LEDs
• The new Blackfin assembly language instructions
  needed