Digital Filter Block (DFB) Assembler - Component - DFB V1.10 Datasheet.pdf

PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
1.0
Features
 Provides an editor to enter the assembler
instructions to configure the DFB block and an
assembler that converts the assembly
instructions to instruction words.


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
Supports simulation of the assembly instructions.
Supports a code optimization option that provides
a mechanism to incorporate up to 128 very large
instruction words inside the DFB Code RAM.
Provides hardware signals such as DMA requests, DSI inputs and outputs, and interrupt
lines.
Supports semaphores to interact with the system software and the option to tie the
semaphores to hardware signals.
General Description
The digital filter block (DFB) in PSoC 3 and PSoC 5 can be used as mini DSP processor and
allows you to configure the DFB using assembly instructions. The component assembles the
instructions entered in the editor and generates the corresponding hex code words, which can be
loaded into the DFB. It also includes a simulator, which helps the user to simulate and debug the
assembly instructions.
The DFB consists of a programmable 24*24 multiplier/accumulator (MAC), an arithmetic logic
unit (ALU), shifter, and various program and data memory to store instructions and data. The
DFB runs on the bus clock, and can interface with both CPU and DMA. It can be used to offload
the CPU and can speed up arithmetic calculations that involve intensive multiply accumulate
operations. Typical operations you can use the DFB component to implement include: vector
operations, matrix operations, filtering operations, and signal processing.
See the Functional Description for details about the DFB.
Cypress Semiconductor Corporation • 198 Champion Court • San Jose, CA 95134-1709 • 408-943-2600
Document Number: 001-79373 Rev. *A
Revised August 4, 2015
Digital Filter Block (DFB) Assembler
PSoC® Creator™ Component Datasheet
Input/Output Connections
This section describes the input and output connections for the DFB. An asterisk (*) in the list of
I/Os means that the I/O may be hidden on the symbol under the conditions listed in the
description of that I/O.
in_1 – Input*
Input terminal. Used to allow some DFB control and visibility to other resources on the chip,
particularly the UDBs. This input displays when the Input 1 option is selected in the Configure
dialog.
in_2 – Input*
Input terminal. Used to allow some DFB control and visibility to other resources on the chip,
particularly the UDBs. This input displays when the Input 2 option is selected in the Configure
dialog.
out_1– Output*
Output terminal. Allows the DFB signals to control other on-chip resources, particularly the
UDBs. This output displays when the Output 1 option is selected in the Configure dialog.
out_2– Output*
Output terminal. Allows the DFB signals to control other on-chip resources, particularly the
UDBs. This output displays when the Output 2 option is selected in the Configure dialog.
dma_req_a – Output*
DMA request output signal. It can be associated with the holding register or semaphore bits and
is particularly useful to trigger DMA channels. This output displays when the DMA Request A
Source option is selected in the Configure dialog.
If the DMA request signal is configured to be associated with the output holding register, it
generates a level-sensed signal to the DMA that is cleared when the register is read.
If the DMA request signal is configured to be generated by a semaphore, it creates a single-cycle
high pulse.
dma_req_b – Output*
DMA request output signal. It can be associated with the holding register or semaphore bits and
is particularly useful to trigger DMA channels. This output displays when the DMA Request B
Source option is selected in the Configure dialog.
If the DMA request signal is configured to be associated with the output holding register, it
generates a level-sensed signal to the DMA that is cleared when the register is read.
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Document Number: 001-79373 Rev. *A
PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
If the DMA request signal is configured to be generated by a semaphore, it creates a single-cycle
high pulse.
interrupt – Output
Output of system interrupts. It can be associated with the holding registers and with semaphore
bits.
Component Parameters
Drag a DFB onto your design and double-click it to open the Configure dialog. The Configure
dialog contains several tabs with different parameters to set up the DFB component.
Configure Tab
Document Number: 001-79373 Rev. *A
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Digital Filter Block (DFB) Assembler
PSoC® Creator™ Component Datasheet
Connections




Enable input terminal 1
Enable input terminal 2
Enable output terminal 1
Enable output terminal 2
Output 1 Source
Determines the internal signal that is mapped to the output global signal 1.

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
Run bit – This is the same bit as the RUN bit in the DFB_CR register.
Semaphore 0
Semaphore 1
Interrupt – This is the same signal as the primary DFB Interrupt output signal.
Output 2 Source
Determines the internal signal that is mapped to the output global signal 2.


Semaphore 2
Datapath sign – This signal asserts any time the output of the ALU in the datapath unit is
negative. It remains high for each cycle this condition is true.

Datapath threshold crossed – This signal asserts any time the threshold of 0 is crossed in
the ALU when one of the following instructions is executing: tdeca, tsuba, tsubb, taddabsa, or
taddabsb. It remains high for each cycle this condition is true.

Datapath ALU equals 0 – This signal asserts high when the output of the ALU in the
Datapath unit equals 0 and one of the following ALU commands is executing: tdeca, tsuba,
tsubb, taddabsa, or taddabsb. It remains high for each cycle this condition is true.
Interrupt Generation Sources
Configures the events on which interrupts will be generated:
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Semaphore 0
Semaphore 1
Semaphore 2
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Document Number: 001-79373 Rev. *A
PSoC® Creator™ Component Datasheet


Digital Filter Block (DFB) Assembler
Data in Holding Register A
Data in Holding Register B
DMA Request Mode
Configures DMA Request sources. If DMA Request is not equal to None, a DMA request output
terminal is created.

DMA Request A Source:
 None
 Data in Holding Register A
 Semaphore 0
 Semaphore 1

DMA Request B Source:
 None
 Data in Holding Register B
 Semaphore 0
 Semaphore 1
This is all controlled using CSR configuration. When a DMA semaphore is programmed as a
DMA_REQ, the HW converts any write of a ‘1’ to that semaphore to a single-cycle strobe. This
clears the semaphore after one cycle. So, if a semaphore will be used as a source for a DMA
request signal, it is cleared automatically.
Code Tab
The Code tab provides an editor to enter the assembler instructions, an assembly mechanism to
verify and assemble code, and a simulator to simulate instructions.
Document Number: 001-79373 Rev. *A
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Digital Filter Block (DFB) Assembler
PSoC® Creator™ Component Datasheet
Assemble
Assembles entered DFB assembler instructions. Status and error messages are displayed in the
Output window of the customizer. Keyboard shortcut – [F6]
Simulate Continuously
The simulator runs until Bus Input Data (Bus1 Data and Bus2 Data) is exhausted. Bus1 data and
Bus2 data are the input data for simulation that corresponds to data that will be streamed to DFB
staging registers. Simulated contents of DFB sub-blocks after each instruction execution are
displayed in the Output window. Keyboard shortcut – [F5]
After simulation starts, use [Shift] F5] to stop it.
Simulate Step by Step
The simulator runs step by step until Bus Input Data is exhausted. At each step, the lines of code
being executed are highlighted in the code editor. Simulation properties are displayed in the
Simulation Properties panel. Keyboard shortcut – [F7]
After simulation starts, use [F8] to execute the next simulation step.
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Document Number: 001-79373 Rev. *A
PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
Optimize Assembly States
Enables the compactor feature. The compactor removes the 64-word program size barrier,
allowing you to incorporate up to 128 instruction words inside the DFB Code RAM. If the
Optimize Assembly States option is selected, the code compacting feature runs after
successful code assembly.
Code Editor
Displays DFB assembler code with highlighting. It highlights comments, labels, commands, and
values with different colors.
Figure 1. Text Editor Toolbar
Text Editor
Open file: Opens a text file with DFB assembler code. Keyboard shortcut – [Ctrl] [O]
Save file: Saves a text file with DFB Assembler code. Keyboard shortcut – [Ctrl] [S]
Other text editor features: Includes cut, copy, paste, undo, redo, print, print preview,
find/replace text, comment, uncomment, and other functionality.
Output panel
Displays log information for the assembly, compactor, and simulator processes. Lines with error
text are highlighted red, lines that indicate successful operations are highlighted green. If you
double-click on a line with error text, the customizer automatically activates the Code Editor and
selects the line where the error is located.
Use the keyboard shortcut [Alt] [C] to clear the log.
Error List
Displays a list of errors, warnings, and notes. If you double-click on an error, the customizer
automatically activates Code Editor and selects the line where error is located.
Bus1
Provides data for STAGEA input for the simulator. Enter it as a 24-bit value in hex, decimal, or
binary format. For example, 99 is decimal, 0x63 is hex, and 0b1100011 is binary.
Bus2
Provides data for STAGEB input for the simulator. Enter it as a 24-bit value in hex, decimal, or
binary format.
Document Number: 001-79373 Rev. *A
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Digital Filter Block (DFB) Assembler
PSoC® Creator™ Component Datasheet
Bus data import
Imports data to the Bus1/Bus2 text fields. Supports .txt and .data (an old data format that was
used in the C-based implementation of the simulator) file formats.
Bus data export
Exports data from the Bus1/Bus2 text fields. Supports .txt and .data file formats.
Simulator Properties
Provides functionality to change input values and semaphores and view internal simulator values
between simulations.
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GlobalInput1: Read/Write field
GlobalInput2: Read/Write field
Semaphore0: Read/Write field
Semaphore1: Read/Write field
Semaphore2: Read/Write field
Cycle: Displays current cycle number
RamA Index: Read-only field that represents the current index in RAM A.
RamB Index: Read-only field that represents the current index in RAM B.
Ram Selected: Read-only field that shows which ram (A or B) is currently executed
Application Programming Interface
Application Programming Interface (API) routines allow you to configure the component using
software. The following table lists and describes the interface to each function. The subsequent
sections discuss each function in more detail.
By default, PSoC Creator assigns the instance name “DFB_1” to the first instance of a
component in a given design. You can rename it to any unique value that follows the syntactic
rules for identifiers. The instance name becomes the prefix of every global function name,
variable, and constant symbol. For readability, the instance name used in the following table is
“DFB.”
Function
DFB_Start()
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Description
Initializes and enables the DFB component using the DFB_Init() and DFB_Enable()
functions.
Document Number: 001-79373 Rev. *A
PSoC® Creator™ Component Datasheet
Function
Digital Filter Block (DFB) Assembler
Description
DFB_Stop()
Turns off the run bit. If DMA control is used to feed the channels, allows arguments to turn
off one of the TD channels.
DFB_Pause()
Pauses DFB and enables writing to the DFB RAM.
DFB_Resume()
Disables writing to the DFB RAM, clears any pending interrupts, disconnects the DFB
RAM from the data bus, and runs the DFB.
DFB_SetCoherency()
Sets the coherency key to low/mid/high byte based on the coherencyKey parameter that is
passed to the DFB.
DFB_SetDalign()
Allows 9- to 16-bit input and output samples to travel as 16-bit values on the AHB bus.
DFB_LoadDataRAMA()
Loads data to RAMA DFB memory.
DFB_LoadDataRAMB()
Loads data to RAMB DFB memory.
DFB_LoadInputValue()
Loads the input value into the selected channel.
DFB_GetOutputValue()
Gets the value from one of the DFB output holding registers.
DFB_SetInterruptMode()
Assigns the events that will trigger a DFB interrupt.
DFB_GetInterruptSource() Looks at the DFB_SR register to see which interrupt sources have been triggered.
DFB_ClearInterrupt()
Clears the interrupt request.
DFB_SetDMAMode()
Assigns the events that will trigger a DMA request for the DFB.
DFB_SetSemaphores()
Sets semaphores specified with a 1.
DFB_ClearSemaphores()
Clears semaphores specified with a 1.
DFB_GetSemaphores()
Checks the current status of the DFB semaphores and returns that value.
DFB_SetOutput1Source()
Chooses which internal signals will be mapped to output 1.
DFB_SetOutput2Source()
Chooses which internal signals will be mapped to output 2.
DFB_Sleep()
Prepares the DFB component to go to sleep.
DFB_Wakeup()
Prepares DFB Component to wake up.
DFB_Init()
Initializes or restores the default DFB configuration provided with the customizer.
DFB_Enable()
Enables the DFB hardware block. Sets the DFB run bit. Powers on the DFB block.
DFB_SaveConfig(void)
Saves the user configuration of the DFB nonretention registers. This routine is called by
DFB_Sleep() to save the component configuration before entering sleep.
DFB_RestoreConfig()
Restores the user configuration of the DFB nonretention registers. This routine is called by
DFB_Wakeup() to restore the component configuration when exiting sleep.
Document Number: 001-79373 Rev. *A
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PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
Global Variables
Variable
DFB_initVar
Description
Indicates whether the DFB has been initialized. The variable is initialized to 0 and set to 1 the
first time DFB_Start() is called. This allows the component to restart without reinitialization after
the first call to the DFB_Start() routine.
If reinitialization of the component is required, then the DFB_Init() function can be called before
the DFB_Start() or DFB_Enable() function.
void DFB_Start(void)
Description:
This function initializes and enables the DFB component using the DFB_Init() and
DFB_Enable() functions.
Parameters:
None
Return Value: None
Side Effects:
None
void DFB_Stop(void)
Description:
This function turns off the run bit. If DMA control is used to feed the channels, DFB_Stop()
allows arguments to turn off one of the TD channels.
Parameters:
None
Return Value: None
Side Effects:
Disables power to the DFB core.
void DFB_Pause(void)
Description:
Parameters:
This function pauses the DFB and enables writing to the DFB RAM.

Turns off the run bit

Connects the DFB RAM to the data bus,

Clears the DFB run bit and passes the control of all DFB RAMs onto the bus
None
Return Value: None
Side Effects:
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None
Document Number: 001-79373 Rev. *A
PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
void DFB_Resume(void)
Description:
This function disables writing to the DFB RAM, clears any pending interrupts, disconnects
the DFB RAM from the data bus, and runs the DFB. It passes the control of all DFB RAM to
the DFB and then sets the run bit.
Parameters:
None
Return Value: None
Side Effects:
None
void DFB_SetCoherency(uint8 coherencyKeyByte)
Description:
This function sets the coherency key to low, med, or high byte based on the coherencyKey
parameter that is passed to the DFB.
DFB_SetCoherency() allows you to select which of the three bytes of each of STAGEA,
STAGEB, HOLDA, and HOLDB will be used as the key coherency byte. Coherency refers to
the HW added to this block to protect against block malfunctions. This is needed in cases
where register fields are wider than the bus access, which leaves intervals when fields are
partially written or read (incoherent). The key coherency byte is the way the SW tells the HW
which byte of the field will be written or read last when you want to update the field. When
the key byte is written or read, the field is flagged coherent. If any other byte is written or
read, the field is flagged incoherent.
Parameters:
uint8 coherencyKeyByte: Specifies bits in the DFB Coherency register.
Value
Description
DFB_STGA_KEY_LOW
The key coherency byte of the Staging A register is a low byte.
DFB_STGA_KEY_MID
The key coherency byte of the Staging A register is a med byte.
DFB_STGA_KEY_HIGH
The key coherency byte of the Staging A register is a high byte.
DFB_STGB_KEY_LOW
The key coherency byte of the Staging B register is a low byte.
DFB_STGB_KEY_MID
The key coherency byte of the Staging B register is a med byte.
DFB_STGB_KEY_HIGH
The key coherency byte of the Staging B register is a high byte.
DFB_HOLDA_KEY_LOW
The key coherency byte of the Holding A register is a low byte.
DFB_HOLDA_KEY_MID
The key coherency byte of the Holding A register is a med byte.
DFB_HOLDA_KEY_HIGH The key coherency byte of the Holding A register is a high byte.
DFB_HOLDB_KEY_LOW
The key coherency byte of the Holding B register is a low byte.
DFB_HOLDB_KEY_MID
The key coherency byte of the Holding B register is a med byte.
DFB_HOLDB_KEY_HIGH The key coherency byte of the Holding B register is a high byte.
Return Value: None
Side Effects:
Coherency affects data loading using the DFB_LoadInputValue() function and data retrieval
using the DFB_GetOutputValue() function.
Note
Default key byte configuration for Staging A and B, and Holding A and B registers is high
byte.
Document Number: 001-79373 Rev. *A
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PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
void DFB_SetDalign(uint8 dalignKeyByte)
Description:
This feature allows 9- to 16-bit input and output samples to travel as 16-bit values on the
AHB bus. These bits, when set high, cause an 8-bit shift in the data to all access of the
corresponding staging and holding registers. Because the DFB datapath is MSB aligned, it is
convenient to the system SW to align values on bits 23:8 of the Staging and Holding register
to bits 15:0 of the bus. A read of this register produces the last value written to the register.
Parameters:
uint8 dalignKeyByte: Specifies bits in the DFB Data Alignment register.
Value
Description
DFB_STGA_DALIGN_LOW
Writes normally
DFB_STGA_DALIGN_HIGH
Writes shifted left by eight bits
DFB_STGB_DALIGN_LOW
Writes normally
DFB_STGB_DALIGN_HIGH
Writes shifted left by eight bits
DFB_HOLDA_DALIGN_LOW
Reads normally
DFB_HOLDA_DALIGN_HIGH
Writes shifted left by eight bits
DFB_HOLDB_DALIGN_LOW
Reads normally
DFB_HOLDB_DALIGN_HIGH
Writes shifted left by eight bits
Return Value: None
Side Effects:
None
void DFB_LoadDataRAMA(int32 * ptr, uint32 * addr, uint8 size)
Description:
This function loads data to the DFB RAM A memory.
Parameters:
uint32 * ptr: Pointer on data source for load
uint32 * addr: Start address for loading the data in DFB RAM A.
uint8 size: Number of data words to load.
Return Value:
Value
Side Effects:
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Description
DFB_SUCCESS
Loading data is successful.
DFB_NAME`_ADDRESS_OUT_OF_RANGE
Error code: indicates that the address is
out of range.
DFB_DATA_OUT_OF_RANGE
Error code: indicates a data overflow
error.
This function does not stop the DFB if it is already started. The recommended method is to
call DFB_Init(), DFB_LoadDataRAMA(), then DFB_Enable().
Document Number: 001-79373 Rev. *A
PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
void DFB_LoadDataRAMB(uint32 * ptr, uint32 * addr, uint8 size)
Description:
This function loads data to DFB RAM B memory.
Parameters:
uint32 * ptr: Pointer on data source for load
uint32 * addr: Start address for loading the data in DFB RAM B
uint8 size: Number of data words to load
Return Value:
Side Effects:
Value
Description
DFB_SUCCESS
Loading data is successful
DFB_NAME`_ADDRESS_OUT_OF_RANGE
Error code: indicates that the address is
out of range
DFB_DATA_OUT_OF_RANGE
Error code: indicates a data overflow
error.
This function does not stop the DFB if it is already started. The recommended method is to
call DFB_Init(), DFB_LoadDataRAMB(), then DFB_Enable().
void DFB_LoadInputValue(uint8 channel, uint32 sample)
Description:
This function loads the input value into the selected channel.
Parameters:
channel: Use either DFB_CHANNEL_A (1) or DFB_CHANNEL_B (0) as arguments to the
function.
sample: 24-bit, right-justified input sample
Return Value: None
Side Effects:
None
Note:
The write order is important. When the high byte is loaded, the DFB sets the input ready bit.
Pay attention to byte order if coherency or data alignment is changed.
int32 DFB_GetOutputValue(uint8 channel)
Description:
This function gets the value from one of the DFB Output Holding registers.
Parameters:
channel: Use either DFB_CHANNEL_A (1) or DFB_CHANNEL_B (0) as arguments to the
function.
Return Value: The current output value in the chosen channel’s holding register. This is a 24-bit number
packed into the least-significant three bytes of the output word, or 0xFF000000 for invalid
channel numbers
Side Effects:
None
Note:
Because of the architecture of the DFB, any value read from the holding A or B registers will
be MSB aligned unless shifted otherwise by the datapath shifter. Pay attention to byte order
if coherency or data alignment is changed.
Document Number: 001-79373 Rev. *A
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PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
void DFB_SetInterruptMode(uint8 events)
Description:
This function assigns the events that trigger a DFB interrupt.
Parameters:
events: Bits[0:5] of events represent the events that trigger DFB interrupts.
Value
Description
DFB_HOLDA
Interrupt is generated each time new valid data is written into output
holding register A.
DFB_HOLDB
Interrupt is generated each time new valid data is written into output
holding register B.
DFB_SEMA0
Interrupt is generated each time a '1' is written into semaphore
register bit 0.
DFB_SEMA1
Interrupt is generated each time a '1' is written into semaphore
register bit 1.
DFB_SEMA2
Interrupt is generated each time a '1' is written into semaphore
register bit 2.
Return Value: None
Side Effects:
None
Note:
Do not configure semaphore 0 and semaphore 1 for both a DMA request and for an interrupt
event. This is because, after one clock cycle, the system automatically clears any
semaphore that triggered a DMA request.
uint8 DFB_GetInterruptSource(void)
Description:
This function looks at the DFB_SR register to see which interrupt sources have been
triggered.
Parameters:
None
Return Value: uint8 value in which bits[0:5] of represent the events that triggered the DFB interrupt
Value
Side Effects:
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Description
DFB_HOLDA
Holding register A is a source of the current interrupt.
DFB_HOLDB
Holding register B is a source of the current interrupt.
DFB_SEMA0
Semaphore register bit 0 is a source of the current interrupt.
DFB_SEMA1
Semaphore register bit 1 is a source of the current interrupt.
DFB_SEMA2
Semaphore register bit 2 is a source of the current interrupt.
None
Document Number: 001-79373 Rev. *A
PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
void DFB_ClearInterrupt(uint8 interruptMask)
Description:
This function clears the interrupt request.
Parameters:
interruptMask: Mask of interrupts to clear
Value
Description
DFB_HOLDA
Clear interrupt from holding register A. (Reading holding register A
also clears this bit.)
DFB_HOLDB
Clear interrupt from holding register B. (Reading holding register B
also clears this bit.)
DFB_SEMA0
Clear interrupt from semaphore register bit 0.
DFB_SEMA1
Clear interrupt from semaphore register bit 1.
DFB_SEMA2
Clear interrupt from semaphore register bit 2.
Return Value: None
Side Effects:
Clearing semaphore interrupts also clears semaphore bits.
void DFB_SetDMAMode(uint8 events)
Description:
This function assigns the events that trigger a DMA request for the DFB. Two different DMA
requests can be triggered.
Parameters:
events: A set of four bits that configure what event, if any, triggers a DMA request for the
DFB.
Value
Description
DFB_DMAREQ1_DISABLED
No request is generated
DFB_DMAREQ1_HOLDA
Output value ready in the holding register on channel A
DFB_DMAREQ1_SEM0
Semaphore 0
DFB_DMAREQ1_SEM1
Semaphore 1
DFB_DMAREQ2_DISABLED
No request is generated
DFB_DMAREQ2_HOLDB
Output value ready in the holding register on channel B
DFB_DMAREQ2_SEM0
Semaphore 0
DFB_DMAREQ2_SEM1
Semaphore 1
Return Value: None
Side Effects:
None
Note:
Do not configure semaphore 0 and semaphore 1 as both a DMA request and an interrupt
event. This is because, after one clock cycle, the system automatically clears any
semaphore that triggered a DMA request.
Document Number: 001-79373 Rev. *A
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PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
void DFB_SetSemaphores(uint8 mask)
Description:
This function sets semaphores specified with a 1.
Parameters:
mask: Mask specifying the bits to set
Value
Description
DFB_SEMAPHORE0
Semaphore 0
DFB_SEMAPHORE1
Semaphore 1
DFB_SEMAPHORE2
Semaphore 2
Return Value: None
Side Effects:
None
void DFB_ClearSemaphores(uint8 mask)
Description:
This function clears semaphores specified with a 1.
Parameters:
mask: Mask specifying the bits to clear.
Value
Description
DFB_SEMAPHORE0
Semaphore 0
DFB_SEMAPHORE1
Semaphore 1
DFB_SEMAPHORE2
Semaphore 2
Return Value: None
Side Effects:
None
uint8 DFB_GetSemaphores(void)
Description:
This function checks the current status of the DFB semaphores and returns that value.
Parameters:
None
Return Value: uint8 value between 0 and 7 where bit 0 represents semaphore 0, and so on.
Value
Side Effects:
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Description
DFB_SEMAPHORE0
Semaphore 0
DFB_SEMAPHORE1
Semaphore 1
DFB_SEMAPHORE2
Semaphore 2
None
Document Number: 001-79373 Rev. *A
PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
void DFB_SetOutput1Source(uint8 source)
Description:
This function allows you to choose which internal signals are mapped to output 1.
Parameters:
source: Internal signal that is mapped to output global signal 1.
Signal
Description
DFB_RUN
DFB run bit. This is the same bit as the run
bit in the DFB_CR register.
DFB_SEM0
Semaphore Bit 0.
DFB_SEM1
Semaphore Bit 1.
DFB_DFB_INTR
DFB Interrupt. This is the same signal as
the primary DFB interrupt output signal.
Return Value: None
Side Effects:
None
void DFB_SetOutput2Source(uint8 source)
Description:
This function allows you to choose which internal signals are mapped to output 2.
Parameters:
source: Internal signal that is mapped to output global signal 2.
Signal
Description
DFB_SEM2
Semaphore bit 2.
DFB_DPSIGN
Datapath sign. This signal asserts any time the output of the ALU in
the datapath unit is negative. It remains high for each cycle this
condition is true.
DFB_DPTHRASH
Datapath threshold crossed. This signal asserts any time the
threshold of 0 is crossed in the ALU and one of the following
instructions is executing: tdeca, tsuba, tsubb, taddabsa, or
taddabsb. It remains high for each cycle this condition is true.
DFB_DPEQ
Datapath ALU = 0. This signal asserts high when the output of the
ALU in the datapath unit equals 0 and one of the following ALU
commands is executing: tdeca, tsuba, tsubb, taddabsa, or
taddabsb. It remains high for each cycle this condition is true.
Return Value: None
Side Effects:
None
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Digital Filter Block (DFB) Assembler
PSoC® Creator™ Component Datasheet
void DFB_Sleep(void)
Description:
This is the preferred routine to prepare the component for sleep. The DFB_Sleep() routine
saves the current component state. Then it calls the DFB_Stop() function and calls
DFB_SaveConfig() to save the hardware configuration.
Call the DFB_Sleep() function before calling the CyPmSleep() or the CyPmHibernate()
function. See the PSoC Creator System Reference Guide for more information about power
management functions.
Parameters:
None
Return Value: None
Side Effects:
None
void DFB_Wakeup(void)
Description:
This is the preferred routine to restore the component to the state when DFB_Sleep() was
called. The DFB_Wakeup() function calls the DFB_RestoreConfig() function to restore the
configuration. If the component was enabled before the DFB_Sleep() function was called, the
DFB_Wakeup() function will also re-enable the component.
Parameters:
None
Return Value: None
Side Effects:
Calling the DFB_Wakeup() function without first calling the DFB_Sleep() or
DFB_SaveConfig() function may produce unexpected behavior.
void DFB_Init(void)
Description:
Parameters:
This function initializes or restores the default DFB component configuration provided with
the customizer:

Powers on the DFB (PM_ACT_CFG) and the RAM (DFB_RAM_EN)

Moves CSA/CSB/FSM/DataA/DataB/Address calculation unit (ACU) data to the DFB
RAM using an 8051/ARM core

Changes RAM DIR to DFB

Sets the interrupt mode

Sets the DMA mode

Sets the DSI outputs

Clears all semaphore bits and pending interrupts
None
Return Value: None
Side Effects:
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All registers will be reset to their initial values. This reinitializes the component. This function
turns off the run bit and enables power to the DFB block.
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PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
void DFB_Enable(void)
Description:
This function enables the DFB hardware block, sets the DFB run bit, and powers on the DFB
block.
Parameters:
None
Return Value: None
Side Effects:
None
void DFB_SaveConfig(void)
Description:
This function saves the component configuration and nonretention registers. It also saves the
current component parameter values, as defined in the Configure dialog or as modified by
appropriate APIs. This function is called by the DFB_Sleep() function.
Parameters:
None
Return Value: None
Side Effects:
None
void DFB_RestoreConfig(void)
Description:
This function restores the component configuration and nonretention registers. It also
restores the component parameter values to what they were before calling the DFB_Sleep()
function.
Parameters:
None
Return Value: None
Side Effects:
Calling this function without first calling the DFB_Sleep() or DFB_SaveConfig() function can
produce unexpected behavior.
Defines
ClearInterruptSource(event) – Macro for clearing interrupts
Sample Firmware Source Code
PSoC Creator provides many example projects that include schematics and example code in the
Find Example Project dialog. For component-specific examples, open the dialog from the
Component Catalog or an instance of the component in a schematic. For general examples,
open the dialog from the Start Page or File menu. As needed, use the Filter Options in the
dialog to narrow the list of projects available to select.
Refer to the “Find Example Project” topic in the PSoC Creator Help for more information.
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Digital Filter Block (DFB) Assembler
PSoC® Creator™ Component Datasheet
Functional Description
The Digital Filter Block is a 24-bit fixed-point, programmable limited-scope DSP with a 24*24
Multiply and Accumulate Unit (MAC), a multifunction Arithmetic Logic Unit (ALU), and data
routing, shifting, holding, and rounding functions.
Other important features of the DFB are:








Two 24-bit-wide streaming data channels
Two sets of control store RAMs, each of which can store up to 64 control words
Two sets of data RAMs, each of which can store up to 128 24-bit-wide words
Address calculation units (ACU) to calculate the data RAM address and two ACU RAMs,
each of which can store up to 16 absolute data RAM addresses
Two sets of 32*32 Finite State Machine RAM to store the control flow (branching) information
One interrupt and two DMA request channels
Three semaphore bits to interact with system software
Data alignment and coherency protection support options for input and output registers
The DFB supports up to two streaming data channels, where programming instructions, historic
data and filter coefficients, and results are stored locally with new periodic data samples received
from the AHB interface. In addition, the system SW can ‘load sample or coefficient data in or out
of the DFB data RAMs, reprogram for different filter operation in ‘block mode’, or both. This
allows for multichannel processing or deeper filters than are supported in local memory. The
block provides SW-configurable interrupt and two-DMA-channel support. There are three
semaphore bits for SW to interact with the DSP assembly program.
The DFB has two 24-bit input staging registers and two 24-bit output holding registers. These
registers can be accessed by both the DFB and the AHB bus (CPU/DMA). Input data is generally
streamed into staging registers using CPU or DMA and output is streamed out through DFB
holding registers. The two sets of input /output registers make it well suited for stereo data
processing applications (two channels in parallel). These in/out registers support 32-bit, 16-bit,
and 8-bit accesses and have coherency protection HW allowing them to be written or read in
less than 32-bit accesses.
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PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
Figure 2. DFB Application Diagram
The typical use model is for data to be supplied to the DFB over the system bus from another onchip system data source such as an ADC. The data typically passes through main memory or is
directly transferred from another chip resource through DMA.
The DFB architecture supports parallel operation of the ACUs, ALU, MAC, and shifter. The
operations allowed for each are encoded in bit fields. The basic assembly instruction set is given
in terms of these functions. The instruction pipelining follows Figure 3 for the DFB processor.
The diagram shows the locations of the pipeline registers so you can determine the instruction
pipeline latency. While the ACU/DPRAM, MAC, and ALU/shifter all can operate in parallel, the
instruction delay from one block to the next is one cycle of overhead. Suppose, for example, that
you wanted to specify a new ACU address, multiply and accumulate based on that address, then
see if the output exceeds a threshold. You would need to schedule the ACU address in the first
cycle, the MAC in the second cycle, and the threshold in the third cycle after that. If the threshold
flag from the data path is to be used in the controller for a branch, that branch cannot happen
until the fourth cycle in the sequence. This is not usually an issue, as algorithms can be
scheduled to avoid four-cycle delays in branches. Typically, an algorithm will see a one-cycle
delay between the last command and the branch, because the steps leading up to the branch
can be combined with previous statements in the algorithmic flow. The ACUs are positioned so
there is no cycle delay between detection and branching.
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Page 21 of 42
Digital Filter Block (DFB) Assembler
PSoC® Creator™ Component Datasheet
Figure 3. Data Flow/Pipelining Diagram
Any of the semaphore bits can optionally be programmed to be associated with the system
interrupt signal or either of the DMA_REQ outputs, leaving the DFB, either of the output DSI
signals (Out_1, Out_2).
Data in DFB and particularly in DATA RAM A/B memories are represented in two's complement
format. The DFB operates on 24-bit signed arithmetic values. Valid values are from 0 to
16,777,215. The DFB component is oriented on filtering algorithms and has a range from –1 to 1.
Value 1 (0.9999999) equals 0x7FFFFF (8388607), 0 equals 0x000000 (0), –1 equals 0x800000
(8388608), –0.0000001 equals 0xFFFFFF (16,777,215), 0.0000001 equals 0x000001 (1). The
24th bit is the sign.
DFB Compactor
Using the optimizer feature (Optimize Assembly States tab), all 128 memory entries are available
for program store in the DFB. The DFB supports code flow execution alternating from one 64entry code store to the other, creating zero overhead looping and branches. When the code
stores are not identical, all 128 memory entries are available for programming.
The compactor divides the program into states and puts the program states in one of the two
control stores. The compactor also generates jump addresses between control stores. In a
normal situation, jumps between program states go from one control store to another. A program
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PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
cannot require a jump within the same control store. For example, you have a routine called
FILTER, and it is partitioned to be in RAM A. You also have two routines, R1 and R2, both of
which jump to FILTER. If R1 and R2 are both in RAM B, there is no problem, but if either is in
RAM A, then the program cannot jump. This situation causes an error at assembly. To resolve
this issue, the output panel provides Compactor information such as: the content of RAM A,
RAM B and a description of control finite state machine (CFSM) content. The content of RAM A
and RAM B contains information about program states. The CFSM content description contains
information about jumps between program states.
A code profiler was added to allow you to see where the lines of code were placed in the control
store (cstore). Because the input assembly language is cycle- and line-oriented, there is a oneto-one correspondence between a line in the assembly language and an entry in the cstore. This
allows you to gather meaningful information about how to optimize your code.
When a DFB program has an issue with assembly state optimization, the following error appears
after assembling:
“ERROR: Unable to map to split RAMs. Found N states that can't be mapped. Please analyze
results and verify code can be mapped.”
When the state has indexed as -01, the file shows that the code is not in the correct RAM. You
can deduce the problem by looking at the RAM and state information.
Using the log file, you can construct the block diagram of the flow and identify the block
allocation. To resolve your issue, you can place additional dummy states into your program. In
the case of the problem mentioned earlier, it will cost a single dummy state and a single
instruction. For example, if you have a problem with a jump to the nextState program state, you
can jump to dummy state dummy1. From this state you can jump to nextState. See the following
single instruction.
dummy1:
acu(hold,hold) dmux(sa,sa) alu(hold) mac(hold) jmp(eob, nextState)
The following screenshots show an example of this process.
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Digital Filter Block (DFB) Assembler
PSoC® Creator™ Component Datasheet
Resources
The DFB component uses the dedicated DFB hardware block in the silicon.
API Memory Usage
The component memory usage varies significantly, depending on the compiler, device, number
of APIs used and component configuration. The following table provides the memory usage for
all APIs available in the given component configuration.
The measurements have been done with the associated compiler configured in Release mode
with optimization set for Size. For a specific design the map file generated by the compiler can
be analyzed to determine the memory usage.
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PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
PSoC 3 (Keil_PK51)
Configuration
Default
PSoC 5 (GCC)
PSoC 5LP (GCC)
Flash
SRAM
Flash
SRAM
Flash
SRAM
Bytes
Bytes
Bytes
Bytes
Bytes
Bytes
1432 + size
of DFB
program*
2
1092 +
size of
DFB
program[1]
5
1092 +
size of
DFB
program[1]
5
DFB Data Memory (RAM)
DATA A
DATA B
CS A
CS B
FSM
ACU
128x24
128x24
64x32
64x32
64x32[2]
16x14
The various DFB RAMS can be accessed by the DFB or the system (CPU/DMA) AHB bus, but
not by both at once. In cases where bulk data must be moved into the DFB RAMs, pass the
control of the DFB RAM to the system AHB bus (CPU/DMA), load the new data to the DFB
RAMs, and pass control back to the DFB. The DFB_RAM_DIR register controls whether the DFB
RAMs can be accessed by the DFB or the system bus (CPU/DMA).
RAM Name
Size
Functions
DATA A
128x24
Sample/Coeff Store
DATA B
128x24
Sample/Coeff Store
CS A
64x32
Control Store
CS B
64x32
Control Store
FSM
64x32
Finite state machine RAM
ACU
16x14
Address Store
DC and AC Electrical Characteristics
Specifications are valid for –40 °C ≤ TA ≤ 85 °C and TJ ≤ 100 °C, except where noted.
Specifications are valid for 1.71 V to 5.5 V, except where noted.
1. The size of the DFB program is restricted by the DFB data memory size shown in the following table
2. For current DFB implementation, only half (32x32) of the FSM memory is available.
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PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
DC Specifications
Parameter
Description
DFB operating current
Conditions
Min
Typ
Max
Units
100 kHz (1.3 ksps)
–
0.03
0.05
mA
500 kHz (6.7 ksps)
–
0.16
0.27
mA
1 MHz (13.4 ksps)
–
0.33
0.53
mA
10 MHz (134 ksps)
–
3.3
5.3
mA
48 MHz (644 ksps)
–
15.7
25.5
mA
67 MHz (900 ksps)
–
21.8
35.6
mA
80 MHz (1.07 Msps) (only for
PSoC5)
–
26.1
42.5
mA
Conditions
Min
Typ
Max
Units
PSoC3
DC
–
67.01
MHz
PSoC5
DC
–
80.01
MHz
64-tap FIR at FDFB
AC Specifications
Parameter
FDFB
Description
DFB operating frequency
DFB Assembler
Directive Descriptions
AREA
The “area” directive takes an argument specifying the accessibility of a RAM segment. The
selected RAM may or may not be enclosed in parenthesis:
area(RAM_Name) or area RAM_Name
There are only three RAMs, data_a, data_b, and acu, that you would logically need to access
and modify using the dw (define word) command. Control and CFSM RAM are accessible, but it
does not make sense to manually code them when the assembler is designed to enter those
opcodes for you.
Comments
Comments for the assembler are the same as C style line comments, with the stipulation that
they occupy the entire line.
// Designates the line to be a comment line. Everything is
// ignored by the assembler
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PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
ORG
The “org” directive sets the current location counter (CLC) for the current RAM. Initially, each
RAM’s CLC is set to zero. The value of a location must be an integer and must be constrained to
the set of numbers that represent a valid memory location. Both of the following are acceptable
formats for this instruction.
org(location) or org location
dw
Define Word. After the instruction, the argument is the value that is place in the memory of the
current section and CLC for that section. The CLC then increments. The customizer generates
and displays an error message when the program tries to write a value that exceeds the
maximum value of the RAM. Hexadecimal arguments beginning with the prefix “0x” are
acceptable inputs for the “acu” area. This greatly clarifies the separation between values for side
A and side B in the ACU RAM. Integer values representing 1-2-23 to –1 in 24-bit, 2’s complement
format (0 to 16,777,215) are acceptable inputs for data areas. In an ACU RAM, two 7-bit sides
allow input data using 4-digit hexadecimal inputs. This makes it clear what value is placed in
each side of the 14-bit wide RAM, as the first two digits are entered into side A and the second
two into side B. The valid value range for each side is from 0x00 to 0x7F.
Example:
dw 0x123F
// (Decimal 18 in ACU RAM side A, 63 in side B)
Labels
Labels are user-defined tags to refer to blocks of cstore code. Blocks of code are sections
beginning with a valid label and ending with a jump instruction, which together become a state in
the CFSM. With the exception of the keywords listed as instructions in this document, a label can
be defined by a set of characters that start with a letter and are followed by a colon. Do not put
declarations on the same line as a label. For DFB hardware commands to be executed they
must be located inside of a label/jump block; the two of these together create a state. Two labels
with no jump-terminated block separating them are not permitted.
An example declaration is given.
// MyLabel defines a new state for the cfsm. The location of
// the state’s start in Cstore is attached
MyLabel:
VLIW Commands
Each line of commands defines opcodes in a 32-bit very long instruction word (VLIW). The most
inclusive form of command for a single instruction word is shown below in the required order.
Required commands in each line are emphasized using bold text. The following section outlines
each individual instruction. An instruction of the proper instruction sets should be entered in
between the parentheses. ACU and DMUX instructions both require two instructions separated
by a comma, the first for datapath side A, the second for side B.
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PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
acu(,) addr() dmux(,) alu() mac() shift() write() jump()
Each instruction contributes a short opcode to the VLIW, resulting in a 32-bit instruction control
word for each line.
ACU
The address calculation unit (ACU) outputs the data RAM addresses required for the next
instruction cycle. A single ACU is basically a counter with four registers in a default state of zero.

reg – reg stores the current value that the ACU is operating on and outputs it on every cycle
unless a command specifies otherwise.

freg – freg can be loaded with the value that the data RAMs increment or decrement, when
using the addf and subf commands. For example: load two into freg and you can increment
through the data RAMs by two using ACU’s ‘addf’ instruction.

mreg – mreg stores the maximum value before wraparound to the lreg value when modulus
arithmetic is enabled.

lreg – lreg stores the minimum value before wraparound to the mreg value when modulus
arithmetic is enabled.
Modulus arithmetic prevents the ACU from incrementing past the value of mreg and from
decrementing below the value of lreg. The ACU will produce unexpected (although deterministic)
results when modulus arithmetic is enabled and the current address is located outside of the lreg
to mreg range. Good DFB programming practice requires that you ensure, using the “read”
command or through careful inspection, that the value the ACU points to begins in a valid
location.
A 16-row-deep RAM accompanies the ACU to store values needed for storing absolute
addresses of data RAM sections that are required during program execution. It also stores other
values that the ACU might need access to, such as values for freg. During run time, the
preferred way to place data into the ACU RAM is through system software intervention.
Use of the ACU command is defined as follows:
acu(instruction_A, instruction_B)
The two different instructions, instruction_A and instruction_B, represent members of the ACU
instruction set that control the addresses for two data RAMs independently. The following table
shows a comprehensive list of the ACU instruction set.
Instruction
Description
hold
Puts the registered output address value on the output unchanged.
incr
Increases the registered output address value (reg) by one and puts it on the output.
decr
Decreases the registered output address value (reg) by one and puts it on the output.
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PSoC® Creator™ Component Datasheet
Instruction
Digital Filter Block (DFB) Assembler
Description
read
Gets the specified byte from the ACU RAM, loads it to the output address register, and puts the
value on the output. (See the addr command.)
write
Puts the registered output address value into the specified ACU RAM row. (See the addr
command.)
loadf
Loads freg with the value from the specified ACU RAM. The ACU output value remains the same as
the previous cycle. (See the addr command for information about ACU RAM addressing.)
loadl
Loads lreg with the value from the specified ACU RAM. The ACU output value remains the same as
the previous cycle. (See the addr command for information about ACU RAM addressing.)
loadm
Loads mreg with value of the specified ACU RAM. The ACU output value remains the same as the
previous cycle. (See the addr command for information about ACU RAM addressing.)
writel
Puts the value of lreg on the output and then writes the output to the specified ACU RAM location.
(See the addr command.)
setmod
Enables modulus arithmetic in the ACU. Modulus arithmetic is on by default.
unsetmod
Disables modulus arithmetic in the ACU. Modulus arithmetic is on by default.
clear
Sets the registered output value (reg) to zero.
addf
Increases the registered output address value (reg) by the value in register freg. When modulus
arithmetic is disabled and the ACU output is outside the region defined between lreg and mreg, do
not use this command.
subf
Decreases the registered output address value (reg) by the value in register freg. When modulus
arithmetic is disabled and the ACU output is outside the region defined between lreg and mreg, do
not use this command.
writem
Puts the value of mreg on the output and writes the output to the specified ACU RAM location. (See
the addr command.)
writef
Puts the value of freg on the output and writes the output to the specified ACU RAM location. (See
the addr command.)
addr
The addr command takes a value between zero and fifteen as an argument. It is used in several
different ways. Be careful to write programs in such a way that commands within the same
instruction do not require more than one access to the addr value. Multiple access of addr does
not generate an error, but a warning, if you do not redefine the addr value.
The addr command can act in five different ways. You cannot choose more than one at a time.


To access a location in ACU RAM. You can specify a single ACU RAM location to be
accessed by both the ACUs. (Both sides must access the same row of ACU RAM. Side A
cannot read from row 1 while B reads from row 14.)
To specify which input and output channels to write to or read from. Channel 1 is selected for
odd addr values (when addr’s LSB is 1) and Channel 2 is selected for even addr values. See
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Digital Filter Block (DFB) Assembler
PSoC® Creator™ Component Datasheet
the dmux section for more information about input channels and input staging registers, and
the write section for information on output staging registers.



To provide a value to write semaphores and enable and disable semaphores as jump
conditions. The addr value is automatically set by the 3-bit fields specified in the semaphore
commands. (See the ALU section.)
Enabling and disabling the saturation and rounding flags and clearing the saturation detection
flag hides the explicit definition of the addr value from you and defines it automatically. (See
the ALU section.)
Enabling and disabling the global interrupts as jump conditions defines the addr value using
the 2-bit field in the englobal command. (See the ALU section.). If the addr command is
called as addr(1), both the side A and side B ACU will access ACU RAM row 1.
If the command causes a bus read, bus data is read from staging register 1. If the command
causes a bus write, data is written to output staging register 1.
This is an example of the problem with having multiple accesses to the value of the addr
command. When the addr value is defined once, all access to it must use the same value, or
the customizer will return an error. The explicit definition of addr prevents the use of the
semaphore, global jump condition enables, and saturation and rounding register commands.
dmux
Figure 4. Datapath
Six bits in the control store RAM (cstore) output word control datapath muxing and specify the
route data takes through the datapath. The MAC, ALU, and output shifter have three levels of
muxing for both side A and side B. Similar to the ACU, dmux takes an argument for side A and
side B.
dmux(instruction_A, instruction_B)
When mux1 (see Figure 4) is set to allow access to the bus, it consumes whatever value is
waiting in the input register. Unless the system is completely deterministic, code should wait for
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PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
the controller to signal the availability of a value using a wait state that loops until the input
channel ready jump condition is valid.
The following table shows a comprehensive list of the dmux instruction set.
Instruction
Description
ba
Bus to ALU. mux1 passes the bus data to the data RAM. mux2 circumvents the data RAM and
passes mux1 data directly to the MAC and mux3. mux3 circumvents the MAC and passes mux2
directly to the ALU input. The bus data comes from one of the two staging registers based on an
addr declaration of either 0 or 1.
sa
Shifter to ALU. mux1 passes the shifter output data to the data RAM. mux2 circumvents the data
RAM and passes mux1 data directly to the MAC and mux3. mux3 circumvents the MAC and passes
mux2 directly to the ALU input.
bra
Bus to RAM, RAM to ALU.
mux1 passes the bus data to the data RAM.
mux2 passes data from the data RAM to the MAC and mux3.
mux3 circumvents the MAC and passes mux2 directly to the ALU input. T The bus data comes from
one of the two staging registers based on an addr declaration of either 0 or 1.
sra
Shifter to RAM, RAM to ALU. mux1 passes the shifter output data to the data RAM. mux2 passes
data from the data RAM to the MAC and mux3. mux3 circumvents the MAC and passes mux2
directly to the ALU input.
bm
Bus to MAC, MAC to ALU. mux1 passes the bus data to the data RAM. mux2 circumvents the data
RAM and passes mux1 data directly to the MAC and mux3. mux3 passes the MAC output to the
ALU input. The bus data comes from one of the two staging registers based on an addr declaration
of either 0 or 1.
sm
Shifter to MAC, MAC to ALU. mux1 passes the shifter output data to the data RAM. mux2
circumvents the data RAM and passes mux1 data directly to the MAC and mux3. mux3 passes the
MAC output to the ALU input.
brm
Bus to RAM, to MAC. mux1 passes the bus data to the data RAM. mux2 passes the data from the
data RAM to the MAC and mux3. mux3 passes the MAC output to the ALU input. The bus data
comes from one of the two staging registers. Register choice is based on an addr declaration of
either 0 or 1.
srm
Shifter to RAM to MAC. mux1 passes the shifter output data to the data RAM. mux2 passes the
data from the data RAM to the MAC and mux3. mux3 passes the MAC output to the ALU input.
ALU
The ALU provides data control on the output end of the datapath. In addition to generic functions
such as add and subtract, the ALU can set flags signaling that specific conditions for jumps
between states have been met. The alu command includes five special instructions that require a
bit field of three bits as input data. The ALU’s output feeds directly into the shift register.
There are two format options for an “alu” command:
alu(instruction) or alu(special_instruction, 3-bit_field)
The following table shows a comprehensive list of the alu instruction set.
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Digital Filter Block (DFB) Assembler
Instruction
Description
set0
Sets the ALU output to zero.
set1
Sets the ALU output to an integer value of one. That is, the LSB is one, all others are zero.
seta
Passes input A to the output.
setb
Passes input B to the output.
nega
Negates A and passes it to the output.
negb
Negates B and passes it to the output.
passrama
Passes RAM A’s current location value to the output.
passramb
Passes RAM B’s current location value to the output.
add
Evaluates and places ‘A + B’ on the ALU output.
tdeca
Evaluates and places ‘A – 1’ on the ALU output. A value of zero sets threshold detection. The
design includes this command as a way to wait a set amount of time while a value counts down to
zero. It is intended for use in a low-power wait mode.
suba
Evaluates and places ‘B – A’ on the ALU output.
subb
Evaluates and places ‘A – B’ on the ALU output.
absa
Evaluates and places ‘|A|’ on the ALU output.
absb
Evaluates and places ‘|B|’ on the ALU output.
addabsa
Evaluates and places ‘|A| + B’ on the ALU output.
addabsb
Evaluates and places ‘A + |B|’ on the ALU output.
hold
Maintains the ALU output value from the previous cycle.
englobals
Enables or disables the two global interrupts and the saturation detection flag as jump conditions for
state changes. This is based on the 3-bit field following the command and a separating comma. The
global interrupts are inputs to the DFB. The saturation detection flag is set when a wraparound
would otherwise happen if the saturation logic holds the value at the maximum or minimum
datapath value.
This command sets the value for addr automatically, based on the entry to the bit field. englobals
shares an ALU opcode with ensatrnd. The behavior of these commands is determined in hardware
by the value of the addr opcode. The customizer generates errors if the program tries to define the
addr command with different values. The following would set global interrupt 2 and saturation to be
disabled as a jump condition and global interrupt 1 to be enabled.
alu(englobals, 001)
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PSoC® Creator™ Component Datasheet
Instruction
ensatrnd
Digital Filter Block (DFB) Assembler
Description
Enables and disables saturation and rounding in the datapath by writing to the saturation and
rounding registers. The value written to the saturation and rounding register it is taken from the last
two bits of the 3-bit field following both the command and a separating comma. The first bit of the 3bit field strobes the saturation detection flag and clears it. This command uses and sets the value
for addr automatically. Additionally this command shares an opcode with englobals; the behaviors
of these two commands are determined in hardware by the value of the addr opcode. The
customizer generates errors if the program tries to define the addr command with different values.
The following ALU command would turn on rounding, turn off saturation and clear the saturation
detection flag if it is set.
alu(ensatrnd, 001)
ensem
Enables specified semaphores as jump conditions based on the 3-bit field following the command
and a separating comma. This command uses and sets the value for addr automatically, based on
the 3-bit field. Therefore, the customizer generates errors if the program tries to define the addr
command with different values using this instruction. This instruction has a two cycle delay before
the change becomes a valid jump condition. While using the semaphore as a jump condition, the
condition “sem” can be used as a reminder to the programmer that a semaphore condition has
been set. If the program no longer wants the semaphore as a jump condition, it must clear the
enable flags with a call of the command with every bit in the field set to zero.
alu(ensem, 000)
setsem
Sets the semaphores masked with ones in the 3-bit field to 1. Do not use setsem in the first
instruction after reset or the semaphore will be repeatedly set. This command uses and sets the
value for addr automatically. The customizer generates errors if the program tries to define the addr
command with different values. The following sets semaphore 0 to true (1).
alu(setsem, 100)
clearsem
Clears the semaphores masked with ones in the 3-bit field. (that is, sets them to zero). This
command uses and sets the value for addr automatically. The customizer generates errors if the
program tries to define the addr command with different values. The following sets the value of
semaphore 0 to false (0).
alu(clearsem, 100)
tsuba
Evaluates and places ‘B – A’ on the output. Sets threshold detection.
tsubb
Evaluates and places ‘A – B’ on the output. Sets threshold detection.
taddabsa
Evaluates and places ‘|A| + B’ on the output. Sets threshold detection.
taddabsb
Evaluates and places ‘A + |B|’ on the output. Sets threshold detection.
sqlcmp
Loads a value from mux3 of side A into the compare register to be used as a cutoff in squelch
functions.
sqlcnt
Loads the lower 16 bits of mux3 on side A into the 16-bit count register. This value is decremented
every time a squelch command is called, if the current value at the output does not meet the
threshold set by the squelch compare register. It is reset to its original value every time the
threshold is met.
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Digital Filter Block (DFB) Assembler
Instruction
sqa
Description
Takes the value on mux3 of side A and compares it to the value in the squelch compare register. If
the current value is greater than the value of the compare register, the current value is passed to
the output and the squelch count register is reset to its original value.
If the current value is less than the compare register value, the command checks the squelch
counter. If it is not at zero, the value is decremented and the current value on mux3 of side A is
passed to the output. If the value of the count register is zero, zero is passed to the output.
sqb
Takes the value on mux3 of side B and compares it to the value in the squelch compare register. If
the current value is greater than the value of the compare register, the current value is passed to
the output and the squelch count register is reset to its original value.
If the current value is less than the compare register value, the command checks the squelch
counter. If it is not at zero, the value is decremented and the current value on mux3 of side B is
passed to the output. If the value of the count register is zero, zero is passed to the output.
MAC
Multiply and Accumulate unit. Contains the hardware to multiply two fixed-point numbers and
then add them to a previous value. ‘(A × B) + C’
There are four members in the MAC instruction set and they operate as follows:
mac(instruction)
The following table shows a comprehensive list of the MAC instruction set.
Instruction
Description
loadalu
Adds the previous ALU output (from the shifter) to the product and starts a new accumulation.
clra
Clears the accumulator and stores the current product.
hold
Holds the value in the accumulator from the previous cycle. No multiply.
macc
Multiply and Accumulate. Multiplies the values on mux2 of side A and side B. Adds the product to
the current value of the accumulator.
shift
The shift command allows you to scale the ALU output. A valid shift command takes two
arguments, direction and magnitude, and evaluates them to produce the correct opcode. Valid
directions instructions are ‘right’, ‘left’, ‘r’, and ‘l’. A shift to the right allows magnitudes of 1, 2, 3,
4, and 8, while a shift to the left allows only the values 1 and 2. The output of the ALU is passed
through the shifter and back out to the start of the datapath regardless of whether a shift occurs.
shift(direction, magnitude)
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Digital Filter Block (DFB) Assembler
The following table shows a comprehensive list of the shift instruction set.
Instruction
Description
right, r
Equivalent instructions specifying the direction to shift.
left, l
Equivalent instructions specifying the direction to shift.
write
A valid write command has zero to three arguments. A value is written for each argument. You
can choose to write the value on mux1 of either side to the data RAM of the same side, or to
write the current shifter output value to a staging register on the output. Check for the various
pipeline delays in the DFB datapath before using the write instruction.
There are system level implications if the first instruction following a reset contains a bus write
command. The assembler prevents writes in the first instruction to prevent unintended problems.
Each of the following is a valid write command.



write(da, db, bus)
write(da, db)
write(db)
The following table shows a comprehensive list of the write instruction set.
Instruction
Description
da
Writes the mux1A value to the specified data_a Ram location after the ACU instruction for the line,
No delay in write execution.
db
Writes the mux1B value to the specified data_b Ram location after the ACU instruction for the line,
No delay in write execution.
abus
Write shifter output to the bus’ holding register A. Holding register A is selected based on an addr
definition of 1 (see the addr section).
bbus
Write shifter output to the bus’ holding register B. Holding register B is selected based on an addr
definition of 0 (see the addr section).
bus
Write shifter output to the bus’ holding register. There are two output holding registers available.
The register is selected based on an addr definition of either 1 or 0 (see the addr section). This
instruction has been left for compatibility; do not use the bus instruction in new projects. Using the
instruction generates a warning: “Potential addr() conflict attempting write(bus). Avoid this warning
by using channel-specific bus write commands.”
Jump Instructions
A jump instruction allows the code to change its location to a different subroutine. Jump
instructions have a general form of:
JumpType(conditions, Target Routine)
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Digital Filter Block (DFB) Assembler
where “conditions” is an ordered list of any of the enables available to restrict or allow jumps.
The literals associated with these flags are described immediately following the description of the
jump options. Be careful with jump instruction placement because some conditions require two
cycles instead of one before the controller can use them as a valid jump condition. Additionally, a
jump instruction cannot be used in the first instruction after a reset because the first state must
be two instructions deep to set up pipelining.
The Diagrams of Jump Instruction section contains a diagram of jump conditions.
The following table shows a comprehensive list of the jump instruction set.
Instruction
jmp
Description
Jump” is similar to a standard “goto” instruction. If conditions are true, the code jumps to the target
routine. If not, it falls through to next state numerically. When not in a loop, the fjlim (false jump limit)
value is set to the max cstore location.
jmp(eob, sign,…, Target State)
jmpl
“Jump Loop” sets the current block of code to be a loop. It is a two-way branch with the target
routine as one branch when conditions are met, and the start of the current code block as the other
branch when conditions are not met.
When in a loop the following occurs:

Bit 23 of the CFSM is set high.

False jump address (FJADDR) is defined as the start of the current code block, which is the
control store address of the label. (The label is not stored in the control store; the label
references the first command of the block of code.)

False jump limit (FJLIM) is set to the current CLC location, which is the end of the code block

(Same for all jumps) The target routine’s label is used to provide the jump address (JADDR)
and the CFSM RAM location of the next state on true conditions.
Commands execute until the eob is detected. The program evaluates the condition and if it is false,
set the program counter to FJADDR, restarting the block. If the condition is true, the program
counter is set to JADDR and the state is updated to NextStateOnTrue. The format is identical to the
jmp command.
jmpl(conditions, Target State)
jmpsl
“Jump to Subroutine Loop” allows a jump to a subroutine block of code that is designated to be a
loop. The effect jmpsl has on the current block of code is identical to the jmp command. If
conditions are met, the code jumps to the specified subroutine, otherwise it falls through to the next
state in code execution. However, jmpsl affects the subroutine’s state. Each time a subroutine is
referenced, a copy of that subroutine is created as a state for the CFSM and properties for the new
state are set. In the case of jmpsl, the created state is designated to be a loop and to have a return
state of the next state in the code space. (The current state is the state that ends with the jmpsl
command.) For more information about states and subroutines, see the jmpret entry in this table.
jmpsl(conditions, Target Subroutine)
jmpslr
“Jump to Subroutine Loop with Return state” is identical to jmpsl in every way except that the return
state is specified instead of defaulting to the state following the current state.
jmpslr(conditions,…, Target Subroutine, Return State)
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PSoC® Creator™ Component Datasheet
Instruction
Digital Filter Block (DFB) Assembler
Description
jmps and
jmpsr
These two are clones of jmpsl and jmpslr except that the created subroutine state is not a loop.
Because of this, only the eob condition is specified in the jmpret statement.
jmpret
Subroutines are accessed only through one of the jump-to-subroutine commands. Subroutines
differ from standard states because that their properties are determined by the state that calls them,
instead of the jump condition at the end of the state. If a state calls a subroutine with the jump
command “jmpslr(eob, sub1, anotherState), it defines the subroutine to be a loop and have a next
state of “anotherState.”
Subroutines are terminated with a jump instruction of the type jmpret (jump return), which provides
the subroutine with its own set of jump conditions for loop termination (if the subroutine is called as
a loop). Subroutines cannot call other subroutines because the jmpret command does not provide
the necessary exit information to the sub-subroutine state.
The jmpret command is used as a jmp command, but with no target state specified.
jmpret(condition,condition,..)
Jump Conditions
Conditions enable or prevent state changes in code. The following conditions are, in essence,
enable flags for hardware. When a condition is listed, it requires the signal complementing the
enable to be true, in order for the jump to proceed.
Note Datapath conditions have a two-cycle delay. That is, they must be true two cycles before
the jump to recognize the condition as true.
The following table shows a comprehensive list of jump conditions.
Instruction
Description
eob
End Of Block. A condition for a jump, which is always met because a jump instruction signifies the
end of the block. eob only needs to be specified when an unconditional jump occurs. This is
because of a software restriction, not a hardware restriction.
dpsign
A jump based on the MSB of the ALU output. Asserted when the ALU output is negative. Datapath
conditions require a two-cycle delay to meet a jump condition.
dpthresh
Datapath Threshold. Asserted when the ALU detects a sign change. The ALU asserts dpthresh only
when the program uses ALU threshold detection operands (tsuba, tsubb, taddabsa, …). Datapath
conditions require a two-cycle delay to meet a jump condition.
dpeq
Datapath Equity. Asserted when the ALU hardware detects an output value of zero. The ALU
asserts dpeq only when the program uses ALU threshold detection operands (tsuba, tsubb,
taddabsa, …). Datapath conditions require a two-cycle delay to meet a jump condition.
acuaeq
ACU A Equals. Asserted when ACU A detects a wraparound condition. This can be either zero or
the maximum data RAM location if modulus arithmetic is disabled or the max and min modulo
counter limit when it is enabled. Datapath conditions require a one-cycle delay to meet a jump
condition.
acubeq
ACU B Equals. Asserted when ACU B detects a wraparound condition. This can be either zero or
the modulo counter limit. Datapath conditions require a one-cycle delay to meet a jump condition.
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Digital Filter Block (DFB) Assembler
Instruction
Description
in1
Channel 1 Input Register Value Ready signal. When it is asserted, a new input cycle is available for
consumption. It remains asserted until cleared by a bus read. Datapath conditions require a onecycle delay to meet a jump condition.
in2
Channel 2 Input Register Value Ready signal. When it is asserted, a new input cycle is available for
consumption. It remains asserted until cleared by a bus read. Datapath conditions require a onecycle delay to meet a jump condition.
sem
The sem condition has no effect on the opcodes. It improves code clarity and reminds the
programmer that a semaphore is currently a jump condition. (See the ALU section for details.)
globals
The globals condition has no effect on the opcodes. It improves code clarity reminds the
programmer that a global input is currently a jump condition. (See the ALU section for details.)
sat
The “sat” condition has no effect on the opcodes. It improves code clarity and reminds the
programmer that a saturation event is currently required to enable a jump. (See the ALU section for
details.)
DMUX Commands
Code
Name
Function Mux 1
Function Mux 2
Function Mux 3
0
ba
Bus register
Bus register
Bus register
1
sa
Previous shifter output
Previous shifter output
Previous shifter output
2
bra
Bus register
Current RAM value
Current RAM value
3
sra
Previous shifter output
Current RAM value
Current RAM value
4
bm
Bus register
Bus register
MAC accumulator
5
sm
Previous shifter output
Previous shifter output
MAC accumulator
6
brm
Bus register
Current RAM value
MAC accumulator
7
srm
Previous shifter output
Current RAM value
MAC accumulator
MAC Commands
Code
Name
Function
0
loadalu
Adds the ALU value to the product and starts a new accumulation.
1
clra
Clears the accumulator. Loads it with the current product.
2
hold
Holds the accumulator, no multiply (no power in mult).
3
macc
Standard operation – multiply and accumulate with the previous values
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Digital Filter Block (DFB) Assembler
ACU Commands
Code
Name
Function
0
hold
Puts reg on the output.
1
incr
Puts reg + 1 on the output, writes to reg.
2
decr
Puts reg – 1 on the output, writes to reg.
3
read
Loads reg from ACU RAM, puts the value on the output.
4
write
Puts reg into the specified ACU RAM row.
5
loadf
Loads freg from ACU RAM, puts reg on the output.
6
loadl
Loads lreg from ACU RAM, puts reg on the output.
7
loadm
Loads mreg from ACU RAM, puts reg on the output
8
writel
Puts lreg on the output, writes to ACU RAM.
9
setmod
Sets arithmetic to modulo mreg.
10
unsetmod
Sets arithmetic to wraparound.
11
clear
Sets reg to 0, put 0 on the output.
12
addf
Adds reg to freg, puts the result on the output, stores it in reg.
13
subf
Subtracts freg from reg, puts the result on the output, stores it in reg.
14
writem
Puts mreg on the output, writes to the ACU RAM.
15
writef
Puts freg on the output, writes to the ACU RAM.
ALU Commands
Code
Name
Function
0
set0
Sets the ALU output to 0.
1
set1
Sets the ALU output to 1.
2
seta
Passes A to the ALU output.
3
setb
Passes B to the ALU output.
4
nega
Sets the ALU output to –A.
5
negb
Sets the ALU output to –B.
6
passrama
Passes the RAM A output directly to the ALU output.
7
passramb
Passes the RAM B output directly to the ALU output.
8
add
Adds A and B and puts the result on the ALU output.
9
tdeca
Puts A – 1 on the ALU output, sets threshold detection.
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PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
Code
Name
Function
10
suba
Puts B – A on the ALU output.
11
subb
Puts A – B on the ALU output.
12
absa
Puts |A| on the ALU output.
13
absb
Puts |B| on the ALU output.
14
addabsa
Puts |A| + B on the ALU output.
15
addabsb
Puts A + |B| on the ALU output.
16
hold
Holds the ALU output from the previous cycle.
17
englobals
Enables global and saturation jump conditions using a three-bit field
to specify which events are active jump conditions.
17
ensatrnd
Writes to the saturation and rounding enable registers using a threebit field to enable and disable them.
18
ensem
Enables semaphores as jump conditions using a three-bit field to
specify which are active.
19
setsem
Sets the semaphores high using the three-bit mask.
20
clearsem
Sets the semaphores low using mask, addr[2:0].
21
tsuba
Puts B – A on the ALU output, sets threshold detection.
22
tsubb
Puts A – B on the ALU output, sets threshold detection.
23
taddabsa
Put |A| + B on the ALU output, set threshold detection
24
taddabsb
Puts A + |B| on the ALU output, sets threshold detection
25
sqlcmp
Loads the squelch comparison register with a value from side A,
passes side B.
26
sqlcnt
Loads the squelch count register with a value from side A, passes
side B.
27
sqa
Squelch side A. If the value is above the threshold, passes it. If the
value is below the threshold and the squelch count register is zero,
passes zero.
28
sqb
Squelch side B. If the value is above the threshold, pass it. If the
value is below the threshold and the squelch count register is zero,
passes zero.
29-31
undefined
Undefined opcodes
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PSoC® Creator™ Component Datasheet
Digital Filter Block (DFB) Assembler
Diagrams of Jump Instruction
jmps
jmp
True
State 0
jmp(cond, State 2)
State 0
Cond
State 2
jmps(cond, Sub 1)
True
False
False
Cond
Cond
Cond
State 1
State 2
State 1
jmpslr
jmpsl
State 0
True
jmpsl(cond, Sub 1)
Cond
True
State 0
Cond
jmpslr(cond, Sub 1, State 2)
False
False
Cond
Cond
Sub 1
State 1
False
Return
Cond
True
Return
State 1
Sub 1
Return
Cond
True
State 2
Cond
jmpl
Return
Cond
jmpsr
State 0
jmpsr(cond, Sub 1, State 2)
State 0 jmpl(cond,
State 1)
True
Cond
False
False
Cond
Sub1
True
Cond
False
Cond
State1
State 1
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State2
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Digital Filter Block (DFB) Assembler
PSoC® Creator™ Component Datasheet
Component Changes
This section lists the major changes in the component from the previous version.
Version
Description of Changes
1.10.b
Minor datasheet edit.
1.10.a
Minor edits and updates to datasheet
1.10
Updated DC and AC Electrical Characteristics
section.
Reason for Changes / Impact
© Cypress Semiconductor Corporation, 2012-2015. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the
use of any circuitry other than circuitry embodied in a Cypress product. Nor does it convey or imply any license under patent or other rights. Cypress products are not warranted nor intended to
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PSoC® and CapSense® are registered trademarks, and SmartSense™, PSoC Creator™, and Programmable System-on-Chip™ are trademarks of Cypress Semiconductor Corp. All other
trademarks or registered trademarks referenced herein are property of the respective corporations.
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Cypress does not assume any liability arising out of the application or use of any product or circuit described herein. Cypress does not authorize its products for use as critical components in lifesupport systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress’ product in a life-support systems application
implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges.
Use may be limited by and subject to the applicable Cypress software license agreement.
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