Digital Core Design

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D68HC11E

8-bit Microcontrollers Family

The D68HC11E is synthesisable SOFT Microcontroller IP Core, fully compatible with the Motorola 68HC11E industry standard. It can be used as a direct replacement for:

  • 68HC11E Microcontrollers

    and older 68HC11E versions:
  • 68HC11A and
  • 68HC11D

In the standard configuration, the core  has integrated, on-chip, major peripheral functions. An asynchronous serial communications interface (SCI) and separate synchronous serial peripheral interface (SPI), are included. The main 16-bit, free-running timer system, contains input capture and output-compare lines and a real-time interrupt function. An 8-bit pulse accumulator subsystem, can count external events or measure external periods. Self-monitoring, on-chip circuitry, is included, to protect the D68HC11E, against system errors. The Computer Operating Properly (COP) watchdog system, protects against software failures. An illegal opcode detection circuit, provides a non-maskable interrupt, if illegal opcode is detected. Two software-controlled power-saving modes, WAIT and STOP, are available to conserve additional power. These modes make the D68HC11E IP Core especially attractive, for automotive and battery-driven applications.

The D68HC11E Microcontroller Core can be equipped with the ADC Cotroller, allowing use of external ADC Controller, with standard ADC software. The ADC Controller, makes external ADC's visible as internal ADC's in original 68HC11E Microcontrollers.

The D68HC11 has a built-in real time hardware on chip debugger - DoCDTM, allowing easy software debugging and validation. The D68HC11E is fully customizable - it is delivered in the exact configuration, to meet users requirements. There is no need to pay extra, for not used features and wasted silicon. It includes fully automated testbench with complete set of tests allowing easy package validation, at each stage of SoC design flow.

Each of the DCD's D68HC11E Core, has built in support for DCD Hardware Debug System, called DoCDTM. It is a real-time hardware debugger which provides debugging capability of a whole System on Chip (SoC).

Unlike other on-chip debuggers, the DoCDTM provides a non-intrusive debugging of running application. It can halt, run, step into or skip an instruction, read/write any contents of microcontroller, including all registers, SFRs, including user defined peripherals, data and program memories. More details about DCD on Chip Debugger


Family summary

Family IP Core Architecture
type
Memory space DoCDTM UART (SCI) SPI M/S IO Ports Watchdog
Timer
Timer Compare / Capture Pulse
accumulator
READY
pin
Chip Selects Gatecount
HC05, HC08 DF6805 fast 64k + + - 4 + 1 2/2 - + - 7000
- DF6808 fast 64k + + - 4 + 1 2/2 - + - 8300
- D68HC05 legacy 64k + + + 4 + 1 1/1 - - - -
- D68HC08 legacy 64K + + + 4 + 1 2/1 - - - 10000
HC11 DF6811E fast 64k + + + 5 + 1 5/4 + + - 12000
- DF6811F fast 64k + + + 7 + 1 5/4 + + - 14000
- DF6811K fast 1M + + + 10 + 3 13/6 + + - 21000
- D68HC11E legacy 64k + + + 5 + 1 5/4 + - - 13000
- D68HC11K legacy 1M + + 1 10 + 3 13/6 + - 4 21000
- D68HC11F legacy 64k + + + 7 + 1 5/4 - - 4 13500
6802, 6803 DF6802 fast 64k + - - - - - - - - - -
- DF6803 fast 64k + + + 4 - 1 + - - - -
- D6802 legacy 64k + - - - - - - - - - 3600
- D6803 legacy 64k + + + 4 - 1 + - - - 6000

The main features of each D68XX and DF68XX family member, have been summarized in the table above. It gives a brief member characteristic, helping you to select the most suitable IP Core for your application. You can specify your own peripheral set (including listed above and the others) and request the core modifications.

Performance

Each core has been tested in variety of FPGA and ASIC technologies. Its implementation's results are summarized below.

Implementation Speed
grade
Utilized Area
[Slices]
Frequency
[MHz]
SPARTAN-IIE -7 2049 35
SPARTAN-III -5 2047 47
SPARTAN-IIIE -5 2047 47
VIRTEX-II -6 2047 67
VIRTEX-IV -12 2041 92

Implementation results of the D68HC11E in XILINX devices. All features are included.

Implementation Speed
grade
Utilized Area
[LC]
Frequency
[MHz]
CYCLONE -6 3639 54
CYCLONE II -6 3640 52
CYCLONE III -6 3640 52
STRATIX -5 3645 56
STRATIX II -3 2433 88
STRATIX III -2 2431 107
STRATIX IV -2 2508 141

D68HC11E implementation results for ALTERA devices. 


Implementation Speed
grade
Utilized Area
[Slices]
Frequency
[MHz]
XP - 2074 46
XP2 - 2074 47
MachXO2 - 1636 34

D68HC11E implementation results for LATTICE devices. 

Implementation Speed
grade
Utilized Area
[Tiles]
Frequency
[MHz]
Axcelerator -2 5098 39
ProAsic3 -2 7273 31
ProAsic3E -2 7273 30
Fusion -2 7265 36

Implementation results of the D68HC11E in ACTEL devices.


CPU Features


Symbol

 clk
 rst
 cmf
 porta
 portb
 portc
 portd
 porte (7:0)
 stra_as
strb_rw 
 moda_lir
 modb
 xirq
 irq
 docddatai
 clkdocd
docddatao 
docdclk 
 adcdatai
adcdatao 
adcclock 
adccs 
 esi
eso 
esck 
ecs 

Pins description

PinTypeDescription
clkinputGlobal clock
rstinputGlobal reset
cmfinputClock monitor fail reset
portainputBidirectional Port A, shared with Timer Output Compare and Input Capture functions
portbinputBidirectional Port B, shared with high address byte in Expanded mode
portcinputBidirectional Port C, shared with Low address Byte and Data bus. (Demultiplexed Address/Data bus is also possible)
portdinputBidirectional Port D, shared with SCi and SPI functions.
porte (7:0)input8 bit input port, typically shared with internal ADC
stra_asinputStrobe A, shared with AS (Address Strobe) in expanded mode
moda_lirinputMODA pin input shared with LIR output
modbinputMode B input
xirqinputNon-maskable interrupt request
irqinputMaskable interrupt request
docddataiinputDoCDTM serial data input
clkdocdinputClock signal to DoCDTM On chip Debugger module. This separate clock line allow DoCDTM to operate during the SLEEP mode (major clock CLK is stopped).
adcdataiinputSerial ADC data input
esiinputSerial Data input - connected to data output pin on EEPROM memory
strb_rwoutputStrobe B shared with R/W in Expanded Mode
eoutputE Clock output
docddataooutputDoCDTM serial data output
docdclkoutputDoCDTM serial data clock line
adcdataooutputSerial ADC data output
adcclockoutputSerial clock to ADC devices
adccsoutputSerial ADC chip select line
esooutputSerial data output - connected to data input on EEPROM Memory
esckoutputEEPROM SPI Clock line
ecsoutputEEPROM Chip Select

Block Diagram

BUSCTRLBus Controller - manages data exchange between CPU and several Internal and External Memories
SPIIt is a fully configurable master/slave Serial Peripheral Interface, which allows user to configure polarity and phase of Serial Clock Signal (SCK). It enables the microcontroller, to communicate with serial peripheral devices. It is also capable of interprocessor communications, in a multi-master system. The Serial Clock Line (SCK) synchronizes shifting and sampling of the information, on the two independent serial data lines. SPI data are simultaneously transmitted and received. SPI system is flexible enough, to interface directly with numerous standard product peripherals, from several manufacturers. Data rates are as high, as CLK/8. Clock control logic allows a selection of clock polarity and a choice of two fundamentally different clocking protocols, to accommodate most available synchronous serial peripheral devices. When the SPI is configured as a master, software selects one of four different bit rates for the serial clock. Error-detection logic is included, to support interprocessor communications. A write-collision detector indicates, when an attempt is made to write data to the serial shift register, while a transfer is in progress. A multiple-master mode-fault detector, automatically disables SPI output drivers, if more than one SPI devices simultaneously attempt to become a bus master.
IOPortsGeneral Purpose I/O Ports, when enabled, the I/O Ports are shared with particular on chip peripherals: SCI, SPI, TIMER.
porta
portb
portc
portd
porte (7:0)
strb_rw
stra_as
SCIThe SCI is a full-duplex UART type asynchronous system, using standard, non return to zero (NRZ) format : 1 start bit, 8 or 9 data bits and a 1 stop bit. The Core resynchronizes the receiver bit clock on all one to zero transitions in the bit stream. Therefore, the differences in baud rate, between the sending device and the SCI, are not as likely to cause reception errors. Three logic samples are taken near the middle of data bit time and major logic decides the sense for the bit. For the start and stop bits, seven logic samples are taken. Even if noise causes one of these samples to be incorrect, the bit will still be received correctly. The receiver also has the ability to enter a temporary standby mode (called receiver wakeup), to ignore messages intended for a different receiver. The logic automatically wakes up the receiver, in time to see the first character of the next message. This wakeup feature greatly reduces CPU overhead in multidrop SCI networks. The SCI transmitter can produce queued characters of idle (whole characters of all logic 1) and break (whole characters of all logic 0). In addition to the usual Transmit Data Register Empty (TDRE) status flag, this SCI also provides a Transmit Complete (TC) indication, which can be used in applications with a modem.
PULSEACCAThis system is based on an 8-bit counter and can be configured to operate as a simple event counter or as a tool for gated time accumulation. Unlike the main timer, the 8-bit pulse accumulator counter can be read or written at any time (the 16-bit counter in the main timer cannot be written). Control bits allow the user to configure and control the pulse accumulator subsystem. Two maskable interrupts are associated with the system, each having its own controls and interrupt vector. The PAI pin associated with the pulse accumulator, can be configured to act as a clock (event counting mode) or as a gate signal, to enable a free-running of E divided by 64 clock, to the 8-bit counter (gated time accumulation mode). The alternate functions of the PAI (Pulse Accumulator Input) pin, present some interesting application possibilities.
COPCOP Watchdog Timer
CTRLUNITPerforms the core synchronization and data flow control. This module manages execution of all instructions.
moda_lir
modb
e
Interrupt ControllerD68HC11 has implemented 17-level interrupt priority control. External interrupt pins are activated at low level (XIRQ, IRQ pins) or falling edge (IRQ pin). External interrupt requests by IRQ and XIRQ, are sampled each 1 system clock at the rising edge of CLK. The D68HC11 peripheral systems generate maskable interrupts, which are recognized only, if the global interrupt mask bit (I) in the CCR, is cleared. Maskable interrupts are prioritized according to default arrangement (look at the table below), established during reset. However, any source may be elevated to the highest maskable priority position, by using HPRIO register. When interrupt condition occurs, an interrupt status flag is set to indicate the condition.
xirq
irq
TIMERMain Timer system, including Compare, Capture and Real Time Interrupt logic. This timer system is based on a free-running, 16-bit counter, with a 4-stage programmable prescaler. A timer overflow function allows software, to extend the timing capability of the system, beyond the 16-bit range of the counter. Three independent input-capture functions are used to automatically record the time, when a selected transition is detected at a respective timer input pin. Five output-compare functions are included for generating output signals, or for timing software delays. Since the input-capture and output-compare functions may not be familiar to all users, these concepts are explained in more detail.
A programmable periodic interrupt circuit (RTI) is tapped off the main 16-bit timer counter. Software can select one of four rates for the RTI, which is most commonly used to pace the execution of software routines. The COP watchdog function is closely related to the main timer, in which the clock input to the COP system (clk*2^17) is tapped off the free-running counter chain.
The timer subsystem involves more registers and control bits, than any other subsystem on the MCU. Each of the three input-capture functions, has its own 16-bit time capture latch (input-capture register) and each of the five output-compare functions, has its own 16-bit compare register. All timer functions, including the timer overflow and RTI, have their own interrupt controls and separate interrupt vectors. Additional control bits permit the software, to control the edge(s), that trigger each input-capture function and the automatic actions, that result from output-compare functions. Although hardwired logic is included to automate many timer activities, this timer architecture is essentially a software-oriented system. This structure is easily adaptable to a very wide range of applications, although it is not as efficient as a dedicated hardware, for some specific timing applications.
DoCDTM DoCDTM Debug Unit is a real-time hardware debugger, which provides debugging capability of a whole SoC system. Unlike other on-chip debuggers, DoCDTM ensures non-intrusive debugging of running application. It can halt, run, step into or skip an instruction, read/write any contents of microcontroller, including all registers, internal and external program memories, all SFRs, including user defined peripherals. Hardware breakpoints can be set and controlled on program memory, internal and external data memories, as well as on SFRs. Hardware breakpoint is executed, if any write/read occurs at particular address, with certain data pattern or without pattern. The DoCDTM system includes three-wire interface and complete set of tools, to communicate and work with core in real time debugging. It is built as scalable unit and some features can be turned off, to save silicon and reduce power consumption. When debugger is not used, it is automatically switched to power save mode. Finally, when debug option is no longer used, whole debugger is turned off.
The separate DoCDTM clock line, allows debugger to operate in the SLEEP mode (major clock line CLK is stopped).
docddatai
docddatao
docdclk
clkdocd
ADC ControllerThe ADCCTRL used in D68HC11, provides communication between the internal ADC related registers and program running on D68HC11 and external ADC converter. Supports several Parallel and serial ADC.
adcdatai
adcdatao
adcclock
adccs
ALUArithmetic Logic Unit - performs the arithmetic and logic operations, during execution of an instruction. It contains accumulator (A, B), Condition Code Register (CCREG) and related logic, such as arithmetic unit, logic unit, multiplier and divider.
EEPROMCTRLExternal Serial EEPROM controller. This optional module, manages data exchange between D68HC11 and external EEPROM. During initialization, it copies contents of the whole external EEPROM, to internal EEPRAM (EEPROM Mirror implemented in standard parallel RAM). This module has several different options, therefore its details have been described in a separate document.
esi
eso
esck
ecs
clk
rst
cmf
Data bus Internal 8-bit data bus.
SFR data bus 8-bit Special Function Registers bus is used to inter-communication of all processors" peripherals. It allows easy management of system architecture.

Units

BUSCTRL
Bus Controller - manages data exchange between CPU and several Internal and External Memories
SPI
It is a fully configurable master/slave Serial Peripheral Interface, which allows user to configure polarity and phase of Serial Clock Signal (SCK). It enables the microcontroller, to communicate with serial peripheral devices. It is also capable of interprocessor communications, in a multi-master system. The Serial Clock Line (SCK) synchronizes shifting and sampling of the information, on the two independent serial data lines. SPI data are simultaneously transmitted and received. SPI system is flexible enough, to interface directly with numerous standard product peripherals, from several manufacturers. Data rates are as high, as CLK/8. Clock control logic allows a selection of clock polarity and a choice of two fundamentally different clocking protocols, to accommodate most available synchronous serial peripheral devices. When the SPI is configured as a master, software selects one of four different bit rates for the serial clock. Error-detection logic is included, to support interprocessor communications. A write-collision detector indicates, when an attempt is made to write data to the serial shift register, while a transfer is in progress. A multiple-master mode-fault detector, automatically disables SPI output drivers, if more than one SPI devices simultaneously attempt to become a bus master.
IOPorts
General Purpose I/O Ports, when enabled, the I/O Ports are shared with particular on chip peripherals: SCI, SPI, TIMER.

SCI
The SCI is a full-duplex UART type asynchronous system, using standard, non return to zero (NRZ) format : 1 start bit, 8 or 9 data bits and a 1 stop bit. The Core resynchronizes the receiver bit clock on all one to zero transitions in the bit stream. Therefore, the differences in baud rate, between the sending device and the SCI, are not as likely to cause reception errors. Three logic samples are taken near the middle of data bit time and major logic decides the sense for the bit. For the start and stop bits, seven logic samples are taken. Even if noise causes one of these samples to be incorrect, the bit will still be received correctly. The receiver also has the ability to enter a temporary standby mode (called receiver wakeup), to ignore messages intended for a different receiver. The logic automatically wakes up the receiver, in time to see the first character of the next message. This wakeup feature greatly reduces CPU overhead in multidrop SCI networks. The SCI transmitter can produce queued characters of idle (whole characters of all logic 1) and break (whole characters of all logic 0). In addition to the usual Transmit Data Register Empty (TDRE) status flag, this SCI also provides a Transmit Complete (TC) indication, which can be used in applications with a modem.
PULSEACCA
This system is based on an 8-bit counter and can be configured to operate as a simple event counter or as a tool for gated time accumulation. Unlike the main timer, the 8-bit pulse accumulator counter can be read or written at any time (the 16-bit counter in the main timer cannot be written). Control bits allow the user to configure and control the pulse accumulator subsystem. Two maskable interrupts are associated with the system, each having its own controls and interrupt vector. The PAI pin associated with the pulse accumulator, can be configured to act as a clock (event counting mode) or as a gate signal, to enable a free-running of E divided by 64 clock, to the 8-bit counter (gated time accumulation mode). The alternate functions of the PAI (Pulse Accumulator Input) pin, present some interesting application possibilities.
COP
COP Watchdog Timer

CTRLUNIT
Performs the core synchronization and data flow control. This module manages execution of all instructions.
Interrupt Controller
D68HC11 has implemented 17-level interrupt priority control. External interrupt pins are activated at low level (XIRQ, IRQ pins) or falling edge (IRQ pin). External interrupt requests by IRQ and XIRQ, are sampled each 1 system clock at the rising edge of CLK. The D68HC11 peripheral systems generate maskable interrupts, which are recognized only, if the global interrupt mask bit (I) in the CCR, is cleared. Maskable interrupts are prioritized according to default arrangement (look at the table below), established during reset. However, any source may be elevated to the highest maskable priority position, by using HPRIO register. When interrupt condition occurs, an interrupt status flag is set to indicate the condition.
TIMER
Main Timer system, including Compare, Capture and Real Time Interrupt logic. This timer system is based on a free-running, 16-bit counter, with a 4-stage programmable prescaler. A timer overflow function allows software, to extend the timing capability of the system, beyond the 16-bit range of the counter. Three independent input-capture functions are used to automatically record the time, when a selected transition is detected at a respective timer input pin. Five output-compare functions are included for generating output signals, or for timing software delays. Since the input-capture and output-compare functions may not be familiar to all users, these concepts are explained in more detail.
A programmable periodic interrupt circuit (RTI) is tapped off the main 16-bit timer counter. Software can select one of four rates for the RTI, which is most commonly used to pace the execution of software routines. The COP watchdog function is closely related to the main timer, in which the clock input to the COP system (clk*2^17) is tapped off the free-running counter chain.
The timer subsystem involves more registers and control bits, than any other subsystem on the MCU. Each of the three input-capture functions, has its own 16-bit time capture latch (input-capture register) and each of the five output-compare functions, has its own 16-bit compare register. All timer functions, including the timer overflow and RTI, have their own interrupt controls and separate interrupt vectors. Additional control bits permit the software, to control the edge(s), that trigger each input-capture function and the automatic actions, that result from output-compare functions. Although hardwired logic is included to automate many timer activities, this timer architecture is essentially a software-oriented system. This structure is easily adaptable to a very wide range of applications, although it is not as efficient as a dedicated hardware, for some specific timing applications.

DoCDTM
DoCDTM Debug Unit is a real-time hardware debugger, which provides debugging capability of a whole SoC system. Unlike other on-chip debuggers, DoCDTM ensures non-intrusive debugging of running application. It can halt, run, step into or skip an instruction, read/write any contents of microcontroller, including all registers, internal and external program memories, all SFRs, including user defined peripherals. Hardware breakpoints can be set and controlled on program memory, internal and external data memories, as well as on SFRs. Hardware breakpoint is executed, if any write/read occurs at particular address, with certain data pattern or without pattern. The DoCDTM system includes three-wire interface and complete set of tools, to communicate and work with core in real time debugging. It is built as scalable unit and some features can be turned off, to save silicon and reduce power consumption. When debugger is not used, it is automatically switched to power save mode. Finally, when debug option is no longer used, whole debugger is turned off.
The separate DoCDTM clock line, allows debugger to operate in the SLEEP mode (major clock line CLK is stopped).
ADC Controller
The ADCCTRL used in D68HC11, provides communication between the internal ADC related registers and program running on D68HC11 and external ADC converter. Supports several Parallel and serial ADC.
ALU
Arithmetic Logic Unit - performs the arithmetic and logic operations, during execution of an instruction. It contains accumulator (A, B), Condition Code Register (CCREG) and related logic, such as arithmetic unit, logic unit, multiplier and divider.

EEPROMCTRL
External Serial EEPROM controller. This optional module, manages data exchange between D68HC11 and external EEPROM. During initialization, it copies contents of the whole external EEPROM, to internal EEPRAM (EEPROM Mirror implemented in standard parallel RAM). This module has several different options, therefore its details have been described in a separate document.