The MC68HC11F1 is a high-performance member of the M68HC11 family of microcontroller units
(MCUs). High-speed expanded systems required the development of this chip with its extra input/output
(I/O) ports, an increase in static RAM (one Kbyte), internal chip-select functions, and a non-multiplexed
bus which reduces the need for external interface logic. The timer, serial I/O, and analog-to-digital (A/
D) converter enable functions similar to those found in the MC68HC11E9.
The MC68HC11FC0 is a low cost, high-speed derivative of the MC68HC11F1. It does not have
EEPROM or an analog-to-digital converter. The MC68HC11FC0 can operate at bus speeds as high as
six MHz.
This document provides a brief overview of the structure, features, control registers, packaging information and availability of the MC68HC11F1 and MC68HC11FC0. For detailed information on
M68HC11 subsystems, programming and the instruction set, refer to the
(M68HC11RM/AD).
M68HC11 Reference Manual
1.1 Features
• MC68HC11 CPU
• 512 Bytes of On-Chip Electrically Erasable Programmable ROM (EEPROM) with Block Protect
(MC68HC11F1 only)
• 1024 Bytes of On-Chip RAM (All Saved During Standby)
• Enhanced 16-Bit Timer System
— 3 Input Capture (IC) Functions
— 4 Output Compare (OC) Functions
— 4th IC or 5th OC (Software Selectable)
• On-Board Chip-Selects with Clock Stretching
• Real-Time Interrupt Circuit
• 8-Bit Pulse Accumulator
• Synchronous Serial Peripheral Interface (SPI)
• Asynchronous Nonreturn to Zero (NRZ) Serial Communication Interface (SCI)
The following devices all have 1024 bytes of RAM. In addition, the MC68HC11F1 devices have 512
bytes of EEPROM. None of the devices contain on-chip ROM.
Table 1 MC68HC11F1 Standard Device Ordering Information
VDD is the positive power input to the MCU, and VSS is ground.
RESET
This active-low input initializes the MCU to a known startup state. It also acts as an open-drain
output to indicate that an internal failure has been detected in either the clock monitor or the COP
watchdog circuits.
XTAL and EXTAL
These two pins provide the interface for either a crystal or a CMOS-compatible clock to drive the
internal clock circuitry. The frequency applied to these pins is four times the desired bus
frequency (E clock).
E
This pin provides an output for the E clock, the basic timing reference signal for the bus circuitry.
The address bus is active when E is low, and the data bus is active when E is high.
DS
The data strobe output is the inverted E clock. DS is present on the MC68HC11FC0 only.
WAIT
This input is used to stretch the bus cycle to accomodate slower devices. The MCU samples the
logic level at this pin on the rising edge of E clock. If it is high, the MCU holds the E clock high for
the next four EXTAL clock cycles. If it is low, the E clock responds normally, going low two
EXTAL cycles later. The WAIT pin is present on the MC68HC11FC0 only.
4XOUT
This pin provides a buffered oscillator signal to drive another M68HC11 MCU. The 4XOUT pin is
not present on the 64-pin QFP MC68HC11FC0 package.
IRQ
This active-low input provides a means of generating asynchronous, maskable interrupt requests
for the CPU.
XIRQ
This interrupt request input can be made non-maskable by clearing the X bit in the MCU’s
condition code register.
MODA/LIR and MODB/VSTBY
The logic level applied to the MODA and MODB pins at reset determines the MCU’s opreating
mode (see Table 7 in 4 Operating Modes and System Initialization). After reset, MODA
functions as LIR, an open-drain output that indicates the start of an instruction cycle. MODB
functions as V
, providing a backup battery to maintain the contents of RAM when VDD falls.
STBY
R/W
In expanded and test modes, R/W indicates the direction of transfers on the external data bus.
VRH and V
RL
These pins provide the reference voltage for the analog-to-digital converter. Use bypass
capacitors to minimize noise on these signals. Any noise on VRH and VRL will directly affect A/D
accuracy. These pins are not present on the MC68HC11FC0.
MOTOROLAMC68HC11F1/FC0
12MC68HC11FTS/D
Port Signals
On the MC68HC11F1, 54 pins are arranged into six 8-bit ports (ports A, B, C, E, F, and G) and
one 6-bit port (port D). On the MC68HC11FC0, either 52 or 49 pins are available, depending on
the package. General-purpose I/O port signals are discussed briefly in the following pragraphs.
For additional information, refer to 7 Parallel Input/Output.
Port A Pins
Port A is an 8-bit general-purpose I/O port (PA[7:0]) with a data register (PORTA) and a data
direction register (DDRA). Port A pins share functions with the 16-bit timer system. Out of reset,
PA[7:0] are general-purpose high-impedance inputs.
Port B Pins
Port B is an 8-bit output-only port. In single-chip modes, port B pins are general-purpose output
pins (PB[7:0]). In expanded modes, port B pins act as the high-order address lines ADDR[15:8].
Port C Pins
Port C is an 8-bit general-purpose I/O port with a data register (PORTC) and a data direction
register (DDRC). In single-chip modes, port C pins are general-purpose I/O pins PC[7:0]. In
expanded modes, port C pins are configured as data bus pins DATA[7:0].
Port D Pins
Port D is a 6-bit general-purpose I/O port with a data register (PORTD) and a data direction
register (DDRD). The six port D lines PD[5:0] can be used for general-purpose I/O or for the serial
communications interface (SCI) or serial peripheral interface (SPI) subsystems.
Port E Pins
Port E is an 8-bit input-only port that is also used as the analog input port for the analog-to-digital
converter. Port E pins that are not used for the A/D system can be used as general-purpose
inputs. However, PORTE should not be read during the sample portion of an A/D conversion
sequence.
NOTE
The A/D system is not available on the MC68HC11FC0. PE7 and PE0 are not
available on the 80-pin MC68HC11FC0. PE7, PE4, and PE0 are not available on
the 64-pin MC68HC11FC0.
Port F Pins
Port F is an 8-bit output-only port. In single-chip mode, port F pins are general-purpose output
pins PF[7:0]. In expanded mode, port F pins act as the low-order address outputs ADDR[7:0].
Port G Pins
Port G is an 8-bit general-purpose I/O port. When enabled, four chip select signals are alternate
functions of PG[7:4].
NOTE
PG[1:0] are not available on the 64-pin MC68HC11FC0.
MC68HC11F1/FC0 MOTOROLA
MC68HC11FTS/D13
3 Control Registers
The MC68HC11F1 and MC68HC11FC0 control registers determine most of the system’s operating
characteristics. They occupy a 96-byte relocatable memory block. Their names and bit mnemonics are
summarized in the following table. Addresses shown are the default locations out of reset.
3.1 MC68HC11F1 Control Registers
Table 5 MC68HC11F1 Register and Control Bit Assignments
The 16-bit address bus can access 64 Kbytes of memory. Because the MC68HC11F1 and
MC68HC11FC0 are intended to operate principally in expanded mode, there is no internal ROM and
the address bus is non-multiplexed. Both devices include 1 Kbyte of static RAM, a 96-byte control register block, and 256 bytes of bootstrap ROM. The MC68HC11F1 also includes 512 bytes of EEPROM.
RAM and registers can be remapped on both the MC68HC11F1 and the MC68HC11FC0. On both the
MC68HC11F1 and the MC68HC11FC0, out of reset RAM resides at $0000 to $03FF and registers reside at $1000 to $105F. On the MC68HC11F1, RAM and registers can both be remapped to any 4Kbyte boundary. On the MC68HC11FC0, RAM can be remapped to any 1-Kbyte boundary, and registers can be remapped to any 4-Kbyte boundary in the first 16 Kbytes of address space.
RAM and control register locations are defined by the INIT register, which can be written only once within the first 64 E-clock cycles after a reset in normal modes. It becomes a read-only register thereafter.
If RAM and the control register block are mapped to the same boundary, the register block has priority
of the first 96 bytes.
x
In expanded and special test modes in the MC68HC11F1, EEPROM is located from $
where x represents the value of the four high-order bits of the CONFIG register. EEPROM is enabled
by the EEON bit of the CONFIG register. In single-chip and bootstrap modes, the EEPROM is located
from $FE00 to $FFFF.
4.1 Operating Modes
Bootstrap ROM resides at addresses $BF00–$BFFF, and is only available when the MCU operates in
special bootstrap operating mode. Operating modes are determined by the logic levels applied to the
MODB and MODA pins at reset.
E00 to $xFFF,
In single-chip mode, the MCU functions as a self-contained microcontroller and has no external address
or data bus. Ports B, C and F are available for general-purpose I/O (GPIO). Ports B and F are outputs
only; each of the port C pins can be configured as input or output.
CAUTION
The MC68HC11FC0 must not be configured to boot in single-chip mode because
it has no internal ROM or EEPROM. Operation of the device in single-chip mode
will result in erratic behavior.
In expanded mode, the MCU can access external memory. Ports B and F provide the address bus, and
port C is the data bus.
Special bootstrap mode is a variation of single chip mode that provides access to the internal bootstrap
ROM. In this mode, the user can download a program into on-chip RAM through the serial communication interface (SCI).
Special test mode, a variation of expanded mode, is primarily used during Motorola’s internal production
testing, but can support emulation and debugging during program development.
Table 7 shows a summary of operating modes, mode select pins, and control bits in the HPRIO register.
1. RAM can be remapped to any 4-Kbyte boundary ($x000). “x” represents the value contained in RAM[3:0] in the
INIT register.
2. The register block can be remapped to any 4-Kbyte boundary ($y000). “y” represents the value contained in
REG[3:0] in the INIT register.
3. Special test mode vectors are externally addressed.
4. In special test mode the address locations $zD00—$zDFF are not externally addressable. “z” represents the value of bits EE[3:0] in the CONFIG register.
5. EEPROM can be remapped to any 4-Kbyte boundary ($z000). “z” represents the value contained in EE[3:0] in
the CONFIG register.
Figure 7 MC68HC11F1 Memory Map
MC68HC11F1/FC0 MOTOROLA
MC68HC11FTS/D19
$0000 —
$03FF —
—
—
—
—
—
1024 BYTES RAM
—
1
$1000 —
$105F —
$BF00 —
$BFFF —
$FE00 —
$FFC0 —
$FFFF —
SINGLE
CHIP
—
—
—
—
—
—
EXTERNAL
EXTERNAL
EXPANDED
—
—
—
—
—
—
BOOTSTRAP
SPECIAL
—
—
—
—
—
—
EXTERNAL
EXTERNAL
SPECIAL
TEST
256 BYTES
BOOTSTRAP
ROM
96-BYTE REGISTER FILE
$BFC0
SPECIAL
MODE
INTERRUPT
VECTORS
$BFFF
$FFC0
NORMAL
MODE
INTERRUPT
VECTORS
$FFFF
2
MODA = 0
MODB = 1
MODA = 1
MODB = 1
MODA = 0
MODB = 0
MODA = 1
MODB = 0
NOTES:
1. RAM can be remapped to any 1-Kbyte boundary, depending on the value contained in the RAM field in the INIT
register.
2. The register block can be remapped to $0000, $2000, or $3000, depending on the value contained in REG[1:0]
in the INIT register.
Figure 8 MC68HC11FC0 Memory Map
4.3 System Initialization Registers
HPRIO — Highest Priority Interrupt and Miscellaneous$x03C
Bit 7654321Bit 0
RBOOTSMODMDAIRVPSEL3PSEL2PSEL1PSEL0
RESET:0 0 000101Single-Chip
00100101Expanded
11010101Bootstrap
01110101Special Test
MOTOROLAMC68HC11F1/FC0
20MC68HC11FTS/D
RBOOT — Read Bootstrap ROM
RBOOT is valid only when SMOD is set to one (special bootstrap or special test mode). RBOOT can
only be written in special modes but can be read anytime.
0 = Boot loader ROM disabled and not in memory map
1 = Boot loader ROM enabled and in memory map at $BF00–$BFFF
SMOD and MDA — Special Mode Select and Mode Select A
The initial value of SMOD is the
of reset. The initial value of MDA
inverse
equals
of the logic level present on the MODB pin at the rising edge
the logic level present on the MODA pin at the rising edge of
reset. These two bits can be read at any time. They can be written at any time in special modes. Neither
bit can be written in normal modes. SMOD cannot be set once it has been cleared. Refer to Table 8.
This bit can be read at any time. It can be written at any time in special modes, but only once in normal
modes. In single-chip and bootstrap modes, IRV has no meaning or effect.
0 = Internal reads not visible
1 = Data from internal reads is driven on the external data bus
PSEL[3:0] — See 5.2 Reset and Interrupt Registers, page 27.
INIT — RAM and I/O Mapping (MC68HC11FC0 only)$x03D
Bit 7654321Bit 0
RAM5RAM4RAM3RAM2RAM1RAM0REG1REG0
RESET:00000001
The INIT register can be written only once in first 64 cycles out of reset in normal modes, or at any time
in special modes.
NOTE
The register diagram above applies to the MC68HC11FC0 only. A diagram and bit
descriptions of the INIT register in the MC68HC11F1 are provided elsewhere in
this section.
RAM[5:0] — Internal RAM Map Position
These bits determine the upper six bits of the RAM address and allow mapping of the RAM to any oneKbyte boundary.
REG[1:0] — Register Block Map Position
These bits determine the location of the register block, as shown in Table 9.