MC68HC711E20CFN2 Freescale Semiconductor, MC68HC711E20CFN2 Datasheet - Page 205

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MC68HC711E20CFN2

Manufacturer Part Number
MC68HC711E20CFN2
Description
IC MCU 20K 2MHZ OTP 52-PLCC
Manufacturer
Freescale Semiconductor
Series
HC11r
Datasheets

Specifications of MC68HC711E20CFN2

Core Processor
HC11
Core Size
8-Bit
Speed
2MHz
Connectivity
SCI, SPI
Peripherals
POR, WDT
Number Of I /o
38
Program Memory Size
20KB (20K x 8)
Program Memory Type
OTP
Eeprom Size
512 x 8
Ram Size
768 x 8
Voltage - Supply (vcc/vdd)
4.5 V ~ 5.5 V
Data Converters
A/D 8x8b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
52-PLCC
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Driving Boot Mode from Another M68HC11
Driving Boot Mode from Another M68HC11
A second M68HC11 system can easily act as the host to drive bootstrap loading of an M68HC11 MCU.
This method is used to examine and program non-volatile memories in target M68HC11s in Freescale
EVMs. The following hardware and software example will demonstrate this and other bootstrap mode
features.
The schematic in
Figure 6
shows the circuitry for a simple EPROM duplicator for the MC68HC711E9. The
circuitry is built in the wire-wrap area of an M68HC11EVBU evaluation board to simplify construction. The
schematic shows only the important portions of the EVBU circuitry to avoid confusion. To see the
complete EVBU schematic, refer to the M68HC11EVBU Universal Evaluation Board User’s Manual,
Freescale document order number M68HC11EVBU/D.
The default configuration of the EVBU must be changed to make the appropriate connections to the
circuitry in the wire-wrap area and to configure the master MCU for bootstrap mode. A fabricated jumper
must be installed at J6 to connect the XTAL output of the master MCU to the wire-wrap connector P5,
which has been wired to the EXTAL input of the target MCU. Cut traces that short across J8 and J9 must
be cut on the solder side of the printed circuit board to disconnect the normal SCI connections to the
RS232 level translator (U4) of the EVBU. The J8 and J9 connections can be restored easily at a later time
by installing fabricated jumpers on the component side of the board. A fabricated jumper must be installed
across J3 to configure the master MCU for bootstrap mode.
One MC68HC711E9 is first programmed by other means with a desired 12-Kbyte program in its EPROM
and a small duplicator program in its EEPROM. Alternately, the ROM program in an MC68HC11E9 can
be copied into the EPROM of a target MC68HC711E9 by programming only the duplicator program into
the EEPROM of the master MC68HC11E9. The master MCU is installed in the EVBU at socket U3. A
blank MC68HC711E9 to be programmed is placed in the socket in the wire-wrap area of the EVBU (U6).
With the V
power switch off, power is applied to the EVBU system. As power is applied to the EVBU,
PP
the master MCU (U3) comes out of reset in bootstrap mode. Target MCU (U6) is held in reset by the PB7
output of master MCU (U3). The PB7 output of U3 is forced to 0 when U3 is reset. The master MCU will
later release the reset signal to the target MCU under software control. The RxD and TxD pins of the target
MCU (U6) are high-impedance inputs while U6 is in reset so they will not affect the TxD and RxD signals
of the master MCU (U3) while U3 is coming out of reset. Since the target MCU is being held in reset with
MODA and MODB at 0, it is configured for the PROG EPROM emulation mode, and PB7 is the output
enable signal for the EPROM data I/O (input/output) pins. Pullup resistor R7 causes the port D pins,
including RxD and TxD, to remain in the high-impedance state so they do not interfere with the RxD and
TxD pins of the master MCU as it comes out of reset.
As U3 leaves reset, its mode pins select bootstrap mode so the bootloader firmware begins executing. A
break is sent out the TxD pin of U3. Pullup resistor R10 and resistor R9 cause the break character to be
seen at the RxD pin of U3. The bootloader performs a jump to the start of EEPROM in the master MCU
(U3) and starts executing the duplicator program. This sequence demonstrates how to use bootstrap
mode to pass control to the start of EEPROM after reset.
The complete listing for the duplicator program in the EEPROM of the master MCU is provided in
Listing 1. MCU-to-MCU Duplicator
Program.
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor
205

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