Datascope Passport 2, Руководство по обслуживанию

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Front End Module Theory of Operation
2 - 14 0070-10-0441 Passport 2®/Passport 2 LT™ Service Manual
Emulation capabilities and high level debugging are included using a JTAG port configured
as a Background Debug Mode (BDM) connector. A 26-pin header connector, J204, is
provided.
Hardware multiply and accumulate (MAC) functionality for implementing the digital software
filters is provided.
No external hardware interrupts are required.
2.2.6 Memory
Since the processor operates in the single chip mode, only internal memory is used. The
device contains a ColdFire Flash Module (CFM), which is constructed with eight banks of
32K x 16-bit Flash to generate a 512-Kbyte, 32-bit wide electrically erasable and
programmable read-only memory array. The CFM is ideal for program and data storage for
single-chip applications and allows for field reprogramming without external high-voltage
sources. The voltage required to program and erase the Flash is generated internally by on-
chip charge pumps. Program and erase operations are performed under CPU control
through a command driven interface to an internal state machine. All Flash physical blocks
can be programmed or erased at the same time, however, it is not possible to read from a
Flash physical block while the same block is being programmed or erased. The array used in
the MCF5282 makes it possible to program or erase one pair of Flash physical blocks under
the control of software routines executing out of another pair.
Some of the requirements satisfied by the design are 8KB SRAM and 96KB Flash EEPROM.
The SRAM is used for the BOOT RAM, stack, and vector table. The Flash is used for the run-
time code and satisfies the minimum of 64K, but expandable to at least 96K for ST/
Arrhythmia and future growth. The 96K is divided into 2 blocks: 8K minimum for the
bootloader code, and 88K minimum for the application code.
The Flash has a bulk erase mode. It is intended that the bootloader can be erased and
changed only at the factory, while the application code can be reloaded in the field. The
Flash has a security register, a protection register, and a lock control bit, all used to protect
the boot code from accidental erasure. For added protection, a separate external program/
erase jumper J7 is supplied, giving the capability to use jumpers for factory programming.
The jumper is connected to a general purpose I/O pin and is only read by software in order
to have permission to program the boot code. The application code is that which actually
runs the module, following initialization, and is field downloadable via the module bus. The
bootloader code performs basic initialization of the system, then passes control to the
application. The bootloader also contains support for module bus downloads of the
application code, in the event the application code is corrupted or is to be updated. The
system can always recover from a failed download, since the bootloader cannot be
accidentally erased or corrupted outside the factory.