Program Memory; Special-Purpose Memory - Intel 8XC196K Series User Manual

Table of Contents

Program Memory

Program memory occupies a memory partition beginning at 2080H. (See Table 4-1 for the ending

address for each device.) This entire partition is available for storing executable code and data.

The EA# signal controls access to program memory. Accesses to this address range are directed

to internal memory if EA# is held high and to external memory if EA# is held low. For devices

without internal nonvolatile memory, the EA# signal must be tied low. EA# is latched at reset.

We recommend that you write FFH (the opcode for the RST instruction) to

unused program memory locations. This causes a device reset if a program

unintentionally begins to execute in unused memory.

Special-purpose memory resides in locations 2000–207FH (Table 4-2). It contains several re-

served memory locations, the chip configuration bytes (CCBs), and vectors for both peripheral

transaction server (PTS) and standard interrupts. Accesses to this address range are directed to

internal memory if EA# is held high and to external memory if EA# is held low. For devices with-

out internal nonvolatile memory, the EA# signal must be tied low. EA# is latched at reset.

Table 4-2. Special-purpose Memory Addresses

Reserved (each byte must contain FFH)

Upper interrupt vectors

Security key

Reserved (must contain 20H)

Reserved (must contain FFH)

Reserved (must contain 20H)

Reserved (must contain FFH)

Reserved (must contain 20H)

Reserved (must contain 20H)

OFD flag (see page 13-12 and page 16-8)

Reserved (each byte must contain FFH)

Lower interrupt vectors

MEMORY PARTITIONS