Datasheet

HPC16003 Operating Modes

EXPANDED ROMLESS MODE (HPC16003)

Because the HPC16003 has no on-chip ROM, it has only

one mode of operation, the Expanded ROMless Mode. The

EXM pin must be pulled high (logic ‘‘1’’) on power up, the

EA bit in the PSW register should be set to a ‘‘1’’. The

HPC16003 is a ROMless device and is intended for use with

external memory. The external memory may be any combi-

nation of ROM and RAM. Up to 64k bytes of external mem-

ory may be accessed. It is necessary to vector on reset to

an address between F000 and FFFF, therefore the user

should have external memory at these addresses. The EA

bit in the PSW register must immediately be set to ‘‘1’’ at the

beginning of the user’s program to disable illegal address

detection in the WATCHDOG logic.

TABLE II. HPC16003 Operating Modes

Operating EXM EA Memory

Mode Pin Bit Configuration

Expanded ROMless 1 1 0200:FFFF off-chip

Note: The on-chip RAM and Registers (0000:01FF) of the HPC16003 may

be accessed at all times.

TL/DD/8801–17

FIGURE 15. Single-Chip Mode

TL/DD/8801–18

FIGURE 16. 8-Bit External Memory