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4-1
Memory and I/O Spaces
Memory and I/O Spaces
This chapter describes the ’C2xx memory configuration options and the ad-
dress maps of the individual ’C2xx devices. It also illustrates typical ways of
interfacing the ’C2xx with external memory and external input/output (I/O)
devices.
Each ’C2xx device has a 16-bit address line that accesses four individually se-
lectable spaces (224K words total):
A 64K-word program space
A 64K-word local data space
A 32K-word global data space
A 64K-word I/O space
Also available on select ’C2xx devices are an on-chip boot loader and a HOLD
operation. The on-chip boot loader allows a ’C2xx to boot software from an
8-bit external ROM to a 16-bit external RAM at reset. The HOLD operation al-
lows a ’C2xx to give external devices direct memory access to external pro-
gram, data, and I/O spaces.
Topic Page
4.1 Overview of the Memory and I/O Spaces 4-2. . . . . . . . . . . . . . . . . . . . . . . .
4.2 Program Memory 4-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3 Local Data Memory 4-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4 Global Data Memory 4-11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5 Boot Loader 4-14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6 I/O Space 4-23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7 Direct Memory Access Using the HOLD Operation 4-27. . . . . . . . . . . . . .
4.8 Device-Specific Information 4-31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 4