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’C209 Memory and I/O Spaces
11-8
(4K) are mapped to external data memory. Thus, a total of 8K additional
addresses (4K program and 4K data) are available for external memory.
DARAM blocks B1 and B2 are fixed, but DARAM block B0 may be mapped to
program space or data space, depending on the value of the CNF bit (bit 12
of status register ST1):
When CNF = 0, B0 is mapped to data space and is accessible at data ad-
dresses 0200h–02FFh. Note that the addressable external
program
memory increases by 512 words. At reset, CNF = 0.
When CNF = 1, B0 is mapped to program space and is accessible at pro-
gram addresses FF00h–FFFFh.
Table 11–1 lists the available program memory configurations for the ’C209;
Table 11–2 lists the data-memory configurations. Note these facts:
Program-memory addresses 0000h–003Fh are used for the interrupt vec-
tors.
Data-memory addresses 0000h–005Fh contain on-chip memory-mapped
registers and reserved memory.
Two other on-chip data-memory ranges are always reserved:
0080h–01FFh and 0400h–07FFh.
Table 11–1. ’C209 Program-Memory Configuration Options
MP/MC RAMEN CNF
ROM
(hex)
SARAM
(hex)
DARAM B0
(hex)
External
(hex)
Reserved
(hex)
0 0 0 0000–0FFF – – 1000–FFFF –
0 0 1 0000–0FFF – FF00–FFFF 1000–FDFF FE00–FEFF
0 1 0 0000–0FFF 1000–1FFF – 2000–FFFF –
0 1 1 0000–0FFF 1000–1FFF FF00–FFFF 2000–FDFF FE00–FEFF
1 0 0 – – – 0000–FFFF –
1 0 1 – – FF00–FFFF 0000–FDFF FE00–FEFF
1 1 0 – 1000–1FFF – 0000–0FFF
2000–FFFF
–
1
1 1 – 1000–1FFF FF00–FFFF 0000–0FFF
2000–FDFF
FE00–FEFF