ST10R272L - SYNCHRONOUS SERIAL PORT
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is used to specify the SSP address area. Contrary to the BUSCONx/ADDRSELx registers,
the XBCON1/XADRS1 registers are mask-programmed, i.e. they are not software
programmable.
The mask-programming of these registers is:
The XBCON1 register is organized like the BUSCONx registers except that there is no
option for read/write chip selects (bits 14 and 15). With the mask-programmed value shown
above, the following options are selected:
Note
The XBUSACT bit of register XBCON1 only enables accesses to the SSP, it does
not control the external bus (as the other BUSACT bits in the BUSCONs).
The XADRS0 register is organized like the other ADDRSELx registers except that it uses the
reduced address ranges, which are defined for XBUS Peripherals. With the
mask-programmed value shown above, the following options are selected:
Fixing the SSP address area to address EF00h in segment 0, has the advantage that the
SSP is accessible from data-page 3, the ‘system’ data page. This data-page is usually
accessed through the ‘system’ data-page pointer DPP3. In this way, the internal addresses,
such as SFRs, internal RAM, and the SSP registers, are all located into the same data-page,
and form a contiguous address space.
XBCON1: 04BFh
XADRS1: 0EF0h
XRDYEN:
0
READY disabled
XBUSACT:
1
XBUS active
XALECTL:
0
No ALE Lengthening
XBTYP:
10
16-bit DEMUX Bus
XMTTC:
1
No Tri-State Waitstate
XRWDC:
1
No Read/Write Delay
XMTRC:
1101
0 Waitstate
ADDR:
00’EF00h
SSP address area starts at EF00h in segment 0
GSZ:
0000
SSP address area covers 256 bytes