Microchip Technology DV164136 Data Sheet
PIC18F87J11 FAMILY
DS39778E-page 80
2007-2012 Microchip Technology Inc.
6.3.4.1
Shared Address SFRs
In several locations in the SFR bank, a single address
is used to access two different hardware registers. In
these cases, a “legacy” register of the standard PIC18
SFR set (such as OSCCON, T1CON, etc.) shares its
address with an alternate register. These alternate reg-
isters are associated with enhanced configuration
options for peripherals or with new device features not
included in the standard PIC18 SFR map. A complete
list of shared register addresses and the registers
associated with them is provided in
is used to access two different hardware registers. In
these cases, a “legacy” register of the standard PIC18
SFR set (such as OSCCON, T1CON, etc.) shares its
address with an alternate register. These alternate reg-
isters are associated with enhanced configuration
options for peripherals or with new device features not
included in the standard PIC18 SFR map. A complete
list of shared register addresses and the registers
associated with them is provided in
.
Access to the alternate registers is enabled in software
by setting the ADSHR bit in the WDTCON register
(
by setting the ADSHR bit in the WDTCON register
(
). ADSHR must be manually set or
cleared to access the alternate or legacy registers, as
required. Since the bit remains in a given state until
changed, users should always verify the state of
ADSHR before writing to any of the shared SFR
addresses.
required. Since the bit remains in a given state until
changed, users should always verify the state of
ADSHR before writing to any of the shared SFR
addresses.
6.3.4.2
Context Defined SFRs
In addition to the shared address SFRs, there are
several registers that share the same address in the
SFR space, but are not accessed with the ADSHR bit.
Instead, the register’s definition and use depends on
the operating mode of its associated peripheral. These
registers are:
• SSPxADD and SSPxMSK: These are two
several registers that share the same address in the
SFR space, but are not accessed with the ADSHR bit.
Instead, the register’s definition and use depends on
the operating mode of its associated peripheral. These
registers are:
• SSPxADD and SSPxMSK: These are two
separate hardware registers, accessed through a
single SFR address. The operating mode of the
MSSPx module determines which register is
being accessed. See
single SFR address. The operating mode of the
MSSPx module determines which register is
being accessed. See
for additional details.
• PMADDRH/L and PMDOUT2H/L: In this case,
these named buffer pairs are actually the same
physical registers. The PMP module’s operating
mode determines what function the registers take
on. See
physical registers. The PMP module’s operating
mode determines what function the registers take
on. See
for
additional details.
TABLE 6-4:
SHARED SFR ADDRESSES FOR PIC18F87J11 FAMILY DEVICES
Address
Name
Address
Name
Address
Name
FD3h
(D)
OSCCON
FCDh
(D)
T1CON
FC2h
(D)
ADCON0
(A)
REFOCON
(A)
ODCON3
(A)
ANCON1
FCFh
(D)
TMR1H
FCCh
(D)
TMR2
FC1h
(D)
ADCON1
(A)
ODCON1
(A)
PADCFG1
(A)
ANCON0
FCEh
(D)
TMR1L
FCBh
(D)
PR2
F77h
(D)
PR4
(A)
ODCON2
(A)
MEMCON
(A)
CVRCON
Legend:
(D) = Default SFR, accessible only when ADSHR = 0; (A) = Alternate SFR, accessible only when ADSHR = 1.
Note 1:
This bit is implemented in 80-pin devices only.