C8051F80x-83x
SFR Definition 23.5. P1MASK: Port 1 Mask Register
Bit
Name
Type
Reset
0
0
0
0
7
6
5
4
3
2
1
0
P1MASK[7:0]
R/W
0
0
0
0
SFR Address = 0xEE
Bit
Name
7:0
P1MASK[7:0]
Port 1 Mask Value.
Function
Selects P1 pins to be compared to the corresponding bits in P1MAT.
0: P1.n pin logic value is ignored and cannot cause a Port Mismatch event.
1: P1.n pin logic value is compared to P1MAT.n.
Note:
P1.4–P1.7 are not available on 16-pin packages.
SFR Definition 23.6. P1MAT: Port 1 Match Register
Bit
Name
Type
Reset
1
1
1
1
7
6
5
4
3
2
1
0
P1MAT[7:0]
R/W
1
1
1
1
SFR Address = 0xED
Bit
Name
7:0
P1MAT[7:0]
Port 1 Match Value.
Function
Match comparison value used on Port 1 for bits in P1MASK which are set to 1.
0: P1.n pin logic value is compared with logic LOW.
1: P1.n pin logic value is compared with logic HIGH.
Note:
P1.4–P1.7 are not available on 16-pin packages.
23.6. Special Function Registers for Accessing and Configuring Port I/O
All Port I/O are accessed through corresponding special function registers (SFRs) that are both byte
addressable and bit addressable. When writing to a Port, the value written to the SFR is latched to main-
tain the output data value at each pin. When reading, the logic levels of the Port's input pins are returned
regardless of the XBRn settings (i.e., even when the pin is assigned to another signal by the Crossbar, the
Port register can always read its corresponding Port I/O pin). The exception to this is the execution of the
read-modify-write instructions that target a Port Latch register as the destination. The read-modify-write
instructions when operating on a Port SFR are the following: ANL, ORL, XRL, JBC, CPL, INC, DEC, DJNZ
and MOV, CLR or SETB, when the destination is an individual bit in a Port SFR. For these instructions, the
value of the latch register (not the pin) is read, modified, and written back to the SFR.
152
Rev. 1.0
SILABS [ SILICON LABORATORIES ]
