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Chapter 19 Port Integration Module (S12XFPIMV2)
MC9S12XF - Family Reference Manual, Rev.1.19
Freescale Semiconductor
849
19.3.4
Port B Data Register (PORTB)
1. Read: Anytime. In emulation modes, read operations will return the data from the external bus, in all other modes the data source
is depending on the data direction value.
Write: Anytime. In emulation modes, write operations will also be directed to the external bus.
Table 19-4. PORTA Register Field Descriptions
Field
Description
7-0
PA
Port A general purpose input/output data—Data Register
Port A pins 7 through 0 are associated with address outputs ADDR[15:8] respectively in expanded modes. In
emulation modes the address is multiplexed with IVD[15:8].
When not used with the alternative function, these pins can be used as general purpose I/O.
If the associated data direction bits of these pins are set to 1, a read returns the value of the port register, otherwise
the buffered pin input state is read.
Address 0x0001 (PRR)
Access: User read/write(1)
1. Read: Anytime. In emulation modes, read operations will return the data from the external bus, in all other modes the data source
is depending on the data direction value.
Write: Anytime. In emulation modes, write operations will also be directed to the external bus.
76543210
R
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PB0
W
Altern.
Function
ADDR7
mux
IVD7
ADDR6
mux
IVD6
ADDR5
mux
IVD5
ADDR4
mux
IVD4
ADDR3
mux
IVD3
ADDR2
mux
IVD2
ADDR1
mux
IVD1
ADDR0
mux
IVD0
or
UDS
Reset
00000000
Figure 19-2. Port B Data Register (PORTB)
Table 19-5. PORTB Register Field Descriptions
Field
Description
7-0
PB
Port B general purpose input/output data—Data Register
Port B pins 7 through 0 are associated with address outputs ADDR[7:0] respectively in expanded modes. In
emulation modes the address is multiplexed with IVD[7:0]. In normal expanded mode pin 0 is related to the UDS
input.
When not used with the alternative function, these pins can be used as general purpose I/O.
If the associated data direction bits of these pins are set to 1, a read returns the value of the port register, otherwise
the buffered pin input state is read.