Chapter 2 Port Integration Module (S12XEP100PIMV1)
MC9S12XE-Family Reference Manual , Rev. 1.19
Freescale Semiconductor
113
2.3.11
Port E Data Register (PORTE)
Address 0x0008 (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.
7
6
5
4
3
2
1
0
R
PE7
PE6
PE5
PE4
PE3
PE2
PE1
PE0
W
Altern.
Function
XCLKS
or
ECLKX2
MODB
or
TAGHI
MODA
or
RE
or
TAGLO
ECLK
EROMCTL
or
LSTRB
or
LDS
RW
or
WE
IRQ
XIRQ
Reset
0
0
0
0
0
0
—
(2)
2. These registers are reset to zero. Two bus clock cycles after reset release the register values are updated with the associated
pin values.
= Unimplemented or Reserved
Figure 2-9. Port E Data Register (PORTE)
Table 2-12. PORTE Register Field Descriptions
Field
Description
7-2
PE
Port E general purpose input/output data
—Data Register
Port E bits 7 through 0 are associated with external bus control signals and interrupt inputs. These include mode
select (MODB, MODA), E clock, double frequency E clock, Instruction Tagging High and Low (TAGHI, TAGLO),
Read/Write (RW), Read Enable and Write Enable (RE, WE), Lower Data Select (LDS).
When not used with the alternative functions, Port E pins 7-2 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.
Pins 6 and 5 are inputs with enabled pull-down devices while RESET pin is low.
Pins 7 and 3 are inputs with enabled pull-up devices while RESET pin is low.
1
PE
Port E general purpose input data and interrupt
—Data Register, IRQ input.
This pin can be used as general purpose and IRQ input.
0
PE
Port E general purpose input data and interrupt
—Data Register, XIRQ input.
This pin can be used as general purpose and XIRQ input.
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:
S12XE
products
in
208
MAPBGA
packages