LM3S600-IQN20-A0T Bookham Technology, Inc., LM3S600-IQN20-A0T Datasheet - Page 126

• Manufacturer Part Number: LM3S600-IQN20-A0T
• Description: Microcontroller
• Manufacturer: Bookham Technology, Inc.

General-Purpose Input/Outputs (GPIOs)
GPIO Data (GPIODATA)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
Offset 0x000
Type R/W, reset 0x0000.0000
126
Reset
Reset
Type
Type
Bit/Field
31:8
7:0
RO
RO
31
15
0
0
Register 1: GPIO Data (GPIODATA), offset 0x000
The GPIODATA register is the data register. In software control mode, values written in the
GPIODATA register are transferred onto the GPIO port pins if the respective pins have been
configured as outputs through the GPIO Direction (GPIODIR) register (see page 127).
In order to write to GPIODATA, the corresponding bits in the mask, resulting from the address bus
bits [9:2], must be High. Otherwise, the bit values remain unchanged by the write.
Similarly, the values read from this register are determined for each bit by the mask bit derived from
the address used to access the data register, bits [9:2]. Bits that are 1 in the address mask cause
the corresponding bits in GPIODATA to be read, and bits that are 0 in the address mask cause the
corresponding bits in GPIODATA to be read as 0, regardless of their value.
A read from GPIODATA returns the last bit value written if the respective pins are configured as
outputs, or it returns the value on the corresponding input pin when these are configured as inputs.
All bits are cleared by a reset.
RO
RO
30
14
0
0
reserved
Name
DATA
RO
RO
29
13
0
0
RO
RO
28
12
0
0
reserved
RO
RO
Type
27
11
R/W
0
0
RO
RO
RO
26
10
0
0
Reset
0x00
0x00
RO
RO
25
0
9
0
Preliminary
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
GPIO Data
This register is virtually mapped to 256 locations in the address space.
To facilitate the reading and writing of data to these registers by
independent drivers, the data read from and the data written to the
registers are masked by the eight address lines ipaddr[9:2]. Reads
from this register return its current state. Writes to this register only affect
bits that are not masked by ipaddr[9:2] and are configured as
outputs. See “Data Register Operation” on page 120 for examples of
reads and writes.
RO
RO
24
0
8
0
reserved
R/W
RO
23
0
7
0
R/W
RO
22
0
6
0
R/W
RO
21
0
5
0
R/W
RO
20
0
4
0
DATA
R/W
RO
19
0
3
0
R/W
RO
18
0
2
0
October 01, 2007
R/W
RO
17
0
1
0
R/W
RO
16
0
0
0