
Data Sheet
June 2001
DSP16410B Digital Signal Processor
Agere Systems Inc.
Agere Systems—Proprietary
Use pursuant to Company instructions
49
4 Hardware Architecture
(continued)
4.9 Bit Input/Output Units (BIO
0—1
)
The DSP16410B has two bit I/O units, BIO0 for CORE0
and BIO1 for CORE1. Each BIO unit connects to
seven bidirectional pins, IO0BIT[6:0] for BIO0 and
IO1BIT[6:0] for BIO1. User software running in CORE0
controls and monitors BIO0 via its
sbit
and
cbit
regis-
ters. User software running in CORE1 controls and
monitors BIO1 via its
sbit
and
cbit
registers. The soft-
ware can:
I
Individually configure each pin as an input or output.
I
Read the current state of the pins.
I
Test the combined state of input pins.
I
Individually set, clear, or toggle output pins.
The DIREC[6:0] field (
sbit
[14:8]—see
Table 16
) con-
trols the direction of the corresponding IO
0,1
BIT[6:0]
pin—a logic 0 configures the pin as an input or a logic 1
configures it as an output. Reset clears the
DIREC[6:0] field, configuring all BIO pins as inputs by
default. The read-only VALUE[6:0] field (
sbit
[6:0])
contains the current state of the corresponding pin,
regardless of whether the pin is configured as an input
or output.
The
cbit
register (
Table 17 on page 50
) contains two
7-bit fields, MODE[6:0]/MASK[6:0] and
DATA[6:0]/PAT[6:0]. The meaning of the individual
bits in these fields, MODE[n]/MASK[n] and
DATA[n]/PAT[n], is based on whether the correspond-
ing IO
0,1
BIT[n] pin is configured as an input or an
output. If IO
0,1
BIT[n] is configured as an input, the
fields are MASK[n] and PAT[n]. If IO
0,1
BIT[n] is
configured as an output, the fields are MODE[n] and
DATA[n].
Table 18 on page 51
summarizes the func-
tion of the MODE[6:0]/MASK[6:0] and
DATA[6:0]/PAT[6:0] fields.
If the software configures an IO
0,1
BIT[n] pin as an
output and:
I
If the software clears MODE[n] and clears DATA[n],
the BIO
0,1
drives the pin low.
I
If the software clears MODE[n] and sets DATA[n], the
BIO
0,1
drives the pin high.
I
If the software sets MODE[n] and clears DATA[n], the
BIO does not change the state of the pin.
I
If the software sets MODE[n] and sets DATA[n], the
BIO
0,1
toggles (inverts) the state of the pin.
If an IO
0,1
BIT[n] pin is configured as an input and
the software sets MASK[n], the BIO
0,1
tests the
state of the pin by comparing it to the PAT[n] (pattern)
field. BIO
0,1
sets or clears its flags based on the
result of the comparison of all its tested inputs:
I
ALLT (all true) is set if all of the tested inputs match
the test pattern.
I
ALLF (all false) is set if all of the tested inputs do not
match the test pattern.
I
SOMET (some true) is set if some or all of the tested
inputs match the test pattern.
I
SOMEF (some false) is set if some or all of the
tested inputs do not match the test pattern.
Table 16. sbit (BIO Status/Control) Register
15
14—8
7
6—0
Reserved
DIREC[6:0]
Reserved
VALUE[6:0]
Bit
Field
Value
Description
R/W
Reset
Value
0
0
15
Reserved
DIREC[6:0]
(Controls direc-
tion of pins)
Reserved
VALUE[6:0]
(Current value of
pins)
0
0
1
Reserved—write with zero.
Configure the corresponding IO
0,1
BIT[6:0] pin as an input.
Configure the corresponding IO
0,1
BIT[6:0] pin as an output.
R/W
R/W
14—8
7
—
0
1
Reserved.
The current state of the corresponding IO
0,1
BIT[6:0] pin is logic 0.
The current state of the corresponding IO
0,1
BIT[6:0] pin is logic 1.
R
R
X
P
§
6—0
For this column, X indicates unknown on powerup reset and unaffected on subsequent reset.
This field is read-only—writing the VALUE[6:0] field of
sbit
has no effect. If the user software toggles a bit in the DIREC[6:0] field, there is a
latency of one cycle until the VALUE[6:0] field reflects the current state of the corresponding IO
0,1
BIT[6:0] pin. If an IO
0,1
BIT[6:0] pin is
configured as an output (DIREC[6:0] = 1) and the user software writes
cbit
to change the state of the pin, there is a latency of two cycles until
the VALUE[6:0] field reflects the current state of the corresponding IO
0,1
BIT[6:0] output pin.
§ The IO
0,1
BIT[6:0] pins are configured as inputs after reset. If external circuitry does not drive an IO
0,1
BIT[n] pin, the VALUE[n] field is
undefined after reset.