Bio Pin Multiplexing; Software View; Figure 10-4.Logic Flow Diagram For Bio Configuration; Table 10-1. Bio Pin Multiplexing - Lucent Technologies DSP1617 Information Manual

DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
Bit I/O Unit
10.1 BIO Hardware Function

10.1.4 BIO Pin Multiplexing

The pins for the BIO are shared with functions of the PIO and the VEC[3:0] functions.
sponding signal names. The bold font indicates the functions that are the default after RESET. The BIO functions
IOBIT[7:4] are selected if bit 12 (EBIOH) of the ioc register is set. The BIO functions IOBIT[3:0] are selected if bit
10 (ESIO2) of the ioc register is set.
Note: After reset, VEC[3:0] are the outputs and are driven low; and if IOBIT[7:4] are to be used as inputs, EBIOH
must be set before the inputs are driven high.

Table 10-1. BIO Pin Multiplexing

Symbol
IOBIT0/PB4 IOBIT4/VEC3
IOBIT1/PB5 IOBIT5/VEC2
IOBIT2/PB6 IOBIT6/VEC1
IOBIT3/PB7 IOBIT7/VEC0

10.2 Software View

The cbit and sbit registers, the flags, and the pertinent instructions make up the software view.
flow diagram showing the decisions made for each bit to determine the configuration of the BIO. Each decision is
determined by a bit in the designated fields of the sbit or cbit registers. In all cases, the data on the device pins is
stored in the VALUE field of sbit.
YES, 0
MASKED
?
IGNORE
INPUT
10-4
(continued)
Symbol
INPUT
INPUT, 0
OUTPUT?
cbit HIGH BYTE
NO, 1
cbit LOW BYTE
NO YES
PATTERN
MATCH ?
FLAG SETTING
LOGIC
Figure 10-4. Logic Flow Diagram for BIO Configuration
sbit HIGH BYTE
OUTPUT, 1
OR
TOGGLE,1
cbit LOW BYTE
1
DATA = ?
NO CHANGE
TOGGLE
ON OUTPUT
OUTPUT
DRAFT COPY
Information Manual
Table 10-1 shows the corre-
Figure 10-4
ENABLE
OUTPUT
BUFFER
cbit HIGH BYTE
DATA,0
MODE?
cbit LOW BYTE
0 1
DATA = ?
1 TO
0 TO
OUTPUT
OUTPUT
Lucent Technologies Inc.
April 1998
is a
0
5-4204