Version: 1.18
PRELIMINARY/CONFIDENTIAL
TrueSpeech® Co-Processor
9.25.3
Write GPIO Pins
Command = 0BXXH:
0000 1011
GPIO-7
(7)
GPIO-6
(6)
X
X
GPIO-3
(3)
GPIO-2
(2)
GPIO-1
(1)
X
(15-8)
(5)
(4)
(0)
Status = 00XXH:
0000 0000
GPIO-7
(7)
GPIO-6
(6)
FRN
(5)
X
GPIO-3
(3)
GPIO-2
(2)
GPIO-1
(1)
DATA
FLAG
(0)
(15-8)
(4)
The status response echoes the GPIO bit values in the 0BXXH commands. Regardless of the GPIO direction
configured, the status echoes the value written in the 0BXXH command. If the pin is an input, it is not affected by
this operation. Bits 0, 4 and 5 of the status response show the current state of the CT8022 reserved output bits.
9.25.4
Read GPIO Pins
Command = 5143H (this is the Read FR - frame interrupt command):
0101
0001
0100
(7-4)
0011
(3-0)
(15-12)
(11-8)
Status = YYXXH:
GPIO-7
(read)
GPIO-6
(read)
GPIO-5
(read)
GPIO-4 FRN
GPIO-3
(read)
GPIO-2
(read)
GPIO-1
(read)
GPIO-0
DATA-FLAG
(read)
(read)
(15)
(14)
(13)
(12)
(11)
(10)
(9)
(8)
GPIO-7
(readback)
GPIO-6
(readback)
GPIO-5
(readback)
GPIO-4 FRN
(readback)
GPIO-3
(readback)
GPIO-2
(readback)
GPIO-1
(readback)
GPIO-0
DATA-FLAG
(readback)
(7)
(6)
(5)
(4)
(3)
(2)
(1)
(0)
The most significant 8 bits “YY” of the status response show the state of the GPIO input pins.
The least significant 8 bits “XX” of the status response show the last data written to the GPIO pins (readback).
If the GPIO pin is configured as an input, the state of the input pin is reflected in the matching bit in the YY upper
byte of the status reply. The matching bit in the XX lower byte shows the last value written to the pin. This
readback value will control the state of the pin if the direction bit is changed to program the pin as an output. This
represents the potential state of the pin, if it is changed to an output.
If the GPIO pin is configured as an output, the state of the pin as sensed by the GPIO hardware will be reflected in
the YY upper byte (reading the state of the actual output pin). The last value actually written to the pin will be
shown in the XX lower byte. Under normal circumstances, the bit value in XX and YY will match. Only under
abnormal circumstances, for example a short circuit to ground, will the XX and YY bit states be different.
This is also the command shown in Section 9.16 of this data sheet, used for reading the state of the Frame Interrupt
pin (FRN).
CT8022A11AQC FW Revision 0118 DSP GROUP, INC., 3120 SCOTT BOULEVARD
SANTA CLARA, CA 95054 PH: 408 986 – 4300 FAX: 408 986 – 4490
159
All specifications are subject to change without prior notice.
ETC [ ETC ]
