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14.5 Headers
LZT 123 7589 R1A
14. USING THE DEVELOPER'S KIT
Header
Connections
PCM
ULD, DLD,
OUT, IN, SYN,
CLK
SIM
VCC, RST,
CLK, VPP,
DAT, PR#,
GND
KEYPAD
C0, C1, C2,
C3, C4, R1,
R2, R3, R4
P0, P1, P2, P3,
2
I
C GPIO
P4, P5, P6, P7,
INT
ATMS
ATMS
GND
GND
Description
Carries digital audio PCM signals for access by
user application.
Note: In order for analog audio to be created
internally by the radio device, signal ULD must
be connected to OUT for the MIC path and
signal DLD must be connected to IN for the EAR
path.
This connector allows access to the SIM
interface signals. These test points are
connected in parallel with SIM connector 'X5'.
Note: If this header is used to attach to an
external SIM, an internal SIM fitted into
connector 'X5' must be removed.
This header provides all the connections
required to connect to a standard 20 key (5
columns x 4 rows) keypad matrix. 'C#' are output
drivers to connect to keypad columns. 'R#' are
input receivers to connect to keypad rows.
Note: C0 is a virtual keypad column driver and is
simply a connection to ground. C0 therefore
does not appear on the radio device as a
keypad driver output. The keypad interface
recognises when the rows (R1-R4) are
connected logic 'low'. If this is registered while
the columns (C1-C4) are idle then it is accepted
that the 'active' column is C0 (column zero).
This header provides a general purpose I/O port
2
from the I
C to GPIO interface. P0-P7 are the 8
bits of the data port. INT is the interrupt output of
the interface. The interface IC which drives
these signals is part number PCF8574AT from
Philips Semiconductor.
In addition to being able to feed in a
microphone signal from an alternative source,
this pin can be used to answer an incoming
telephone call. By momentarily connecting this
signal to GND when an incoming call is 'ringing',
the radio device will 'answer' the call.
These two headers can be used as the signal
reference ground for test and measurement.
79
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