This PCB handles the following functions:
RS232 communication with the PW338
iPod RS232 control (compatible with rLead & rDock)
Sirius satellite radio (US)
Z1, Z2, Z3 12V triggers
DAB
AM/FM
Z1, Z2, Z3 IR inputs.
CON102 & IC102 (MAX3232 RS232 converter, part1) provide the RS232
communication with the PW338 – used for RS232 control or updating. Note,
the signals RS232 Tx & RS232 Rx are labelled relative to the PW338, so
RS232 Tx is the Tx FROM the PW338.
CON105 & IC102 (MAX3232 RS232 converter, part2) provide the iPod RS232
communication. Pin 9 of CON105 (/iPod Present to PW338) is taken low
when an rLead is connected. Note, the signals iPod Tx & iPod Rx are
labelled relative to the UART (IC403, L122), so iPod Tx is the Tx FROM the
UART.
SKT101 provides the Sirius RS232 communication. Note, the signals Sirius
Tx 232 & Sirius Rx 232 are labelled relative to the UART (IC403, L122), so
Sirius Tx 232 is the Tx FROM the UART.
SKT101 also provides the +5V for the Sirius Home Connect module, so the
module does not require external power. This power comes from the +5V_1
(L123) and is connected to pins 1 & 2 of SKT101 as power & host presence.
Analogue audio also passes through this socket, so this is the only connection
to the Sirius module.
There are three triggers, Zone1 , Zone 2, Zone 3. These give a 12V 100mA
output when activated from IC101 (74HC595 serial to parallel converter). The
signals Z1 Trig, Z2 Trig & Z3 Trig are active high.
DAB uses the Gyrosignal 1122 module. As this module is normally controlled
via RS232, a CPLD, IC100 (XC95C36 Xilinx) is used to provide I2C control
from the PW338 (DAB SCL & DAB SDA). Due to an issue with the
Gyrosignal implementation of I2C within their CPLD, IC103 (SN74HC1GU04
single inverter) is required to invert the DAB SCL signal. The DAB module
gives an analogue output which is buffered through a ground balancing circuit
(IC301 NJM2114 op amp) – this section is also used for the Sirius analogue
output. DAB /RESET comes from IC101 (74HC595).
AM/FM uses the ALPS module. Different modules are fitted depending on
region – Europe (with RDS), US (no RDS), Japan (different FM range).
Control is direct from the PW338, FM CE, SPI Data, SPI Clk. Also, /RDS On
from IC101 (74HC595) is used to turn off the RDS chip in EU modules when
the AM band is used (the RDS chip running on AM interferes with AM
performance). RDS Int & Data come from the Alps module to the PW338 for
L118AY – IR – Trig – DAB/FM - RS232
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