Onkyo TX-SR502 Service Manual page 18

IC BLOCK DIAGRAM AND TERMINAL DESCRIPTIONS-8
Q701: CS494003CQZ (Multi-Standard Audio Decoder)-2
TERMINAL DESCRIPTION
FILT1 - Phase-Locked Loop Filter
Connects to an external filter for the on-chip phase-locked loop.
FILT2 - Phase Locked Loop Filter
Connects to an external filter for the on-chip phase-locked loop.
CLKIN, XTALI - External Clock Input/Crystal Oscillator Input
CS494003 clock input. This pin accepts an external clock input signal that is used to drive the internal core logic. When in internal clock
mode (CLKSEL == VSS), this input is connected to the internal PLL from which all internal clocks are derived. When in external clock
mode (CLKSEL == VDD), this input is connected to the DSP clock. Alternatively, a 12.288 mhZ crystal oscillator can be connected between
XTALI and XTALO. INPUT
XTALO - Crystal Oscillator Output
Crystal oscillator output. OUTPUT
CLKSEL - DSP Clock Select
This pin selects the internal source clock. When CLKSEL is low, CLKIN is connected to the internal PLL from which all internal clocks are derived.
When CLKSEL is high, the PLL is bypassed and the external clock directly drives all input logic. INPUT
FDAT0~FDAT7 - DSPAB Bidirectional Data Bus
In parallel host mode, these pins provide a bidirectional data bus to DSPAB. These pins have an internal pull-up.
BIDIRECTIONAL - Default: INPUT
FA0, FSCCLK - Host Parallel Address Bit Zero or Serial Control Port Clock
In parallel host mode, this pin serves as one of two address input pins used to select one of four parallel registers. In serial host mode, this pin serves
as the serial control clock signal, specifically as the SPI clock input. INPUT
FA1, FSCDIN - Host Address Bit One or SPI Serial Control Data Input
In parallel host mode, this pin serves as one of two address input pins used to select one of four parallel registers. In SPI serial host mode, this pin serves
as the data input. INPUT
FHS1, FRD, FR/W - Mode Select Bit 1 or Host Parallel Output Enable or Host Parallel R/W
DSPAB control port mode select bit 1. This bit is one of 3 control port select bits that are sampled on the rising edge of RESET to determine the control
port mode of DSPAB. In Intel parallel host mode, this pin serves as the active-low data bus enable input. In Motorola parallel host mode, this pin serves
as the read-high/write-low control input signal. In serial host mode, this pin can serve as the external memory active-low data-enable output signal.
BIDIRECTIONAL - Default: INPUT
FHS0, FWR, FDS - Mode Select Bit 0 or Host Write Strobe or Host Data Strobe
DSPAB control port mode select bit 0. This bit is one of 3 control port select bits that are sampled on the rising edge of RESET to determine the control
port mode of DSPAB. In Intel parallel host mode, this pin serves as the active-low data-write-input strobe. In Motorola parallel host mode, this pin
serves as the active-low data-strobe-input signal. In serial host mode, this pin can serve as the external-memory active-low write-enable output signal.
BIDIRECTIONAL - Default: INPUT
FCS - Host Parallel Chip Select, Host Serial SPI Chip Select
In parallel host mode, this pin serves as the active-low chip-select input signal. In serial host SPI mode, this pin is used as the active-low chip-select input
signal. INPUT
FHS2, FSCDIO, FSCDOUT - Mode Select Bit 2 or Serial Control Port Data Input and Output, Parallel Port Type Select
DSPAB control port mode select bit 2. This bit is one of 3 control port select bits that are sampled on the rising edge of RESET to determine the control
port mode of DSPAB. In SPI mode this pin serves as the data output pin. In parallel host mode, this pin is sampled at the rising edge of RESET to
configure the parallel host mode as an Intel type bus or as a Motorola type bus. BIDIRECTIONAL - Default: INPUT
FINTREQ - Control Port Interrupt Request
Open-drain interrupt-request output. This pin is driven low to indicate that the DSP has outgoing control data that should be read by the host.
OPEN DRAIN I/O - Requires 3.3K Ohm Pull-Up
FSCLKN1, STCCLK2 - PCM Audio Input Bit Clock
Digital-audio bit clock input. FSCLKN1 operates asynchronously from all other DSPAB clocks. In master mode, FSCLKN1 is derived from DSPAB's
internal clock generator. The active edge of FSCLKN1 can be programmed by the DSP.
BIDIRECTIONAL - Default: INPUT
TX-SR502/E/8250/HT-R520