PRELIMINARY DATA SHEET
MSP 34x1G
Pins 71, 72 XTAL_IN, XTAL_OUT – Crystal Input and
Output Pins (Fig. 4–20)
These pins are connected to an 18.432 MHz crystal
oscillator which is digitally tuned by integrated shunt
capacitances. An external clock can be fed into
XTAL_IN. The audio clock output signal AUD_CL_OUT
is derived from the oscillator. External capacitors at
each crystal pin to ground (AVSS) are required. It
should be verified by layout, that no supply current for
the digital circuitry is flowing through the ground con-
nection point.
Pin 73, TP – This pin enables factory test modes. For
normal operation, it must be left vacant.
Pin 74, AUD_CL_OUT – Audio Clock Output
(Fig. 4–20)
This is the 18.432 MHz main clock output.
Pins 75, 76, NC – Pins not connected.
Pins 77, 78, D_CTR_I/O_1/0 – Digital Control Input/
Output Pins (Fig. 4–19)
General purpose input/output pins. Pin D_CTR_I/O_1
can be used as an interrupt request pin to the control-
ler.
Pin 79, ADR_SEL – I2C Bus Address Select
(Fig. 4–17)
By means of this pin, one of three device addresses for
the MSP can be selected. The pin can be connected to
ground (I2C device addresses 80/81hex), to +5 V sup-
ply (84/85hex), or left open (88/89hex).
Pin 80, STANDBYQ – Stand-by
In normal operation, this pin must be high. If the
MSP 34x1G is switched off by first pulling STANDBYQ
low and then (after >1µs delay) switching off DVSUP
and AVSUP, but keeping AHVSUP (‘Standby’-mode),
the SCART switches maintain their position and func-
tion.
* Application Note:
All ground pins should be connected to one low-resis-
tive ground plane. All supply pins should be connected
separately with short and low-resistive lines to the
power supply. Decoupling capacitors from DVSUP to
DVSS, AVSUP to AVSS, and AHVSUP to AHVSS are
recommended as closely as possible to these pins.
Decoupling of DVSUP and DVSS is most important.
We recommend using more than one capacitor. By
choosing different values, the frequency range of
active decoupling can be extended. In our application
boards we use: 220 pF, 470 pF, 1.5 nF, and 10 µF. The
capacitor with the lowest value should be placed near-
est to the DVSUP and DVSS pins.
The ASG pins should be connected as closely as pos-
sible to the MSP ground. If they are lead with the
SCART-inputs as shielding lines, they should not be
connected to ground at the SCART connector.
Micronas
55
MICRONAS [ MICRONAS ]
