Sony AN-101 Service Manual page 11

ICF-SW1
AN-101
SYMBOL NAMING DESCRIPTION
PB3 PORT B 4-bit exclusive output ports.
| For ports PBO and PB1, the sink current is minimized to a specially-low drain, so the PBO
PBO and PB1 are able to be used as the return-signal sources for the key matrix. Accordingly,
any of the reverse-current-preventive diodes can be eliminated when these PBO and PB1
ports are used as the key-return-signal sources. When these ports are used as ordinal output
ports, it will happen any of the low-level output signal will not be output properly depend-
ing upon the circuit employed, because of the low sink current. In these cases, pull-down
resistors are used in these output lines.
Under the port-operation commands like "IN", "OUT", "SOB", "RPB" commands, etc.,
the PAO port coincides with the least significant bit of the registor or the operand, the PA3
coincides with the most-significant bit of them. The same applies to the Port B and Port C
respectively. These exclusive output ports should be initialized using the programmes, be-
cause these ports output unstable and undefined output signals at the initial power-on con-
dition, i.e., from '""L" to "H"'.
The output-data contents are the same as these previous last ones when the CE terminal
changes from "L" to "H" or from "H" to "L", and when the CKSTP commands are under
execution. Accordingly, the initialization with programmes is needed too where required.
In this set, these ports are used as those shown in the parenthesises.
PB3 First local frequency control: In LW and MW (in 9 kHz step), if 3 is left when the receiving
(3 kHz) frequency divided by 6, it outputs "L" (low). If divisible by 6, outputs "H" (high).
PB2 First local frequency control: In MW (in 10 kHz step) and SW, if 5 is left when the receiving
(5 kHz) frequency divided by 10, it outputs "L" (low). If divisible by 10, outputs "H" (high).
PB1 Key matrix key lease signal.
PBO
PORT C Refer to the PORT B outlined above. All the ports of this PORT C apply to the description
(KEY- for the PORT B.
MATRIX In this set, these ports output signals to be used as the signal sources for the key matrix.
SIGNAL-
SOURCE
OUTPUT)
This is a free terminal and is not connected to the internal circuits, and this terminal can be
used as a junction land.
Refer to description for pins 38 through 40 outlined above.
KEY 4-bit exclusive input ports. These are normally used as the key-matrix input terminals.
INPUTS When the KIN or the KI commands executed, the conditions of these pins are read into the
RAM data memories designated by the operand portion of these commands.
Same as pin 20.
Same as pins 43 through 45.
Same as pins 1 through 10.
Same as pin 41.
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