Kenwood DP-3010 Service Manual page 26

DP-3010
CIRCUIT DESCRIPTION
2) Write Command Input Mode
This mode transmits the Write Command and Four-Word
Data (CM-A)-(CM-D) from the CPU to TC9201BF. The first
two words are Commands (C6 ~ CO) and the next two
words are the Data (D7-D0}.
TC9201BF takes in the Command or Data of the BUS from
the BUCK trailing edge and will then Echo Back the con-
tent on the BUS when BUCK is "H". Therefore, it is possible
to confirm whether the Command or Data has been cor-
rectly received by checking the BUS 0-3 condition at
BUCK Trailing Edge (since the BUS line is Wired OR, Error
Detection during "L" is not possible).
When a Write Command is input, it is synchronized to the
BUCK trailing edge (Actually, the DA/CO and the CPU in-
formation is delayed by 4 ys after the BUCK trailing edge.
More than 4 us More than 4 us
BUCK
DA/CO
BUS3
BUS2
The same dela, 's needed in the Lead Command input}
Also, when a Write Command is input. the first word of
the command B_S 3 is "H" tevel, while the DA/CO line be-
comes "L" (Command Transmission Start). When the
second Command and Data word are correctly received.
TC9201BF will return the ACK acknowledge signal, on the
DA/CO Line (wren the Write Command is correctly input
and reception ts complete, DA/CO Line is "L" Level).
When this ACK 's returned, the BUS line switches from
Command Inpui Mode to Idle Mode again.
Hf the ACK is no* -eturned, this means that there is Recep-
tion Error, so the Command is sent again. This is same for
a Read Commanz too.
When Write information
transmission/reception is OK,
the ""L" Level
Diagram 7-3 Write Command Input Example
DP-3010
CIRCUIT DESCRIPTION
3) Read Command Input Mode
In this mode, when a one-word Read Command (SORD
and STRD Command} from the CPU is transmitted,
TC9201BF sends the designated data back through the
BUS line. The handling of the BUCK and Commands are
same as in Write Mode, but in Read Mode, but when a
command is input, BUS 3 line is "L" level whiie the DA/CO
More than 4 zs More than 4 us
BUCK
DA/CO
BUS3
BUS2
line is "L" level at the same time. Therefore, whether the
first word on the BUS 3 line is "H" or "L" differentiates be-
tween a Write and Read Command.
When the transmission/reception of the desiganated data
is complete, an ACK signal is returned to the CPU where
the BUS line then switches to Idle Mode.
When Read information
transmission 'reception is OK,
the "L" Level
Bust Sa eae
BUSO
Read Data
Diagram 7-4 Read Command Input Example
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