MB86604L
(Continued)
Pin
number
50
Symbol*
DMBHE
(DMUDS)
Pin name
DMA bus
high enable
(DMA upper
data strobe)
I/O
I
Function
In the 80-series mode, this pin is for the DMA bus high enable
signal input pin (DMBHE) output from the DMA controller when
the upper byte of the DMA data bus is valid. This is an active-low
pin. In the 68-series mode, this pin functions as the DMA upper
data strobe signal input pin (DMUDS) output from the DMA
controller when the upper byte of data bus is valid. The DMUDS
pin is also an active-low.
In the 80-series mode, this pin is used for the DMA address 0
input pin output from the DMA controller. In the 68-series mode,
a high level should be input to this pin.
This is a DMA transfer permission signal input pin. When this pin
is in active-state, the SPC does the DMA transfer. In case that
this pin becomes inactive during the DMA transfer, the DMA
transfer is paused on the block boundary. This pin is an active
high.
30
DMA0
DMA
address 0
Transfer
permission
I
55
TP
I
* : The pin symbols in parenthesis are the ones when the MODE input is “L”.
4. Others
Pin
number
6
5
3, 14, 28
53, 64, 78
4, 10, 15
16, 21, 29
40, 54, 59
65, 66, 70
79, 90
23
Symbol*
RESET
CLK
V
DD
V
SS
Pin name
Reset
Clock
Power supply
Ground
I/O
I
I
—
—
Function
System reset input pin. The input reset active pulse width must
have 4 times of the clock cycle at least. This is an active-low pin.
Clock signal input pin. 20 MHz, 30 MHz, or 40 MHz can be
applied as the input clock frequency.
+5 V power supply pins.
Ground pins.
TEST1
TEST
I
This pin is used to select the type of I/O buffer on SCSI data bus
pins. In case that DBP DB7 – DB0 pins are used as an open-
,
drain I/O, connect this pin to V
SS
. In case of three-state I/O,
connect to V
DD
.
This pin is used to select the type of I/O buffer on SCSI pins. In
case that MSG, C/D, I/O, and ATN pins are used as an open-
drain I/O, connect this pin to V
SS
. In case of three-state I/O,
connect to V
DD
.
This is a SCSI Timeout pin that indicates the SPC has been
busy longer than the specified time. A high level is output on this
pin if the SPC busy time exceeds the specified time.
This pin can be used for the timeout counter.
These are open pins. Those pins are not connected with the
device internally. Those pins must be left open.
57
TEST2
TEST
I
24
TMOUT
TIMEOUT
O
25, 26
(OPEN)
(Open)
—
* : The pin symbols in parenthesis are the symbols when the MODE input is “L”.
7
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