Casio MP-2000 Service Manual page 58

Name Number
Floppy Disk interface
WDATAJ 9
HDSELJ 11
DIRJ 7
STEPJ 8
DSKCHGJ 17
DSOJ, 4, 3
DSIJ
PDIR 99
A10 97
MTROJ, 2, 5
MTR1J
DACKB 96
DRQB 98
DENSEL 1
WRTPRTJ 14
TRK0J 13
INDEXJ 12
UR1IRQB 18
DRATE0 19
Serial Port Interface
RXD1, 78,88
RXD2
TXD1, 79
PCF0
Type Description
O36 Write Data. This active low output is a write- precompensated serial data to be
written onto the selected disk drive. Each falling edge causes a flux change on
the media.
O36 Head Select. This active low output determines which disk drive head is active.
Low=Head 0, high (open) = Head 1.
O36 Direction. This active low output determines the direction of the head
movement (low = step-in, high = step-out). During the write or read modes, this
output is high.
O36 Step. This active low output produces a pulse at a software-programmable rate
to move the head during a seek operation.
IS Disk Change. This disk interface input indicates when the disk drive door has
been opened. This active-low signal is read from bit D7 of address xx7h.
O36 Drive Select 0, 1. Active low, output select drives 0-1.
O36 This bit is used to indicate the direction of the Parallel port data bus. 0=
output/write, 1= input/ read.
I This pin is the A10 address input.
O35 Motor on 0, 1. These active low outputs select motor drives 0-1.
I This signal is the Parallel port DMA acknowledge input.
O36 In ECP mode, This is the Parallel Port DMA Request output active high signal.
O36 Density select. This signal indicates whether a low (250/300 kbps) or high
(500 kbps) data rate has been selected. This is determined by the DENSEL bits
in Configuration register 5.
IS Write Protected. This active-low Schmitt Trigger input senses from the disk
drive that a disk is write-protected. An write command is ignored.
IS Track 00. This active low Schmitt Trigger input senses from the disk drive that
the head is positioned over the outermost track.
IS Index. This active low Schmitt Trigger input senses from the disk drive that the
head is positioned over the beginning of a track, as marked by an index hole.
I/O36 Serial Port Interrupt Request. Alternate IRQ output from UART1, refer to CRO
bit 6.
I/O36 Data Rate 0. This output reflects bit 0 of the Data Rate Register. At power on,
this output is in a high impedance state.
I Receive Data. Receiver serial data input.
O4 Transmit Data. Transmitter serial data output from Primary Serial Port.
Parallel Port configuration control 0. During reset active, this input signal is
read and latched to define the address of the Parallel port.
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