Yamaha Mio, Service Manual

Page: 64 / 73

Software Description
In order for the MIO to perform its multitude of tasks, one full page of memory has been allocated for
general operating variables and configuration parameters. Two other pages have been reserved for
"R:" handler input and output buffers, and the rest of memory (up to 4093 pages) can be used as
RAM drives and a printer buffer through the MIO ROM. Table 5-4 describes the configuration
parameters (those which are read from the hard disk (ID=0, LUN=0) when memory is invalid). This
table occupies the first 192 bytes of memory page 0. The remaining 64 bytes are operating variables
and are listed in table 5-5. Memory pages 1 and 2 are reserved for the "R:" handler input/output
buffers.
Table 5-4. MIO Configuration Parameters
Address
(HEX)
Symbol
Name
Length
(Dec)
Function of parameter or variable.
$D600 MEMKEY 16 This contains a string of characters. If the string in memory is
not equal to that in ROM, it is assumed that power to the MIO
has been lost and it should reconfigure.
$D610 DRDATA 64 This contains an array of 8 drive config records (each 8 bytes
long). Records are:
+0: First physical block address (sector number) of logical
device. MSB first.
+3: Last+1 physical block address (sector number) of logical
device. MSB first.
+6: B[2,0] = SCSI/SASI ID if hard disk
= drive number if floppy
B[5] = 1 if floppy drive (reassign)
B[6] = 1 if RAM drive
B[7] = 1 if Hard drive
if B[7,5] = 0, then ignore
+7: B[3] = 1 if disk is write locked
B[4] = 1 if SASI type interface
B [7,5] = logical unit number of drive
$D652 PREND 2 Last+1 RAM page number allocated to print spooler.
$D654 PRUNIT 1 Printer device number (0 if P: disabled)
$D655 PRFLAGS 1 Printer configuration flags
B[5] = 1 if using a serial printer
B[6] = 1 if spooler is enabled
B[7] = 1 if CR/LF option enabled
$D656 SERUNIT 1 RS-232 "R:" enable flag; 1=enable/0=disable
$D657 SERFLAGS 1 Default configuration for serial port.
B[7] = 1 if to append LF after CR
B[6] = 1 if 2 stop bits (else 1 stop bit)
B[5] = 1 if no ATASCII/ASCII translation
B[4,3] = parity mode: 00=none, 01=odd, 10=even, 11=mark
B[2,0] = baud rate index
$D658 RAMUSAGL 8 Number pages allocated for each drive (low)
$D660 RAMUSAGH 8 Number pages allocated for each drive (hi)
MIO Service Manual Page 63