User guide

7 | P a g e
The H8/H89 “Z67-IDE” DISK CONTROLLER is based on the DS89C430/450 compatible 8051
microcontroller operating at 20MHz. It has a serial port fixed at 9600 bps to download the
firmware and for TTY logs for debugging issues. On power-on the controller searches for both
IDE Master and Slave hard drives. If IDE’s drives are found it will turn-off the SASI error LED,
indicating that it is ready to start communications with the WH-8-37/Z-89-67 card. If any failure
is detected during the IDE scan, the controller will flash the SASI error LED along with the IDE
“I/O” LED, and will stop all communications with the WH-8-37/Z-89-67 card. After the problem
has been resolved, a hard reset via the reset switch or via an AC cycle will cause the controller
to again search for the IDE hard drives.
There is a watchdog timer that monitors the communication between the WH-8-37/Z-89-67
card and the H8/Z-89-67 -IDE controller, and will only reset the H8/H89-Z67-IDE controller
when it detects that communication with the WH-8-37/Z-89-67 has been lost. In this situation it
is recommended to reset the H8 computer via the front panel keyboard and on the H89 via the
H89 keyboard, to boot again from the IDE hard drive. I tested the H8/H89-Z67-IDE Disk
Controller continuously for over 2 months without any issues. The only time the watchdog
timer kick-in was because the IDE power connection failed (bad connection) or due to a poor
IDE cable connections. Refer to Appendix A to see examples of the TTY logs when using IDE,
SATA and CF cards. Also I included TTY logs for a watchdog timeout and when an IDE scan
failed.
A nice feature of the H8/H89 “Z67-IDE” SASI TO IDE DISK CONTROLLER is that once it scans how
many IDE’s drives are present, then it assigns the LUN id’s as follows;
When both Master and Slave drives are present:
IDE MASTER DRIVE
LUN 0
IDE SLAVE DRIVE
LUN 1
When only one drive is present (set as Master or Slave):
N/A
IDE SLAVE DRIVE
LUN 0 AND LUN 1
IDE MASTER DRIVE
LUN 0 AND LUN 1
N/A
This feature allows the controller to re-assign the hard drives LUN’s when only one IDE drive is
present. If a single drive is present (it doesn’t matter if it is a Master or Slave device), it will be
bootable as a Master or Slave device. The user does not need to reconfigure the jumper on the
IDE drive from Slave to Master or vice versa in order to boot the CP/M OS.