W88113C Datasheet, PDF (45/102 Pages) Winbond – ATAPI CD-ROM DECODER & CONTROLLER

W88113C
MISC0 - Miscellaneous Control Register 0 - (write 2Eh)
Bit 7: HIIEN - Host Interface Interrupt Enable
Setting this bit high enables the microprocessor interrupt of the host interface. Host interface
interrupt occurs at the following conditions:
• SRST (Device Control Register) is written as 1 after 0 to either master or slave drive.
• Execute Drive Diagnostics Command is written to either master or slave drive.
• Any opcode is written to the ATAPI Command Register while the drive is selected except:
(1) command opcode is 08h, (2) command opcode is A0h and APKTEN (18h.7) is high.
IDE interface interrupt is cleared by the following:
• Chip reset or host reset
• Reading register 37h
• Writing 1 to CLRBSY (20h.4)
Bit 6: Reserved
Bit 5: DRVEb - Drive Selection Enable
Setting this bit low enables selection of the drive if bit DRV in ATAPI Drive Select Register
matches the setting of MDRV (2Eh.4).
Bit 4: MDRV - Master Drive
Setting this bit high sets the drive to be selected when bit DRV in the ATAPI Drive Select
Register is set to 0 (Master Drive).
Bit 3 : HIRQ - Host Interrupt Request
Set this bit high asserts interrupt at pin HIRQ if the drive is selected and nIEN is enabled in
the ATAPI Device Control Register. HIRQ is also automatically set by the following:
• Automatic Packet Transfer sequence, enabled by APKTEN (18h.7)
• Automatic Status Completion sequence, enabled by SCT (17h.w0) or ASCEN (18h.5)
HIRQ is automatically de-activated by the following:
• Chip reset or host reset
• Set bit SRST in the ATAPI Device Control Register high
• Host issue ATA command while the drive is selected
• Host read ATAPI Status Register while the drive is selected
Bit 2: SHIEN - Shadow Command Interrupt Enable
Setting this bit high enables the microprocessor interrupt for the shadow command. Pin
UINTb (36) becomes low-active when SHDC (2Fh.r5) becomes high-active if this bit is
enabled.
Bit 1, 0: Reserved
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Publication Release Date: Mar. 1999
Revision 0.61