W83977AF Information Storage Devices, Inc, W83977AF Datasheet - Page 142

• Manufacturer Part Number: W83977AF
• Description: W83877TF Plus Kbc, Cir, RTC
• Manufacturer: Information Storage Devices, Inc

10.6 Logical Device 4 (Real Time Clock)
CR30 (Default 0x01 when PENKRC=1 at POR)
CR31
CR60, CR 61 (Default 0x00, 0x70 when PENKRC=1 at POR)
CR70 (Default 0x08 when PENKRC=1 at POR)
CR71 (Default 0x00, read/write)
CRF0 (Default 0x00)
Note : Once set, bit[3:0] can not be cleared by a write; bit[3:0] is cleared only on Power-On Reset or upon a Hard Reset.
Bit 7-1 : Reserved.
Bit 0 :
Bit 7-2 : Reserved.
Bit 1 : ENRNGCK -- > Enable I/O Range check
Bit 0 : FORIORD --> Forces LDN to respond I/O read
These two registers select Real Time Clock I/O base address [0x100:0xFFE] on 2 byte
boundaries.
Bit 7-4 : Reserved.
Bit [3:0] : These bits select IRQ resource for RTC.
Bit 7-2 : Reserved.
Bit 1 : IRQLEV -- > IRQ Level
Bit 0 : IRQTYPE --> IRQ Type
RTC Mode Register
Bit 7-6 :
Bit 5-4 : Reserved.
Bit 3 : = 1 Lock CMOS RAM E0-FFh
Bit 2 : = 1 Lock CMOS RAM C0-DFh
Bit 1 : = 1 Lock CMOS RAM A0-BFh
Bit 0 : = 1 Lock CMOS RAM 80-9Fh
= 1 Activates the logical device.
= 0 Logical device is inactive.
= 1: High; = 0: Low
= 1: Level trigger; = 0: Edge trigger
= 00 Select BANK0 of RAM
= 01 Select BANK1 of RAM
= 10 Select BANK2 of RAM
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W83977F/ W83977AF
Publication Release Date: March 1998
PRELIMINARY
Revision 0.58