PC87307VUL National Semiconductor, PC87307VUL Datasheet - Page 62

• Manufacturer Part Number: PC87307VUL
• Description: PC87307/PC97307 Plug and Play Compatible and PC97 Compliant SuperI/O
• Manufacturer: National Semiconductor

www.national.com
4.5.4
Once a non-reserved bit is set to 1 it can be cleared only by
hardware (MR pin) reset.
Bit 2-0 - Reserved
Bit 3 - Upper RAM Block
Bit 4 - RAM Block Read
Bit 5 - RAM Block Write
Bit 6 - RAM Mask Write
Bit 7 - RAM Lock
7
0
Reserved.
Controls access to the upper 128 RAM bytes, accessed
via the Upper RAM Address and Data Ports of bank 1
0 - This bit has no effect on upper RAM access.
1 - Upper RAM Data Port of bank 1 is blocked: writes
This bit controls reads from RAM bytes 80h-9Fh (00h-
1Fh of upper RAM).
0 - This bit has no effect on upper RAM access.
1 - Reads from bytes 00h-1Fh of upper RAM return
This bit controls writes to bytes 80h-9Fh (00h-1Fh of up-
per RAM).
0 - This bit has no effect on upper RAM access.
1 - Writes to bytes 00h-1Fh of upper RAM are ignored.
This bit controls writes to all RTC RAM.
0 - This bit has no effect on RAM access.
1 - Writes to bank 0 RAM and to upper RAM are ig-
0 - This bit has no effect on RAM access.
1 - Read and write to locations 38h-3Fh of all banks
6
0
RAM Lock
are ignored and reads return FFh.
FFh.
nored.
are blocked. Writes are ignored, and reads return
FFh.
RAM Lock Register (RLR), Index 47h
5
0
RAM Mask Write
FIGURE 4-14. RAM Lock Register
RAM Block Write
4
0
0
3
RAM Block Read
Real-Time Clock (RTC) and Advanced Power Control (APC) (Logical Device 2)
2
0
0
Upper RAM Block
1
0
0
Reserved
Reserved
0
0
0
Power-Up
Reset
Required
Reserved
RAM Lock
Index 47h
Register
(RLR)
62
4.6 RTC AND APC REGISTER BITMAPS
4.6.1
7
7
7
7
0
0
VRT
SET
6
IRQF
6
6
6
0
0
0
0
0
UIP
RTC Register Bitmaps
PIE
PF
5
5
5
5
DV2
0
1
0
0
0
AF
AIE
DV1
4
4
0
4
0
0
4
0
0
UF
DV0
3
3
0
0
UIE
0
3
0
0
3
0
0
Unused
RS3
2
2
0
2
2
0
0
0
0
Reserved
DM
RS2
1
1
0
1
1
0
0
0
0
Reserved
24 or 12 Hour Mode
RS1
0
0
0
0
0
0
0
0
0
Power-Up
Reset
Required
Power-Up
Reset
Required
Power-Up
Reset
Required
Power-Up
Reset
Required
DSE
RS0
RTC Control
RTC Control
RTC Control
RTC Control
Register D
Register A
Register B
Register C
Index 0Ah
Index 0Bh
Index 0Ch
Index 0Dh
(CRA)
(CRB)
(CRC)
(CRD)