MEC1322 Datasheet, PDF (135/456 Pages) Microchip Technology – Keyboard and Embedded Controller for Notebook PC

MEC1322
ACPI-OS DATA BYTES[3:0]
Writes by the ACPI_OS to the ACPI-OS DATA BYTES[3:0] are aliased to the OS2EC DATA BYTES[3:0]. Reads by the
ACPI_OS from the ACPI-OS DATA BYTES[3:0] are aliased to the EC2OS DATA BYTES[3:0].
All access to the ACPI-OS DATA BYTES[3:0] registers should be orderly: Least Significant Byte to Most Significant Byte
when byte access is used.
Writes to any of the four ACPI-OS DATA BYTES[3:0] registers clears the CMD bit in the OS STATUS OS Register (the
state of the FOUR_BYTE_ACCESS bit in the OS Byte Control Register has no impact.)
When the FOUR_BYTE_ACCESS bit in the OS Byte Control Register is cleared to ‘0’, the following access rules apply:
1. Writes to the ACPI OS Data Register Byte 0 Register sets the IBF bit in the OS STATUS OS Register.
2. Reads from the ACPI OS Data Register Byte 0 Register clears the OBF bit in the OS STATUS OS Register.
3. All writes to ACPI-OS DATA BYTES[3:1] complete without error but the data are not registered.
4. All reads from ACPI-OS DATA BYTES[3:1] return 00h without error.
5. Access to ACPI-OS DATA BYTES[3:1] has no effect on the IBF & OBF bits in the OS STATUS OS Register.
When the Four Byte Access bit in the OS Byte Control Register is set to ‘1’, the following access rules apply:
1. Writes to the ACPI OS Data Register Byte 3 Register sets the IBF bit in the OS STATUS OS Register.
2. Reads from the ACPI OS Data Register Byte 3 Register clears the OBF bit in the OS STATUS OS Register.
10.12.2 ACPI OS DATA REGISTER BYTE 1 REGISTER
This register is aliased; see ACPI-OS DATA BYTES[3:0] on page 135, OS2EC DATA BYTES[3:0] on page 141, and
EC2OS DATA BYTES[3:0] on page 142 for detailed description of access rules.
Offset ^01h
Bits
Description
7:0 ACPI_OS_DATA_BYTE_1
This is byte 1 of the 32-bit ACPI-OS DATA BYTES[3:0].
Type
R/W
Default
0h
Reset
Event
VCC1_R
ESET
10.12.3 ACPI OS DATA REGISTER BYTE 2 REGISTER
This register is aliased; see ACPI-OS DATA BYTES[3:0] on page 135, OS2EC DATA BYTES[3:0] on page 141, and
EC2OS DATA BYTES[3:0] on page 142 for detailed description of access rules.
Offset ^02h
Bits
Description
7:0 ACPI_OS_DATA_BYTE_2
This is byte 2 of the 32-bit ACPI-OS DATA BYTES[3:0].
Type
R/W
Default
0h
Reset
Event
VCC1_R
ESET
10.12.4 ACPI OS DATA REGISTER BYTE 3 REGISTER
This register is aliased; see ACPI-OS DATA BYTES[3:0] on page 135, OS2EC DATA BYTES[3:0] on page 141, and
EC2OS DATA BYTES[3:0] on page 142 for detailed description of access rules.
Offset ^03h
Bits
Description
7:0 ACPI_OS_DATA_BYTE_3
This is byte 3 of the 32-bit ACPI-OS DATA BYTES[3:0].
Type
R/W
Default
0h
Reset
Event
VCC1_R
ESET
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DS00001719D-page 135