Dell Indexed IO (Type 212)

Source: Dell libsmbios, src/include/smbios_c/obj/token.h.

Describes tokens, which are stored in CMOS and accessed through the indexed I/O ports, and the checksum of the CMOS area.

Table 1. Dell Indexed IO structure
Offset	Version	Name	Length	Value	Description
`0x00`	2.0+	Type	`BYTE`	`212`	Dell Indexed IO indicator
`0x01`	2.0+	Length	`BYTE`	Varies	Length of the structure
`0x02`	2.0+	Handle	`WORD`	Varies
`0x04`	2.0+	Index Port	`WORD`	`ADDRESS`	I/O port used to select the CMOS location
`0x06`	2.0+	Data Port	`WORD`	`ADDRESS`	I/O port used to access the selected CMOS location
`0x08`	2.0+	Checksum Type	`BYTE`	`ENUM`	See Checksum types for details
`0x09`	2.0+	Checked Range Start Index	`BYTE`	`NUMBER`	First CMOS index of the checked range
`0x0A`	2.0+	Checked Range End Index	`BYTE`	`NUMBER`	Last CMOS index of the checked range
`0x0B`	2.0+	Checksum Value Index	`BYTE`	`NUMBER`	CMOS index of the checksum value. If the checked range and the checksum index are all zeroes, there is no checksum.
`0x0C`	2.0+	Tokens	Varies	Varies	Tokens, see Tokens. The table is terminated by a token with ID `0xFFFF`, tokens with ID `0x0000` are unused.

1. Dell Indexed IO — Tokens

Table 2. Dell Indexed IO: Token
Offset	Name	Length	Value	Description
`0x00`	Token ID	`WORD`	`NUMBER`
`0x02`	Location	`BYTE`	`NUMBER`	CMOS index of the token value
`0x03`	AND Mask	`BYTE`	`NUMBER`	Mask applied to the value at the location. Zero for string tokens.
`0x04`	OR Value / String Length	`BYTE`	`NUMBER`	For boolean tokens, value set at the location when the token is activated. For string tokens, length of the string.

2. Dell — Checksum types

Table 3. Dell: Checksum type field
Hex Value	Dec Value	Meaning
`0x00`	`0`	Running sum in a word
`0x01`	`1`	Running sum in a byte
`0x02`	`2`	CRC in a word
`0x03`	`3`	Running sum in a word, then negated (`~sum + 1`)