Operational Characteristics
LANCAM B Family
Table 3: Device Control State After Reset
CAM Status
/RESET Condition
Validity bits at all memory locations
Match and Full Flag outputs
Skip = 0, Empty = 1 (empty)
Enabled
IEEE 802.3–802.5 Input Translation
CAM/RAM Partitioning
Comparison Masking
Not translated
64 bits CAM, 0 bits RAM
Disabled
Address register auto-increment or auto-decrement
Source and Destination Segment counters count ranges
Address register and Next Free Address register
Page Address and Device Select registers
Control register after reset (including CT15)
Persistent Destination for Command writes
Persistent Source for Command reads
Persistent Source and Destination for Data reads and writes
Operating Mode
Disabled
00B to 11B; loaded with 00B
Contain all 0s
Contain all 0s (no change on software reset)
Contains 0008H
Instruction decoder
Status register
Comparand register
Standard
Configuration Register set
Foreground
Page Address Register (PA)
The Page Address register is loaded using a TCO PA
instruction followed by a Command Write cycle of a user
selected 16-bit value (not FFFFH). The entry in the PA
register gives a unique address to the different devices in a
daisy chain. In a daisy chain, the PA value of each device
is loaded using the SFF instruction to advance to the next
device, shown in the Setting Page Address Register Values
on page 16. A software reset (using the Control register)
does not affect the Page Address register.
Control Register bits CT3 and CT2 set the Address
register to automatically increment or decrement (or not
change) during sequences of Command or Data cycles.
The Address register changes after executing an
instruction that includes M@[AR] or M@aaaH, or after a
data access to the end limit segment (as set in the Segment
Control register) when the persistent source or destination
is M@[AR] or M@aaaH.
Either the Foreground or Background Address register is
active, depending on which register set is selected, and
only the active Address register is written to or read from.
Device Select Register (DS)
The Device Select register selects a specific (target)
device. The TCO DS instruction sets the 16-bit DS register
to the value of the following Command Write cycle. The
DS register can be read. A device is selected when its DS
is equal to its PA value. In a daisy chain, setting DS =
FFFFH selects all devices. However, in this case, the
ability to read information out of the device is restricted as
shown in Table 4. A software reset (using the Control
register) does not affect the Device Select register.
Next Free Address Register (NF)
The LANCAM automatically stores the address of the first
empty memory location in the Next Free Address register,
which is then used as a memory address pointer for
M@NF operations. The Next Free Address register,
shown in Next Free Address Bits on page 24, can be read
using a TCO NF instruction. By taking /EC LOW during
the TCO NF instruction cycle, only the device with /FI
LOW and /FF HIGH outputs the contents of its Next Free
Address register, giving the Next Free address in a system
of daisy-chained devices. The Next Free address may be
read from a specific device in the chain by setting the
Device Select register to the value of the desired device’s
Page address and leaving /EC HIGH. The Full Flag daisy
chain causes only the device whose /FI input is LOW and
/FF output HIGH to respond to an instruction using the
Next Free address. After a reset, the Next Free Address
register is set to zero.
Address Register (AR)
The Address register points to the CAM memory location
to be operated upon when M@[AR] or M@aaaH is part of
the instruction. It can be loaded directly by using a TCO
AR instruction or indirectly by using an instruction
requiring an absolute address, such as MOV aaaH,CR,V.
After being loaded, the Address register value is the next
memory access referencing the Address register. A reset
sets the Address register to zero.
Rev. 5.1
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