ISL6296 Intersil Corporation, ISL6296 Datasheet - Page 10

• Manufacturer Part Number: ISL6296
• Description: FlexiHash
• Manufacturer: Intersil Corporation

XSD Host Bus Interface
Communication with the host is achieved through XSD, a
light-weight subset of Intersil’s ISD single-wire bus interface.
XSD is a programmable-rate pseudo-synchronous
bidirectional host-initiated instruction-based serial
communication interface that allows up to two slave devices
to be attached and addressed separately. It includes
features to enable quick and reliable communication. The
communication protocol is optimized for efficient transfer of
data between the device and the host. The list below
outlines the features supported by the XSD bus interface:
• Programmable bit rate up to 23kbps
• Up to 2 devices can be connected to the host and
• 16-Bit host instruction frame supports multi-Byte register
• Built-in communication error detection
• CRC generation capability
• Supports interrupt signaling
• Integrated bus inactivity detector for automatic activation
XSD BUS PHYSICAL MODEL
The physical model of the XSD bus is shown in Figure 8.
The model shows a single-wire connection between the host
and the device, not including the ground signal. The input
logic on the device side is designed to be compatible with
any voltage between 1.8V to 5.0V. The host interface should
contain an open-drain or open-collector output. The pull-up
resister R
voltage V
the host supply voltage should be used for pull-up.
DATA TRANSFER PROTOCOL
To initiate a transaction, the host first sends a 16-Bit
instruction frame to the device, followed by data byte
frame(s) if the instruction is a write operation. The instruction
frame consists of a chip-select code, operation code,
register bank and address pointer, and number of data bytes
information, as shown in Figure 10. If the instruction is a
read operation, the device will return 1 to 17 byte frames of
data back to the host. The serial data transfer always takes
OTP ROM Write-in-Progress
XSD Bus Error
Register Access Error
addressed separately
read and write
of sleep mode
CONDITION
DDH
PU
can be connected either to the host supply
or the device supply voltage V
ENABLE BIT
INTERRUPT
10
eEEW
(fixed)
eINT
eINT
STATUS FLAG
INTERRUPT
DDD
TABLE 1. INTERRUPT EVENT SUMMARY
sEEW
sACC
sBER
. Typically
ISL6296
Accessing the ISL6296 during an on-going ROM write process (used only
during initial OTP ROM programming).
XSD bus error or invalid instruction frame detected. Improper authentication
sequence detected.
Accessing protected registers.
place with the LSB first. The following explains the bus
symbols and the transaction frames are introduced in later
sections.
BUS SIGNALING SYMBOLS
The XSD bus is nominally held high. Various bus symbols
and commands are generated by active-low pulse width
modulation. Following are the set of valid bus signaling
symbols supported by the XSD interface:
1) break (issued by host):
• used to wake the device up from Sleep mode (Note: a
• used to reset the device’s XSD bit counters and time
• used to signal a change in communication channel (from
2) break (issued by device):
• used as ‘device-ready’ indication to the host (after a
• used as an interrupt indicator
3) ‘1’ symbol:
• used for instruction and data coding
4) ‘0’ symbol:
• used for instruction and data coding
SYMBOL TIMING DEFINITIONS
Symbol timings are defined in terms of bit-time (BT),
determined by the selected bus transfer bit-rate pre-
programmed into the device’s OTP ROM location 0-00[5:4].
Selectable bus speeds are: 2.89kHz (x = 0.5), 5.78kHz
(x = 1), 11.56kHz (x = 2) and 23.12kHz (x = 4).
An instruction or data frame consists of a sequence of ‘1’
and/or ‘0’ symbols. Figure 9 illustrates the timing definitions.
A ‘1’ symbol is nominally 0.3 BT wide while a ‘0’ symbol is
nominally 0.7 BT wide. One ‘1’ or ‘0’ symbol is represented
in each BT period. Any detected pulse width less than 0.124
BT wide will be interpreted as a glitch and will result in a bus
error. Tables 2 and 3 summarize the timing definitions of all
the supported symbols and bus signaling.
narrow ‘break’ can also be used to wake up the device
from the Sleep mode, as described in the Power-on Reset
section)
qualifiers
one slave device to another)
Soft-reset or wake up from Sleep mode)
INTERRUPT EVENT
January 17, 2007
FN9201.1