E7804BHF Semtech, E7804BHF Datasheet - Page 10

• Manufacturer Part Number: E7804BHF
• Manufacturer: Semtech

Specifications of E7804BHF

• Operating Temperature (max): 100C
• Package Type: MQFP
• Mounting: Surface Mount
• Lead Free Status / Rohs Status: Not Compliant

Read/Write: 1 bit
This determines whether a particular address/function is
being written or read. (Note that some functions are read-
only or write-only).
Function: 4 bits
This determines which function within a channel or set is
being set or read.
Refer to Figure 2 for a block diagram of the Write and
Read logic for the serial programming. The serial data is
input into the device SDIN pin. The data at SDIN is clocked
in on the high-going edge of the CLKIN input signal. The
data at the SDOUT pin is clocked out on the low-going
edge of the CLKIN input signal for ease of “daisy chaining”
multiple devices.
RESET*
There is a single input pin to the entire Edge7804 chip
that will clear all on-chip registers and open all on-chip
switches. This input pin, RESET*, is active low and is
asynchronous, not requiring any CLKIN transitions to
operate. It is advised that, upon power-up in a system,
this pin is either held low or cycled low for a brief time
while the system and power supplies become stable in
TEST AND MEASUREMENT PRODUCTS
Circuit Description (continued)
2005 Semtech Corp. / Rev. 5, 12/6/05
0 = write a control/data register
1 = read back the contents of a register
RESET*
CLKIN
LOAD
SDIN
Figure 2. Block Diagram of Read and Write Shift Registers
SIN
D[20:24]
CK
DATA
13
24-Bit Shift Register
24-Bit Shift Register
RESET
RESET
RESET
D[5:17]
READBACK
LATCH
WRITE
10
DATA
ADR
Q
10
24
order to put the Edge7804 into a known starting state.
After power-up, the RESET* may be exercised or a soft
reset instruction may be programmed.
Write Serial Data
Data is shifted into the WRITE shift register using CLKIN.
The data stored in the shift register will be stored into the
Edge7804 by asserting the LOAD input signal during the
24
instruction inside the Edge7804 for address decoding and
data storage into the appropriate on-chip registers.
Seven (7) more CLKIN high-going edges should be
given after a LOAD for full decode and all instruction
executions.
Refer to Figure 3 for a timing diagram of the writing
operation. Notice that the SDOUT data that is clocked out
on the low-going edge of CLKIN is a bit for bit representation
of the data that had been shifted into the Edge7804 24
clock edges beforehand. This echoing of the data allows
the user to “daisy chain” multiple Edge7804 devices to
minimize the number of serial data streams that need to
be implemented. The compromise is the length of time it
takes to clock through all the 24-bit instructions for all
the devices in the chain.
D[0:4]
th
READBIT
Read Bit Only True
"Don't Care"
CLKIN high-going edge. The LATCH will hold the
for 24 Clocks
SOUT – READ
SOUT – WRITE
SDOUT
Edge7804
PRELIMINARY
www.semtech.com