CS5460A
DS284PP4
31
‘LSD’ status bit in the Mask Register (the purpose
for this action is described in section ). Finally, the
EEPROM code will initiate ‘continuous computa-
tion cycles’ data acquisition mode and select one of
the alternate pulse-output formats (e.g., set the
MECH bit in the Control Register). The serial data
for such a sequence is shown below in single-byte
hexidecimal notation:
40 00 00 61
;In Configuration Register,
turn high-pass filters on, set
K=1.
44 7F C4 A9
;Write value of 0x7FC4A9 to
Current Channel Gain Regis-
ter.
46 7F B2 53
;Write value of 0x7FB253 to
Voltage Channel DC Offset
Register.
4C 00 00 14
;Set Pulse Rate Register to
0.625 Hz.
74 00 00 04
;Unmask bit #2 (“LSD” bit in
the Mask Register).
E8
;Start performing continuous
computation cycles.
78 00 01 40
;Write STOP bit to Control
Register, to terminate au-
to-boot
initialization
se-
quence, and also
set the
EOUT pulse output to Me-
chanical Counter Format.
This data from the EEPROM will drive the SDI pin
of the CS5460A during the auto-boot sequence.
The following sequence of user-controlled events
will cause the CS5460A to execute the auto-boot
mode initialization sequence: (A simple timing dia-
gram for this sequence is shown below in
Figure 14.) If the MODE pin is set to logic high (or
if the MODE pin was set/tied to logic high dur-
ing/after the CS5460A has been powered on), then
changing the RESET pin from active state to inac-
tive state (low to high) will cause the CS5460A to
drive the CS pin low, and after this, to issue the stan-
dard EEPROM block-read command on the
CS5460A’s SDO line. Once these events have com-
pleted, the CS5460A will continue to issue SCLK
pulses, to accept data/commands from the EE-
PROM. The serial port will become a master-mode
interface. For a more detailed timing diagram, see
SWITCHING CHARACTERISTICS (in Section 1.)
4.3.3 Which EEPROMs Can Be Used?
Several industry-standard serial EEPROMs that
will successfully run auto-boot with the CS5460A
are listed below:
•
Atmel
AT25010
AT25020
AT25040
•
National Semiconductor
NM25C040M8
NM25020M8
•
Xicor
X25040SI
RES
CS
SCLK
SDO
SDI
EE Read
Address 0
5460A
Commands
Stop
MODE
Figure 14. Timing Diagram for Auto-Boot Sequence
Содержание CS5460A
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