LM12434CIWM NSC [National Semiconductor], LM12434CIWM Datasheet - Page 31

• Manufacturer Part Number: LM12434CIWM
• Description: Sign Data Acquisition System with Serial I/O and Self-Calibration
• Manufacturer: NSC [National Semiconductor]

D15
D15
6 0 Operational Information
CONFIGURATION REGISTER (Read Write)
D0
D1
D2
D3
D4
D5
D6
D7
D9 –D8
D10
D11
D15 –D12 Don’t Care
INSTRUCTION RAM (Read Write)
Instruction
D0
D1
D4–D2
D7 –D5
D8
D9
D10
D11
D15–D12 Acquisition Time Determines S H acquisition time
Acquisition Time
D14
D14
Don’t Care
Start 0 stops the instruction execution 1 starts the instruction execution
Reset When set to 1 resets Start bit also resets all the bits in status registers and resets the instruction pointer to
zero D1 will then automatically reset itself to zero after 2 clock pulses
Auto-Zero When set to 1 a long (8-cycle) auto-zero calibration cycle is performed
Full Calibration When set to 1 a full calibration cycle (linearity and auto-zero) is performed
Standby When set to 1 the chip goes to low-power standby mode Resetting the bit will return the chip to active
mode after a short delay
I S Instruction
result belongs 1
A Z each Cycle When set to 1 a short auto-zero cycle is performed before each conversion
Sync I O 0
RAM Pointer Selects the sections of the instruction RAM 00
This bit is used for production testing and must be kept zero for normal operation
Diagnostic When set to 1 the LM12 L 438 will perform a diagnostic conversion along with a properly selected
instruction This mode is not available on the LM12434
Loop 0
Pause 0
a pause encountered a 1 written to the Start bit restarts the instruction execution
MUXIN
For the LM12434 they select which input channel is connected to MUXOUT
MUXIN
the LM12434 they select which input channel is connected to MUXOUT
Sync 0
(comparison) timing are controlled by an external signal applied to SYNC pin
Timer 0
zero
8 12 0
Watchdog 0
sons
For 12-bit
Where D
For 12-bit
For 8-bit
Where R
D13
D13
FIGURE 9 Bit Assignments for LM12434 and LM12 L 438 Internal Registers (Continued)
b
a
e
e
e
S
e
e
e
For the LM12 L 438 these bits select which input channel is connected to the ADC’s non-inverting input
For the LM12 L 438 these bits select which input channel is connected to the ADC’s inverting input For
a
a
a
e
12-bit
Go to next instruction 1
Timer is not used for this instruction 1
No pause 1
Normal operation internal timing SYNC is an output 1
e
D12
Contents of D15–D12
D12
sign (9
sign Choose D for D
e
sign Choose D for D
Input source resistance
Sync pin is input 1
Conventional conversion (no watchdog comparison) 1
e
a
or extended sign 0
Watchdog
Diag
Bits 13–15 of the result hold the extended sign bit
sign resolution 1
D11
a
D11
2D) clock cycles For 8-bit
e
Pause don’t do the instruction The start bit in the Configuration register resets to 0 when
Test
D10
8 12
D10
e
t
(Continued)
t
e
D9
e
0 45 x R
0 36 x R
Sync pin is output
e
Timer
Loop back to in instruction
Pointer
Bits 13– 15 of the conversion result hold the instruction number to which the
D9
RAM
8-bit
D8
a
S
S
Sync
D8
k
k
sign resolution
e
a
31
Sync
Instruction execution does not begin until timer counts down to
sign (2
I O
c
c
D7
f
f
D7
CLK
CLK
A Z Each
a
MHz
MHz
Cycle
MUXIN
e
D6
2D) clock cycles
D6
Instruction 01
b
0
e
I S
e
D5
D5
b
SYNC is an input S H and conversion
Instruction performs watchdog compari-
a
Stand-
e
D4
by
D4
Limits
MUXIN
Full
Cal
D3
D3
1 10
a
Auto
Zero
D2
D2
e
Limits
Pause
Reset
D1
D1
2
Start
Loop
D0
D0