Linduino  1.3.0
Linear Technology Arduino-Compatible Demonstration Board

LTC2666: 8-Channel SPI 16-/12-Bit +/-10V Vout SoftSpan DACs with 10ppm/C Max Reference. More...

Detailed Description

LTC2666: 8-Channel SPI 16-/12-Bit +/-10V Vout SoftSpan DACs with 10ppm/C Max Reference.

The LTC2666 is a family of 8-channel, 12/16-bit +/-10V digital-to-analog converters with integrated
precision references. They are guaranteed monotonic and have built-in rail-to-rail output buffers.
These SoftSpan DACs offer five output ranges up to +/-10V. The range of each channel is independently
programmable, or the part can be hardware-configured for operation in a fixed range.

The integrated 2.5V reference is buffered separately to each channel; an external reference can be used
for additional range options. The LTC2668 also includes toggle capability - alternating codes via the
software toggle command, or by providing a free-running clock to the TGP pin.

The SPI/Microwire-compatible 3-wire serial interface operates on logic levels as low as 1.71V, at clock
rates up to 50MHz.


 SPI DATA FORMAT (MSB First):

 24-Bit Load Sequence:

              Byte #1                       Byte #2                       Byte #3
              Command                   MSB                             LSB
 LTC2666-16 : C3 C2 C1 C0 A3 A2 A1 A0   D15 D14 D13 D12 D11 D10 D9 D8   D7 D6 D5 D4 D3 D2 D1 D0
 LTC2666-12 : C3 C2 C1 C0 A3 A2 A1 A0   D11 D10 D9  D8  D7  D6  D5 D4   D3 D2 D1 D0 X  X  X  X

 32-Bit Load Sequence:
              Byte #1                       Byte #2                       Byte #3                 Byte #4
              Command                   MSB                             LSB
 LTC2666-16 : X  X  X  X  X  X  X  X    C3 C2 C1 C0 A3 A2 A1 A0   D15 D14 D13 D12 D11 D10 D9 D8   D7 D6 D5 D4 D3 D2 D1 D0
 LTC2666-12 : X  X  X  X  X  X  X  X    C3 C2 C1 C0 A3 A2 A1 A0   D11 D10 D9  D8  D7  D6  D5 D4   D3 D2 D1 D0 X  X  X  X

 Cx   : DAC Command Code
 Ax   : DAC Address (0 to F, corresponding to DAC 0 to DAC 15)
 Dx   : DAC Data Bits
 X    : Don't care

http://www.linear.com/product/LTC2666

http://www.linear.com/product/LTC2666#demoboards

Copyright 2018(c) Analog Devices, Inc.

All rights reserved.

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Header for LTC2666: 8-Channel SPI 16-/12-Bit +/-10V Vout SoftSpan DACs with 10ppm/C Max Reference

Definition in file LTC2666.h.

Go to the source code of this file.

Functions

int8_t LTC2666_write (uint8_t cs, uint8_t dac_command, uint8_t dac_address, uint16_t dac_code)
 Write the 16-bit dac_code to the LTC2666. More...
 
uint16_t LTC2666_voltage_to_code (float dac_voltage, float min_output, float max_output)
 Calculate a LTC2666 DAC code given the desired output voltage and DAC address (0-3) More...
 
float LTC2666_code_to_voltage (uint16_t dac_code, float min_output, float max_output)
 Calculate the LTC2666 DAC output voltage given the DAC code, offset, and LSB. More...
 

Macros

#define LTC2666_CS   QUIKEVAL_CS
 Define the SPI CS pin. More...
 
LTC2666 Command Codes

OR'd together with the DAC address to form the command byte

#define LTC2666_CMD_WRITE_N   0x00
 Write to input register n. More...
 
#define LTC2666_CMD_UPDATE_N   0x10
 Update (power up) DAC register n. More...
 
#define LTC2666_CMD_WRITE_N_UPDATE_ALL   0x20
 Write to input register n, update (power-up) all. More...
 
#define LTC2666_CMD_WRITE_N_UPDATE_N   0x30
 Write to input register n, update (power-up) More...
 
#define LTC2666_CMD_POWER_DOWN_N   0x40
 Power down n. More...
 
#define LTC2666_CMD_POWER_DOWN_ALL   0x50
 Power down chip (all DAC's, MUX and reference) More...
 
#define LTC2666_CMD_SPAN   0x60
 Write span to dac n. More...
 
#define LTC2666_CMD_CONFIG   0x70
 Configure reference / toggle. More...
 
#define LTC2666_CMD_WRITE_ALL   0x80
 Write to all input registers. More...
 
#define LTC2666_CMD_UPDATE_ALL   0x90
 Update all DACs. More...
 
#define LTC2666_CMD_WRITE_ALL_UPDATE_ALL   0xA0
 Write to all input reg, update all DACs. More...
 
#define LTC2666_CMD_MUX   0xB0
 Select MUX channel (controlled by 5 LSbs in data word) More...
 
#define LTC2666_CMD_TOGGLE_SEL   0xC0
 Select which DACs can be toggled (via toggle pin or global toggle bit) More...
 
#define LTC2666_CMD_GLOBAL_TOGGLE   0xD0
 Software toggle control via global toggle bit. More...
 
#define LTC2666_CMD_SPAN_ALL   0xE0
 Set span for all DACs. More...
 
#define LTC2666_CMD_NO_OPERATION   0xF0
 No operation. More...
 
LTC2666 Span Codes

Descriptions are valid for a 2.5V reference.

These can also be interpreted as 0 to 2*Vref, 0 to 4*Vref, etc. when an external reference other than 2.5V is used.

#define LTC2666_SPAN_0_TO_5V   0x0000
 
#define LTC2666_SPAN_0_TO_10V   0x0001
 
#define LTC2666_SPAN_PLUS_MINUS_5V   0x0002
 
#define LTC2666_SPAN_PLUS_MINUS_10V   0x0003
 
#define LTC2666_SPAN_PLUS_MINUS_2V5   0x0004
 
LTC2666 Configuration options

Used in conjunction with LTC2666_CMD_CONFIG command

#define LTC2666_REF_DISABLE   0x0001
 
#define LTC2666_THERMAL_SHUTDOWN   0x0002
 
LTC2666 MUX enable

Used in conjunction with LTC2666_CMD_MUX command

#define LTC2666_MUX_DISABLE   0x0000
 
#define LTC2666_MUX_ENABLE   0x0010
 
LTC2666 Global Toggle

Used in conjunction with LTC2666_CMD_GLOBAL_TOGGLE command, affects DACs whose Toggle Select bits have been set to 1

#define LTC2666_TOGGLE_REG_A   0x0000
 
#define LTC2666_TOGGLE_REG_B   0x0010
 

Variables

LTC2666 Minimums and Maximums for each Span

Lookup tables for minimum and maximum outputs for a given span

const float LTC2666_MIN_OUTPUT [5] = {0.0, 0.0, -5.0, -10.0, -2.5}
 
const float LTC2666_MAX_OUTPUT [5] = {5.0, 10.0, 5.0, 10.0, 2.5}
 

Function Documentation

◆ LTC2666_code_to_voltage()

float LTC2666_code_to_voltage ( uint16_t  dac_code,
float  min_output,
float  max_output 
)

Calculate the LTC2666 DAC output voltage given the DAC code, offset, and LSB.

Returns
the output voltage

Definition at line 117 of file LTC2666.cpp.

◆ LTC2666_voltage_to_code()

uint16_t LTC2666_voltage_to_code ( float  dac_voltage,
float  min_output,
float  max_output 
)

Calculate a LTC2666 DAC code given the desired output voltage and DAC address (0-3)

Returns
The 16 bit code to send to the DAC

Definition at line 103 of file LTC2666.cpp.

◆ LTC2666_write()

int8_t LTC2666_write ( uint8_t  cs,
uint8_t  dac_command,
uint8_t  dac_address,
uint16_t  dac_code 
)

Write the 16-bit dac_code to the LTC2666.

Returns
Zero if readback (SDO) data matches the value previously sent, One if mismatched (indicating data error somewhere)

Definition at line 70 of file LTC2666.cpp.

Macro Definition Documentation

◆ LTC2666_CMD_CONFIG

#define LTC2666_CMD_CONFIG   0x70

Configure reference / toggle.

Definition at line 103 of file LTC2666.h.

◆ LTC2666_CMD_GLOBAL_TOGGLE

#define LTC2666_CMD_GLOBAL_TOGGLE   0xD0

Software toggle control via global toggle bit.

Definition at line 109 of file LTC2666.h.

◆ LTC2666_CMD_MUX

#define LTC2666_CMD_MUX   0xB0

Select MUX channel (controlled by 5 LSbs in data word)

Definition at line 107 of file LTC2666.h.

◆ LTC2666_CMD_NO_OPERATION

#define LTC2666_CMD_NO_OPERATION   0xF0

No operation.

Definition at line 111 of file LTC2666.h.

◆ LTC2666_CMD_POWER_DOWN_ALL

#define LTC2666_CMD_POWER_DOWN_ALL   0x50

Power down chip (all DAC's, MUX and reference)

Definition at line 100 of file LTC2666.h.

◆ LTC2666_CMD_POWER_DOWN_N

#define LTC2666_CMD_POWER_DOWN_N   0x40

Power down n.

Definition at line 99 of file LTC2666.h.

◆ LTC2666_CMD_SPAN

#define LTC2666_CMD_SPAN   0x60

Write span to dac n.

Definition at line 102 of file LTC2666.h.

◆ LTC2666_CMD_SPAN_ALL

#define LTC2666_CMD_SPAN_ALL   0xE0

Set span for all DACs.

Definition at line 110 of file LTC2666.h.

◆ LTC2666_CMD_TOGGLE_SEL

#define LTC2666_CMD_TOGGLE_SEL   0xC0

Select which DACs can be toggled (via toggle pin or global toggle bit)

Definition at line 108 of file LTC2666.h.

◆ LTC2666_CMD_UPDATE_ALL

#define LTC2666_CMD_UPDATE_ALL   0x90

Update all DACs.

Definition at line 105 of file LTC2666.h.

◆ LTC2666_CMD_UPDATE_N

#define LTC2666_CMD_UPDATE_N   0x10

Update (power up) DAC register n.

Definition at line 96 of file LTC2666.h.

◆ LTC2666_CMD_WRITE_ALL

#define LTC2666_CMD_WRITE_ALL   0x80

Write to all input registers.

Definition at line 104 of file LTC2666.h.

◆ LTC2666_CMD_WRITE_ALL_UPDATE_ALL

#define LTC2666_CMD_WRITE_ALL_UPDATE_ALL   0xA0

Write to all input reg, update all DACs.

Definition at line 106 of file LTC2666.h.

◆ LTC2666_CMD_WRITE_N

#define LTC2666_CMD_WRITE_N   0x00

Write to input register n.

Definition at line 95 of file LTC2666.h.

◆ LTC2666_CMD_WRITE_N_UPDATE_ALL

#define LTC2666_CMD_WRITE_N_UPDATE_ALL   0x20

Write to input register n, update (power-up) all.

Definition at line 97 of file LTC2666.h.

◆ LTC2666_CMD_WRITE_N_UPDATE_N

#define LTC2666_CMD_WRITE_N_UPDATE_N   0x30

Write to input register n, update (power-up)

Definition at line 98 of file LTC2666.h.

◆ LTC2666_CS

#define LTC2666_CS   QUIKEVAL_CS

Define the SPI CS pin.

Definition at line 90 of file LTC2666.h.

◆ LTC2666_MUX_DISABLE

#define LTC2666_MUX_DISABLE   0x0000

Definition at line 143 of file LTC2666.h.

◆ LTC2666_MUX_ENABLE

#define LTC2666_MUX_ENABLE   0x0010

Definition at line 144 of file LTC2666.h.

◆ LTC2666_REF_DISABLE

#define LTC2666_REF_DISABLE   0x0001

Definition at line 136 of file LTC2666.h.

◆ LTC2666_SPAN_0_TO_10V

#define LTC2666_SPAN_0_TO_10V   0x0001

Definition at line 120 of file LTC2666.h.

◆ LTC2666_SPAN_0_TO_5V

#define LTC2666_SPAN_0_TO_5V   0x0000

Definition at line 119 of file LTC2666.h.

◆ LTC2666_SPAN_PLUS_MINUS_10V

#define LTC2666_SPAN_PLUS_MINUS_10V   0x0003

Definition at line 122 of file LTC2666.h.

◆ LTC2666_SPAN_PLUS_MINUS_2V5

#define LTC2666_SPAN_PLUS_MINUS_2V5   0x0004

Definition at line 123 of file LTC2666.h.

◆ LTC2666_SPAN_PLUS_MINUS_5V

#define LTC2666_SPAN_PLUS_MINUS_5V   0x0002

Definition at line 121 of file LTC2666.h.

◆ LTC2666_THERMAL_SHUTDOWN

#define LTC2666_THERMAL_SHUTDOWN   0x0002

Definition at line 137 of file LTC2666.h.

◆ LTC2666_TOGGLE_REG_A

#define LTC2666_TOGGLE_REG_A   0x0000

Definition at line 151 of file LTC2666.h.

◆ LTC2666_TOGGLE_REG_B

#define LTC2666_TOGGLE_REG_B   0x0010

Definition at line 152 of file LTC2666.h.

Variable Documentation

◆ LTC2666_MAX_OUTPUT

const float LTC2666_MAX_OUTPUT[5] = {5.0, 10.0, 5.0, 10.0, 2.5}

Definition at line 130 of file LTC2666.h.

◆ LTC2666_MIN_OUTPUT

const float LTC2666_MIN_OUTPUT[5] = {0.0, 0.0, -5.0, -10.0, -2.5}

Definition at line 129 of file LTC2666.h.