AD5512AACPZ AD [Analog Devices], AD5512AACPZ Datasheet - Page 16

• Manufacturer Part Number: AD5512AACPZ
• Description: 2.7 V to 5.5 V, Serial-Input, Voltage-Output, 16-/12-Bit nanoDACs in LFCSP
• Manufacturer: AD [Analog Devices]

AD5541A/AD5542A/AD5512A
MICROPROCESSOR INTERFACING
Microprocessor interfacing to the AD5541/AD5542 is via a
serial bus that uses standard protocol that is compatible with
DSP processors and microcontrollers. The communications
channel requires a 3- or 4-wire interface consisting of a clock
signal, a data signal and a synchronization signal. The
AD5541/AD5542 require a 16-bit data-word with data valid on
the rising edge of SCLK. The DAC update can be done
automatically when all the data is clocked in or it can be done
under control of the LDAC (AD5542 only).
AD5541/AD5542 TO ADSP-2101/ADSP-2103
INTERFACE
Figure 33 shows a serial interface between the AD5541/AD5542
and the ADSP-2101/ADSP-2103. The ADSP-2101/ADSP-2103
should be set to operate in the SPORT transmit alternate framing
mode. The ADSP-2101/ADSP-2103 are programmed through
the SPORT control register and should be configured as follows:
internal clock operation, active low framing, 16-bit word length.
Transmission is initiated by writing a word to the Tx register
after the SPORT has been enabled. As the data is clocked out
on each rising edge of the serial clock, an inverter is required
between the DSP and the DAC, because the AD5541/AD5542
clock data in on the falling edge of the SCLK.
AD5541/AD5542 TO 68HC11/68L11 INTERFACE
Figure 34 shows a serial interface between the AD5541/AD5542
and the 68HC11/68L11 microcontroller. SCK of the 68HC11/
68L11 drives the SCLK of the DAC, and the MOSI output drives
the serial data line serial DIN. The CS signal is driven from one
of the port lines. The 68HC11/68L11 is configured for master
mode: MSTR = 1, CPOL = 0, and CPHA = 0. Data appearing
on the MOSI output is valid on the rising edge of SCK.
Figure 33. AD5541/AD5542 to ADSP-2101/ADSP-2103 Interface
*ADDITIONAL PINS OMITTED FOR CLARITY.
**AD5542 ONLY.
*ADDITIONAL PINS OMITTED FOR CLARITY.
**AD5542 ONLY.
Figure 34. AD5541/AD5542 to 68HC11/68L11 Interface
ADSP-2101/
ADSP-2103*
68HC11/
68L11*
SCLK
MOSI
SCK
PC6
PC7
TFS
FO
DT
LDAC**
CS
DIN
SCLK
LDAC**
CS
DIN
SCLK
AD5542*
AD5542*
AD5541/
AD5541/
Rev. PrA | Page 16 of 24
AD5541/AD5542 TO MICROWIRE INTERFACE
Figure 35 shows an interface between the AD5541/AD5542
and any MICROWIRE-compatible device. Serial data is shifted
out on the falling edge of the serial clock and into the AD5541/
AD5542 on the rising edge of the serial clock. No glue logic is
required because the DAC clocks data into the input shift
register on the rising edge.
AD5541/AD5542 TO 80C51/80L51 INTERFACE
A serial interface between the AD5541/AD5542 and the 80C51/
80L51 microcontroller is shown in Figure 36. TxD of the micro-
controller drives the SCLK of the AD5541/AD5542, and RxD
drives the serial data line of the DAC. P3.3 is a bit programmable
pin on the serial port that is used to drive CS .
The 80C51/80L51 provide the LSB first, whereas the AD5541/
AD5542 expects the MSB of the 16-bit word first. Care should
be taken to ensure the transmit routine takes this into account.
When data is to be transmitted to the DAC, P3.3 is taken low.
Data on RxD is valid on the falling edge of TxD, so the clock
must be inverted as the DAC clocks data into the input shift
register on the rising edge of the serial clock. The 80C51/80L51
transmit data in 8-bit bytes with only eight falling clock edges
occurring in the transmit cycle. As the DAC requires a 16-bit
word, P3.3 must be left low after the first eight bits are transferred,
and brought high after the second byte is transferred. LDAC on
the AD5542 can also be controlled by the 80C51/ 80L51 serial
port output by using another bit programmable pin, P3.4.
*ADDITIONAL PINS OMITTED FOR CLARITY.
MICROWIRE*
*ADDITIONAL PINS OMITTED FOR CLARITY.
**AD5542 ONLY.
Figure 36. AD5541/AD5542 to 80C51/80L51 Interface
Figure 35. AD5541/AD5542 to MICROWIRE Interface
80C51/
80L51*
Preliminary Technical Data
SCLK
P3.4
P3.3
RxD
TxD
CS
SO
LDAC**
CS
DIN
SCLK
CS
DIN
SCLK
AD5541/
AD5542*
AD5541/
AD5542*