AD5516-1 Analog Devices, AD5516-1 Datasheet - Page 12

• Manufacturer Part Number: AD5516-1
• Description: 16-Channel/ 12-Bit Voltage-Output DAC with 14-Bit Increment Mode
• Manufacturer: Analog Devices

AD5516
A data transfer is initiated by writing a word to the TX register
after the SPORT has been enabled. In write sequences data is
clocked out on each rising edge of the DSP’s serial clock and
clocked into the AD5516 on the falling edge of its SCLK. The
SPORT transmit control register should be set up as follows:
DTYPE = 00, Right Justify Data
ICLK
TFSR
INTF
LTFS
LAFS
SENDN = 0, Data Transmitted MSB First
SLEN
Figure 6 shows the connection diagram.
AD5516 to MC68HC11
The serial peripheral interface (SPI) on the MC68HC11 is
configured for master mode (MSTR = 1), clock polarity bit
(CPOL) = 0, and the clock phase bit (CPHA) = 1. The SPI is
configured by writing to the SPI control register (SPCR)—see
the 68HC11 User Manual. SCK of the 68HC11 drives the SCLK
of the AD5516, the MOSI output drives the serial data line
(D
line (PC7). When data is being transmitted to the AD5516, the
SYNC line is taken low (PC7). Data appearing on the MOSI
output is valid on the falling edge of SCK. Serial data from the
68HC11 is transmitted in 8-bit bytes with only eight falling
clock edges occurring in the transmit cycle. Data is transmitted
MSB first. In order to transmit 18 data bits, it is important to
left justify the data in the SPDR register. PC7 must be pulled
low to start a transfer and taken high and low again before any
further read/write cycles can take place. A connection diagram is
shown in Figure 7.
IN
) of the AD5516. The SYNC signal is derived from a port
ADDITIONAL PINS OMITTED FOR CLARITY
ADDITIONAL PINS OMITTED FOR CLARITY
= 1, Internal Serial Clock
= 1, Frame Every Word
= 1, Internal Frame Sync
= 1, Active Low Frame Sync Signal
= 0, Early Frame Sync
= 10011, 18-Bit Data Words (SLEN = Serial Word)
AD5516
AD5516
SYNC
SCLK
SYNC
SCLK
D
D
IN
IN
TFS
DT
SCLK
PC7
SCK
MOSI
ADSP-2106x
MC68HC11
AD5516 to PIC16C6x/7x
The PIC16C6x/7x synchronous serial port (SSP) is configured
as an SPI master with the clock polarity bit (CKP) = 0. This is
done by writing to the synchronous serial port control register
(SSPCON). See user PIC16/17 Microcontroller User Manual.
In this example, I/O port RA1 is being used to provide a SYNC
signal and enable the serial port of the AD5516. This microcon-
troller transfers only eight bits of data during each serial transfer
operation; therefore, three consecutive write operations are
required. Figure 8 shows the connection diagram.
AD5516 to 8051
A serial interface between the AD5516 and the 80C51/80L51
microcontroller is shown in Figure 9. The AD5516 requires a
clock synchronized to the serial data. The 8051 serial interface
must therefore be operated in Mode 0. TxD of the microcon-
troller drives the SCLK of the AD5516, while RxD drives the
serial data line. P3.3 is a bit programmable pin on the serial port
that is used to drive SYNC. The 80C51/80L51 provides the
LSB first, while the AD5516 expects MSB of the 18-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 AD5516 clocks data into the
input shift register on the rising edge of the serial clock. The
80C51/80L51 transmits its data in 8-bit bytes with only eight
falling clock edges occurring in the transmit cycle. As the DAC
requires an 18-bit word, P3.3 must be left low after the first eight
bits are transferred, and brought high after the complete 18 bits
have been transferred. DOUT may be tied to RxD for data verifi-
cation purposes when the device is in daisy-chain mode.
ADDITIONAL PINS OMITTED FOR CLARITY
ADDITIONAL PINS OMITTED FOR CLARITY
AD5516
AD5516
SCLK
SYNC
SCLK
SYNC
D
D
IN
IN
SCK/RC3
SDI/RC4
RA1
TxD
RxD
P1.1
PIC16C6x/7x
8051