EVAL-AD5429EB View Datasheet(PDF) - Analog Devices
Part Name
Description
MFG CO.
EVAL-AD5429EB
Analog Devices
'EVAL-AD5429EB' PDF : 32 Pages View PDF
MC68HC11 to AD5429/AD5439/AD5449 Interface
Figure 50 is an example of a serial interface between the DAC
and the MC68HC11 microcontroller. 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. The SCK of the 68HC11 drives the SCLK of the DAC
interface; the MOSI output drives the serial data line (DIN) of
the AD5429/AD5439/AD5449.
The SYNC signal is derived from a port line (PC7). When data
is being transmitted to the AD5429/AD5439/AD5449, 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 8 falling clock
edges occurring in the transmit cycle. Data is transmitted MSB
first. To load data to the DAC, PC7 is left low after the first eight
bits are transferred, and a second serial write operation is
performed to the DAC. PC7 is taken high at the end of this
procedure.
MC68HC11*
PC7
SCK
MOSI
AD5429/AD5439/
AD5449*
SYNC
SCLK
SDIN
*ADDITIONAL PINS OMITTED FOR CLARITY
Figure 50. MCH68HC11/68L11 to AD5429/AD5439/AD5449 Interface
If the user wants to verify the data previously written to the
input shift register, the SDO line can be connected to MISO of
the MC68HC11, and, with SYNC low, the shift register clocks
data out on the rising edges of SCLK.
AD5429/AD5439/AD5449
MICROWIRE to AD5429/AD5439/AD5449 Interface
Figure 51 shows an interface between the DAC and any
MICROWIRE compatible device. Serial data is shifted out on
the falling edge of the serial clock, SK, and is clocked into the
DAC input shift register on the rising edge of SK, which
corresponds to the falling edge of the DAC’s SCLK.
MICROWIRE*
SK
SO
CS
AD5429/AD5439/
AD5449*
SCLK
SDIN
SYNC
*ADDITIONAL PINS OMITTED FOR CLARITY
Figure 51. MICROWIRE to AD5429/AD5439/AD5449 Interface
PIC16C6x/7x to AD5429/AD5439/AD5449
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 the PIC16/17 Microcontroller User Manual.
In this example, the I/O port RA1 is used to provide a SYNC
signal and enable the serial port of the DAC. This micro-
controller transfers only eight bits of data during each serial
transfer operation; therefore, two consecutive write operations
are required. Figure 52 shows the connection diagram.
PIC16C6x/7x*
SCK/RC3
SDI/RC4
RA1
AD5429/AD5439/
AD5449*
SCLK
SDIN
SYNC
*ADDITIONAL PINS OMITTED FOR CLARITY
Figure 52. PIC16C6x/7x to AD5429/AD5439/AD5449 Interface
Rev. 0 | Page 23 of 32
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