Datasheet

AD5501 Data Sheet
Rev. C | Page 16 of 20
Table 10. Control Register Functions Bit Map
DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
1
R/
W
1 1 1 0 0 0 0 0 C6 C5 C4 C3 C2 C1 C0
1
Read only bit. This bit should be 0 when writing to the control register
Table 11. Control Register Function Bit Descriptions
Bit No. Bit Name Description
DB0 C0 C0 = 0: the device is not in thermal shutdown mode.
C0 = 1: the thermal shutdown mode is activated.
DB1 C1 C1 = 0: reserved. This bit should be 0 when writing to the control register.
DB2 C2 C2 = 0: DAC channel power-down (default).
C2 = 1: DAC channel power-up.
DB[3:5] C3 to C5 C3 to C5 = 0: reserved. These bits should be 0 when writing to the control register.
DB6 C6 C6 = 0: output connected to AGND through a 20 kΩ resistor.
C6 = 1: output is three-stated (default).
07994-120
WRITE N WRITE N + 1
WRITE TO
CONTROL REGISTER
NOP
WRITE TO
CONTROL REGISTER
WRITE TO
DAC REGISTER
WRITE N + 2
WRITE TO
CONTROL REGISTER
WRITE TO
CONTROL REGISTER
NOP
WRITE TO
CONTROL REGISTER
WRITE TO
CONTROL REGISTER
WRITE TO
DAC REGISTER
Figure 17. Control Register Write Sequences
INTERFACING EXAMPLES
The SPI interface of the AD5501 is designed to allow it to be easily
connected to industry-standard DSPs and microcontrollers.
Figure 18 shows how the AD5501 can be connected to the Analog
Devices, Inc., Blackfin® DSP. The Blackfin has an integrated SPI
port that can be connected directly to the SPI pins of the AD5501.
Programmable input/output pins are also available and can be
used to read or set the state of the digital input or output pins
associated with the interface.
SPISELx
ADSP-BF531
AD5501
SCK
MOSI
MISO
PF10
PF8
PF9
PF7
SYNC
SCLK
SDI
SDO
R_SEL
CLR
LDAC
ALARM
07992-017
Figure 18. Interfacing to a Blackfin DSP
The Analog Devices ADSP-21065L is a floating point DSP with
two serial ports (SPORTs). Figure 19 shows how one SPORT
can be used to control the AD5501. In this example, the transmit
frame synchronization (TFS) pin is connected to the receive frame
synchronization (RFS) pin. The transmit and receive clocks (TCLK
and RCLK) are also connected together. The user can write to the
AD5501 by writing to the transmit register. When a read operation
is performed, the data is clocked out of the AD5501 on the last
12 SCLKs. The DSP receive interrupt can be used to indicate when
the read operation is complete.
SYNC
SCLK
SDI
SDO
R_SEL
CLR
LDAC
ALARM
AD5501
ADSP-21065L
TFSx
RFSx
TCLKx
RCLKx
DTxA
DRxA
FLAG
0
FLAG
1
FLAG
2
FLAG
3
07992-018
Figure 19. Interfacing to an ADSP-21065L DSP