CS4349
6.3.2
SPI Read
To read from the device, follow the procedure below while adhering to the values specified in ”Switching
Characteristics - Control Port - SPI Format” on page 15.
1. Bring CS low.
2. The address byte on the CDIN pin must then be 10011111 (R/W = 1).
3. CDOUT pin will then output the data from the register pointed to by the MAP, which is set during the
SPI write operation.
4. If the INCR bit (see Section 6.1) is set to 1, keep CS low and continue providing clocks on CCLK to
read from multiple consecutive registers. Bring CS high when reading is complete.
5. If the INCR bit is set to 0 and further SPI reads from other registers are desired, it is necessary to bring
CS high, and follow the procedure detailed from step 1. If no further reads from other registers are
desired, bring CS high.
CS
CCLK
C H IP
C H IP
M A P
DATA
A D D R E S S
ADDRESS
CDIN
LSB
1001111
1001111
MSB
b y te 1
R/W
R/W
b y te n
High Impedance
CDOUT
LSB
LSB
MSB
MSB
MAP = Memory Address Pointer, 8 bits, MSB first
Figure 19. Control Port Timing, SPI Mode
6.4
Memory Address Pointer (MAP)
7
6
Reserved
0
5
Reserved
0
4
Reserved
0
3
MAP3
0
2
1
MAP1
0
0
MAP0
0
INCR
0
MAP2
0
6.4.1
INCR (Auto Map Increment Enable)
Default = ‘0’
0 - Disabled
1 - Enabled
6.4.2
MAP (Memory Address Pointer)
Default = ‘0000’
DS782F1
27
CIRRUS [ CIRRUS LOGIC ]
