Interrupts And Overflow; Figure 16.Control Port Timing, I²C Read - Cirrus Logic CS5346 Manual

0 1 2 3 4 5
SCL
CHIP ADDRESS (WRITE)
SDA
1 0 0 1 1 AD1 AD0 0
START
Since the read operation cannot set the MAP, an aborted write operation is used as a preamble. As shown
in Figure 16, the write operation is aborted after the acknowledge for the MAP byte by sending a stop con-
dition. The following pseudocode illustrates an aborted write operation followed by a read operation.
• Send start condition.
• Send 10011xx0 (chip address & write operation).
• Receive acknowledge bit.
• Send MAP byte.
• Receive acknowledge bit.
• Send stop condition, aborting write.
• Send start condition.
• Send 10011xx1(chip address & read operation).
• Receive acknowledge bit.
• Receive byte, contents of selected register.
• Send acknowledge bit.
• Send stop condition.
5.8

Interrupts and Overflow

The CS5346 has a comprehensive interrupt capability. The INT output pin is int e nded to drive the interrupt
input pin on the host microcontroller. The INT pin may function as either an active high CMOS driver or
an active-low, open-drain driver (see "Active High/Low (Bit 0)" on page 35). When configured as active
low open-drain, the INT pin has no active pull-up transistor, allowing it to be used for wired-OR hook-ups
with multiple peripherals connected to the microcontroller interrupt input pin. In this configuration, an ex-
ternal pull-up resistor must be placed on the INT pin for proper operation.
Many conditions can cause an interrupt, as listed in the interrupt status register descriptions (see "Inter-
rupt Status - Address 0Dh" on page 35). Each source may be masked off through mask register bits. In
addition, Each source may be set to rising edge, falling edge, or level-sensitive. Combined with the option
of level-sensitive or edge-sensitive modes within the microcontroller, many different configurations are
possible, depending on the needs of the equipment designer.
The CS5346 also has a dedicated overflow output. The OVFL pin functions as active low open drain and
has no active pull-up transistor, thereby requiring an external pull-up resistor. The OVFL pin outputs an
OR of the ADCOverflow and ADCUnderflow conditions available in the Interrupt Status register; however,
these conditions do not need to be unmasked for proper operation of the OVFL pin.
DS861PP3
6 7 8 9 10 11 12 13 14 15 16
MAP BYTE
7 6 5 4 3 2 1
ACK
Figure 16. Control Port Timing, I²C Read
17 18 19 20 21 22 23 24 25
STOP
CHIP ADDRESS (READ)
0 1 0 0 1 1 AD1 AD0 1
ACK
START
26 27 28
DATA DATA +1 DATA + n
7 0 7 0 7
ACK ACK
CS5346
0
NO
ACK
STOP
25