Rainbow Electronics MAX7360 - Manual (Page 13)

I 2 C-Interfaced Key-Switch Controller and LED
Driver/GPIOs with Integrated ESD Protection
MAX7360
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fade in automatically cancels that port’s fade and
immediately output at its newly programmed intensity.
4) Put the part into shutdown to cause all ports to fade
out. Changing an individual PWM intensity during
fade out automatically cancels that port’s fade and
immediately turns off.
Blink
Each port has its own blink control settings through
registers 0x58 to 0x5F (see Table 25 in the Register Tables
section). The blink period ranges from 0 (blink disabled)
to 4.096s. Settable blink duty cycles range from 6.25%
to 50%. All blink periods start at the same PWM cycle for
synchronized blinking between multiple ports.
GPIO Port Interrupts (INTI)
Three possible sources generate INTI: I 2 C timeout,
GPIOs configured as inputs, and the rotary switch
(registers 0x48, 0x49, and 0x4A). Read the respective
data/status registers for each type of interrupt to clear
INTI. Set register 0x46 for rotary switch-based interrupts.
Set registers 0x58 to 0x5F for individual GPI-based
interrupts. If multiple sources generate the interrupt, all
the related status registers must be read to clear INTI.
Rotary Switch
The MAX7360 can accept a 2-bit rotary switch inputs on
PORT6 and PORT7. Rotation of the switch in a clockwise
direction increments the count. Enable rotary switch
mode from the GPIO global configuration register (0x40).
Several settings for PORT6 and PORT7 occur during
rotary switch mode:
1) Each port has a 10FA pullup to V
CC
.
2) Register 0x46 sets the debounce time.
3) A debounced rising edge on PORT6 while PORT7 is
high decreases the count.
4) A debounced rising edge on PORT6 while PORT7 is
low increases the count.
For more details, see Figure 1.
Serial Interface
Figure 2 shows the 2-wire serial interface timing details.
Serial Addressing
The MAX7360 operates as a slave that sends and
receives data through an I 2 C-compatible 2-wire interface.
The interface uses a serial-data line (SDA) and a serial-
clock line (SCL) to achieve bidirectional communication
between master(s) and slave(s). A master (typically a
microcontroller) initiates all data transfers to and from the
MAX7360 and generates the SCL clock that synchronizes
the data transfer.
The MAX7360’s SDA line operates as both an input and
an open-drain output. A pullup resistor, typically 4.7kI,
Figure 2. 2-Wire Serial Interface Timing Details
SDA
SCL
t
HD, STA
t
LOW
t HIGH
t R t F
t
SU, DAT t SU, STA
t
SU, STO
t
BUF
t HD, STA
t HD, DAT
START
CONDITION
STOP
CONDITION
START
CONDITION
REPEATED
START CONDITION
t F
t F,TX
t
R
Figure 1. Rotary Switch Input Signal Timing
PORT7
PORT6
PORT7
PORT6
INCREMENT
DECREMENT
ROTARY SWITCH
DEBOUNCE