MAX16816 Datasheet, PDF (26/33 Pages) Maxim Integrated Products – Programmable Switch-Mode LED Driver with Analog-Controlled PWM Dimming

Programmable Switch-Mode LED Driver
with Analog-Controlled PWM Dimming
Programming Sequences
The µC (master) starts the communication with the
MAX16816 by pulling UVEN high. The MAX16816 then
does the handshaking with the µC by pulling FAULT low.
Once the µC receives the handshaking signal, it begins
the initialization sequences to reset the 1-Wire interface.
The sequence consists of a reset pulse from the µC fol-
lowed by a presence pulse from the MAX16816. At this
point the µC must send PASS_CODE_ONE and
PASS_CODE_TWO. These pass codes must be received
by the MAX16816 within the 8ms programming slot to
allow the MAX16816 to enter the EE programming mode.
1-Wire Signaling
The MAX16816 requires strict protocols to ensure data
integrity. The protocol consists of four types of signal-
ing on one line: reset sequence with Reset Pulse and
Presence Pulse, Write-Zero, Write-One, and Read-Data.
Except for the Presence Pulse, the bus master initiates
all falling edges.
Externally pull FAULT below V_IL to indicate a logic-input
low. Release the pulldown device to indicate a logic-
input high. The MAX16816 will pull FAULT low below
V_OL to indicate a logic-output low. FAULT is pulled high
with an internal 10kΩ resistor above V_OH to indicate a
logic-output high.
Initialization Procedure
(Reset and Presence Pulses)
All 1-Wire communication with the MAX16816 begins
with an initialization sequence that consists of a Reset
Pulse from the master followed by a Presence Pulse
from the MAX16816 (Figure 6). When the MAX16816
sends the Presence Pulse in response to the Reset
Pulse, it is indicating to the master that it is ready to
receive and transmit data.
During the initialization sequence, the bus master trans-
mits the reset pulse by pulling the 1-Wire bus low for a
minimum of 480µs. The bus master then releases the
bus and goes into receive mode. When the bus is
released, the pullup resistor pulls the 1-Wire bus high.
When the MAX16816 detects this rising edge, it waits
15µs to 60µs and then transmits a Presence Pulse by
pulling the 1-Wire bus low for 60µs to 240µs.
Read and Write Time Slots
The bus master writes data to the MAX16816 during
write time slots and reads data from the MAX16816
during read time slots. One bit of data is transmitted
over the 1-Wire bus per time slot.
MASTER Tx "RESET PULSE"
MASTER Rx "PRESENCE PULSE"
t_MSP
V_OH
V_OL OR V_IL
0V
t_RSTL
RESISTOR
Figure 6. 1-Wire Initialization Timing
MASTER
MAX16816
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