Rainbow Electronics MAX5970 - Manual (Page 35)

0V to 16V, Dual Hot-Swap Controller with 10-Bit
Current and Voltage Monitor and 4 LED Drivers
MAX5970
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Table 51. LED_Flash/GPIO Enable Register
Table 52. LED Phase/Weak Pullup Enable Register
IFAULTSx indicates the overcurrent status from slow
comparator. IFAULTFx indicates overcurrent status from
fast comparator. The status of FAULT_ reflects the NOR
operation of IFAULTSx and IFAULTFx.
These fault register bits latch upon fault condition and
are reset by restarting the affected channel as described
in the Autoretry or Latched-Off Fault Management sec-
tion.
FAULT_ Outputs
When an overcurrent event (fast-trip or slow-trip)
causes the MAX5970 to shut down the affected
channel(s), a corresponding open-drain FAULT_ out-
put is asserted low. Note that the FAULT_ outputs are
not asserted for shutdowns caused by critical under-
voltage or overvoltage.
The FAULT_ output is cleared when the channel is dis-
abled by pulling ON_ low or by clearing the bits in the
chxen register.
ALERT Output
ALERT is an open-drain output that is asserted low any
time that a fault or other condition requiring attention has
occurred. The state of the ALERT output is also indi-
cated by status3[4].
ALERT is the NOR of registers 0x31, 0x35, 0x36 and
0x37, so when the ALERT output goes low, the system
microcontroller should query these registers through
the I
2 C interface to determine the cause of the ALERT
assertion.
LED Set Registers
The MAX5970 has four open-drain LED drivers/user-
programmable GPIOs. When programmed as LED driv-
ers, each driver can sink up to 25mA of current. Table
51 shows the register that enables the drivers as either
LED drivers or GPIOs.
When any of the LED_Set bit in the register is set to 1, the
corresponding open-drain LED driver is turned OFF. The
LED_Flash bits enable each corresponding LED driver
to flash on and off at 1Hz frequency regardless of the
condition of the corresponding LED_Set bit.
Bits 7-4 in Table 52 show how to set the LED drivers to
be either in phase or out of phase with the internal 1Hz
clock. Bits 3-0 show how to enable the 4FA pullup cur-
rent to disable a corresponding LED driver.
Description: LED_Flash/GPIO Enable register
Register Title: LED_flash
Register Address: 0x43
R/W R/W R/W R/W R/W R/W R/W R/W
RESET
VALUE
LED4 Flash LED3 Flash LED2 Flash LED1 Flash LED4 Set LED3 Set LED2 Set LED1 Set 0x0F
bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
Description: LED Phase/Weak Pullup Enable register
Register Title: LED_ph_pu
Register Address: 0x44
R/W R/W R/W R/W R/W R/W R/W R/W
RESET
VALUE
LED4
Phase
LED3 Phase LED2 Phase LED1 Phase
LED4 Weak
PU
LED3 Weak
PU
LED2
Weak PU
LED1
Weak PU
0x00
bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0