STLED325QTR STMicroelectronics, STLED325QTR Datasheet - Page 50

• Manufacturer Part Number: STLED325QTR
• Description: LED Lighting Drivers I2C interfaced LED controller/driver
• Manufacturer: STMicroelectronics

Specifications of STLED325QTR

• Product Category: LED Lighting Drivers
• Rohs: yes
• Input Voltage: 5 V
• Maximum Supply Current: 2 mA
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-32
• Minimum Operating Temperature: - 40 C
• Power Dissipation: 1200 mW

Commands
7.4
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Figure 18. Interrupt bit mapping in Byte 2
In the normal mode of operation, when any FP or RC key is pressed or when
alarm/watchdog is triggered, the STLED325 sets the flags in the above interrupt flag register
and asserts the IRQ_N pin. The data which caused the interrupt to assert remains in the
buffer until it is changed by another key-press. It is up to the micro processor to issue the
read interrupt command to ascertain what caused the interrupt. If the micro processor does
not issue the interrupt within a specific time, the old data is lost and only the latest data is
reflected in the Interrupt Flag register.
In the standby mode of operation, only the hot-key will cause the interrupt flag to be set and
the IRQ_N pin will be asserted. The micro processor should then read the interrupt to know
what caused the wake-up operation before proceeding with the normal data communication
or asserting STBY again if there is no action to be performed. Upon the first read of the hot-
key data, the data in the buffer is cleared.
When the b4 of the above interrupt flag is set, then the µP should read the address 0x0F
from the RTC register space to determine if the alarm was triggered. Only after determining
this, the interrupt flag is cleared and the IRQ_N pin de-asserted.
The IRQ_N pin will only be de-asserted once the interrupt flags have been read. The chip
will continue to send the interrupt periodically (approximately every 40us) to the main Host
chip if the oscillator is down signifying to the Host chip that the frequency is out of spec.
Address setting command
This command sets an address of the display memory or the address of the RTC register
map.
The address range from 00h-0Fh represents the RTC register map. For writing data to RTC
registers, initially the address command is sent followed by the RTC data.
10h-14h represents the 7-segment and discrete LED display correspondence. On power
application, the address is set to 10h. In the auto-increment mode, when the address
reached 0x14, the next ad-dress will be 0x10.
Byte 2:
MSB
MSB
1
b7-b4 = Normal operation
1
x
Doc ID 17576 Rev 1
b4
b3
b3-b0=Wake up operation
b2
b1
STLED325
LSB
LSB
b0