Datasheet

Low-Voltage Operation
The MAX6957 operates down to 2V supply voltage
(although the sourcing and sinking currents are not
guaranteed), providing that the MAX6957 is powered
up initially to at least 2.5V to trigger the device’s internal
reset, and also that the serial interface is constrained to
10Mbps.
Table 14. Display Test Register
X = Don’t care bit.
Table 13. Transition Detection Mask Register
X = Don’t care bit.
Table 12. Odd Individual Segment Current Format
MODE
ADDRESS CODE
(HEX)
REGISTER DATA
D7 D6 D5 D4 D3 D2 D1 D0
Normal Operation 0x07 X X X X X X X 0
Display Test Mode 0x07 X X X X X X X 1
FUNCTION
REGISTER
ADDRESS
(HEX)
READ/
WRITE
REGISTER DATA
D7 D6 D5 D4 D3 D2 D1 D0
Mask
Register
0x06
Read 0
Port
30
mask
Port
29
mask
Port
28
mask
Port
27
mask
Port
26
mask
Port
25
mask
Port
24
mask
Write Unchanged
LED DRIVE
FRACTION
SEGMENT CONSTANT
CURRENT WITH
R
ISET
= 39kΩ (mA)
ADDRESS CODE
(HEX)
D7 D6 D5 D4 D3 D2 D1 D0 HEX CODE
1/16 1.5 0x12 to 0x1F 0 0 0 0 0x0X
2/16 3 0x12 to 0x1F 0 0 0 1 0x1X
3/16 4.5 0x12 to 0x1F 0 0 1 0 0x2X
4/16 6 0x12 to 0x1F 0 0 1 1 0x3X
5/16 7.5 0x12 to 0x1F 0 1 0 0 0x4X
6/16 9 0x12 to 0x1F 0 1 0 1 0x5X
7/16 10.5 0x12 to 0x1F 0 1 1 0 0x6X
8/16 12 0x12 to 0x1F 0 1 1 1 See Table 11. 0x7X
9/16 13.5 0x12 to 0x1F 1 0 0 0 0x8X
10/16 15 0x12 to 0x1F 1 0 0 1 0x9X
11/16 16.5 0x12 to 0x1F 1 0 1 0 0xAX
12/16 18 0x12 to 0x1F 1 0 1 1 0xBX
13/16 19.5 0x12 to 0x1F 1 1 0 0 0xCX
14/16 21 0x12 to 0x1F 1 1 0 1 0xDX
15/16 22.5 0x12 to 0x1F 1 1 1 0 0xEX
16/16 24 0x12 to 0x1F 1 1 1 1 0xFX
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Maxim Integrated │ 19
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port LED Display Driver and I/O Expander