Datasheet

Reading Device Registers

Any register data within the MAX6954 may be read by

sending a logic-high to bit D15. The sequence is:

1) Take CLK low.

2) Take CS low. This enables the internal 16-bit shift

3) Clock 16 bits of data into DIN, D15 rst to D0 last.

D15 is high, indicating a read command and bits

D14 through D8 contain the address of the register

Table 5. Serial-Data Format (16 Bits)

*Each cathode driver output (CC0-CC7) connects to two digit common cathode pins.

Table 4. Connection Scheme for Sixteen 7-Segment Digits

Table 3. Connection Scheme for Eight 14-Segment Digits

Table 2. Connection Scheme for Eight 16-Segment Digits

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

R/W ADDRESS MSB DATA LSB

DIGIT* O0 O1 O2 O3 O4 O5 O6 O7 O8 O9 O10 O11 O12 O13 O14 O15 O16 O17 O18

0, 0a CC0 — 1a — 1b 1c 1d 1dp 1e 1f 1g 2a 2b 2c 2d 2e 2f 2g 2dp

1, 1a — CC1 1a — 1b 1c 1d 1dp 1e 1f 1g 2a 2b 2c 2d 2e 2f 2g 2dp

2, 2a 1a — CC2 — 1b 1c 1d 1dp 1e 1f 1g 2a 2b 2c 2d 2e 2f 2g 2dp

3, 3a 1a — — CC3 1b 1c 1d 1dp 1e 1f 1g 2a 2b 2c 2d 2e 2f 2g 2dp

4, 4a 1a — 1b 1c CC4 — 1d 1dp 1e 1f 1g 2a 2b 2c 2d 2e 2f 2g 2dp

5, 5a 1a — 1b 1c — CC5 1d 1dp 1e 1f 1g 2a 2b 2c 2d 2e 2f 2g 2dp

6, 6a 1a — 1b 1c 1d 1dp CC6 — 1e 1f 1g 2a 2b 2c 2d 2e 2f 2g 2dp

7, 7a 1a — 1b 1c 1d 1dp — CC7 1e 1f 1g 2a 2b 2c 2d 2e 2f 2g 2dp

DIGIT O0 O1 O2 O3 O4 O5 O6 O7 O8 O9 O10 O11 O12 O13 O14 O15 O16 O17 O18

0 CCO — a — b c d — e f g1 g2 h i j k l m dp

1 — CC1 a — b c d — e f g1 g2 h i j k l m dp

2 a — CC2 — b c d — e f g1 g2 h i j k l m dp

3 a — — CC3 b c d — e f g1 g2 h i j k l m dp

4 a — b c CC4 — d — e f g1 g2 h i j k l m dp

5 a — b c — CC5 d — e f g1 g2 h i j k l m dp

6 a — b c d — CC6 — e f g1 g2 h i j k l m dp

7 a — b c d — — CC7 e f g1 g2 h i j k l m dp

DIGIT O0 O1 O2 O3 O4 O5 O6 O7 O8 O9 O10 O11 O12 O13 O14 O15 O16 O17 O18

0 CCO — a1 a2 b c d1 d2 e f g1 g2 h i j k l m dp

1 — CC1 a1 a2 b c d1 d2 e f g1 g2 h i j k l m dp

2 a1 a2 CC2 — b c d1 d2 e f g1 g2 h i j k l m dp

3 a1 a2 — CC3 b c d1 d2 e f g1 g2 h i j k l m dp

4 a1 a2 b c CC4 — d1 d2 e f g1 g2 h i j k l m dp

5 a1 a2 b c — CC5 d1 d2 e f g1 g2 h i j k l m dp

6 a1 a2 b c d1 d2 CC6 — e f g1 g2 h i j k l m dp

7 a1 a2 b c d1 d2 — CC7 e f g1 g2 h i j k l m dp

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MAX6954 4-Wire Interfaced, 2.7V to 5.5V LED Display

Driver with I/O Expander and Key Scan