Datasheet MAX7219, MAX7221 (Analog Devices) - 7
| Manufacturer | Analog Devices |
| Description | Serially Interfaced, 8-Digit, LED Display Drivers |
| Pages / Page | 15 / 7 — Table 2. Register Address Map. Initial Power-Up. ADDRESS. REGISTER. HEX. … |
| File Format / Size | PDF / 1.4 Mb |
| Document Language | English |
Table 2. Register Address Map. Initial Power-Up. ADDRESS. REGISTER. HEX. D15–. CODE. D12. D11. D10. Decode-Mode Register
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Text Version of Document
MAX7219/MAX7221 Serially Interfaced, 8-Digit LED Display Drivers
Table 2. Register Address Map Initial Power-Up
On initial power-up, all control registers are reset, the
ADDRESS
display is blanked, and the MAX7219/MAX7221 enter
REGISTER HEX D15–
shutdown mode. Program the display driver prior to
CODE D12 D11 D10 D9 D8
display use. Otherwise, it will initially be set to scan one digit, it will not decode data in the data registers, and the No-Op X 0 0 0 0 0xX0 intensity register will be set to its minimum value. Digit 0 X 0 0 0 1 0xX1
Decode-Mode Register
Digit 1 X 0 0 1 0 0xX2 The decode-mode register sets BCD code B (0-9, E, H, L, Digit 2 X 0 0 1 1 0xX3 P, and -) or no-decode operation for each digit. Each bit in Digit 3 X 0 1 0 0 0xX4 the register corresponds to one digit. A logic high selects code B decoding while logic low bypasses the decoder. Digit 4 X 0 1 0 1 0xX5 Examples of the decode mode control-register format are Digit 5 X 0 1 1 0 0xX6 shown in Table 4. Digit 6 X 0 1 1 1 0xX7 When the code B decode mode is used, the decoder looks only at the lower nibble of the data in the digit registers Digit 7 X 1 0 0 0 0xX8 (D3–D0), disregarding bits D4–D6. D7, which sets the Decode decimal point (SEG DP), is independent of the decoder Mode X 1 0 0 1 0xX9 and is positive logic (D7 = 1 turns the decimal point on). Intensity X 1 0 1 0 0xXA Table 5 lists the code B font. Scan Limit X 1 0 1 1 0xXB When no-decode is selected, data bits D7–D0 correspond to the segment lines of the MAX7219/MAX7221. Table 6 Shutdown X 1 1 0 0 0xXC shows the one-to-one pairing of each data bit to the appropriate Display segment line. Test X 1 1 1 1 0xXF
Table 3. Shutdown Register Format (Address (Hex) = 0xXC) REGISTER DATA MODE ADDRESS CODE (HEX) D7 D6 D5 D4 D3 D2 D1 D0
Shutdown Mode 0xXC X X X X X X X X Normal Operation 0xXC X X X X X X X 1
Table 4. Decode-Mode Register Examples (Address (Hex) = 0xX9) REGISTER DATA DECODE MODE HEX CODE D7 D6 D5 D4 D3 D2 D1 D0
No decode for digits 7–0 0 0 0 0 0 0 0 0 0x00 Code B decode for digit 0 No decode for digits 7–1 0 0 0 0 0 0 0 1 0x01 Code B decode for digits 3–0 No decode for digits 7–4 0 0 0 0 1 1 1 1 0x0F Code B decode for digits 7–0 1 1 1 1 1 1 1 1 0xFF www.maximintegrated.com Maxim Integrated │ 7
Table 2. Register Address Map Initial Power-Up
On initial power-up, all control registers are reset, the
ADDRESS
display is blanked, and the MAX7219/MAX7221 enter
REGISTER HEX D15–
shutdown mode. Program the display driver prior to
CODE D12 D11 D10 D9 D8
display use. Otherwise, it will initially be set to scan one digit, it will not decode data in the data registers, and the No-Op X 0 0 0 0 0xX0 intensity register will be set to its minimum value. Digit 0 X 0 0 0 1 0xX1
Decode-Mode Register
Digit 1 X 0 0 1 0 0xX2 The decode-mode register sets BCD code B (0-9, E, H, L, Digit 2 X 0 0 1 1 0xX3 P, and -) or no-decode operation for each digit. Each bit in Digit 3 X 0 1 0 0 0xX4 the register corresponds to one digit. A logic high selects code B decoding while logic low bypasses the decoder. Digit 4 X 0 1 0 1 0xX5 Examples of the decode mode control-register format are Digit 5 X 0 1 1 0 0xX6 shown in Table 4. Digit 6 X 0 1 1 1 0xX7 When the code B decode mode is used, the decoder looks only at the lower nibble of the data in the digit registers Digit 7 X 1 0 0 0 0xX8 (D3–D0), disregarding bits D4–D6. D7, which sets the Decode decimal point (SEG DP), is independent of the decoder Mode X 1 0 0 1 0xX9 and is positive logic (D7 = 1 turns the decimal point on). Intensity X 1 0 1 0 0xXA Table 5 lists the code B font. Scan Limit X 1 0 1 1 0xXB When no-decode is selected, data bits D7–D0 correspond to the segment lines of the MAX7219/MAX7221. Table 6 Shutdown X 1 1 0 0 0xXC shows the one-to-one pairing of each data bit to the appropriate Display segment line. Test X 1 1 1 1 0xXF
Table 3. Shutdown Register Format (Address (Hex) = 0xXC) REGISTER DATA MODE ADDRESS CODE (HEX) D7 D6 D5 D4 D3 D2 D1 D0
Shutdown Mode 0xXC X X X X X X X X Normal Operation 0xXC X X X X X X X 1
Table 4. Decode-Mode Register Examples (Address (Hex) = 0xX9) REGISTER DATA DECODE MODE HEX CODE D7 D6 D5 D4 D3 D2 D1 D0
No decode for digits 7–0 0 0 0 0 0 0 0 0 0x00 Code B decode for digit 0 No decode for digits 7–1 0 0 0 0 0 0 0 1 0x01 Code B decode for digits 3–0 No decode for digits 7–4 0 0 0 0 1 1 1 1 0x0F Code B decode for digits 7–0 1 1 1 1 1 1 1 1 0xFF www.maximintegrated.com Maxim Integrated │ 7