MAX7219C/D Maxim, MAX7219C/D Datasheet - Page 7

• Manufacturer Part Number: MAX7219C/D
• Description: Serially Interfaced / 8-Digit LED Display Drivers
• Manufacturer: Maxim

Table 2. Register Address Map
Table 3. Shutdown Register Format (Address (Hex) = XC)
Table 4. Decode-Mode Register Examples (Address (Hex) = X9)
No-Op
Digit 0
Digit 1
Digit 2
Digit 3
Digit 4
Digit 5
Digit 6
Digit 7
Decode
Mode
Intensity
Scan Limit
Shutdown
Display
Test
Shutdown
Mode
Normal
Operation
No decode for digits 7–0
Code B decode for digit 0
No decode for digits 7–1
Code B decode for digits 3–0
No decode for digits 7–4
Code B decode for digits 7–0
REGISTER
Serially Interfaced, 8-Digit LED Display Drivers
MODE
DECODE MODE
D15–
D12
_______________________________________________________________________________________
X
X
X
X
X
X
X
X
X
X
X
X
X
X
ADDRESS CODE
D11
(HEX)
0
0
0
0
0
0
0
0
1
1
1
1
1
1
XC
XC
ADDRESS
D10
0
0
0
0
1
1
1
1
0
0
0
0
1
1
D7
0
0
0
1
D9
0
0
1
1
0
0
1
1
0
0
1
1
0
1
D7
X
X
D8
0
1
0
1
0
1
0
1
0
1
0
1
0
1
D6
0
0
0
1
CODE
HEX
D6
XC
XA
XB
X0
X1
X2
X3
X4
X5
X6
X7
X8
X9
XF
X
X
D5
0
0
0
1
D5
X
X
On initial power-up, all control registers are reset, the
display is blanked, and the MAX7219/MAX7221 enter
shutdown mode. Program the display driver prior to
display use. Otherwise, it will initially be set to scan one
digit, it will not decode data in the data registers, and
the intensity register will be set to its minimum value.
The decode-mode register sets BCD code B (0-9, E, H,
L, P, and -) or no-decode operation for each digit. Each
bit in the register corresponds to one digit. A logic high
selects code B decoding while logic low bypasses the
decoder. Examples of the decode mode control-regis-
ter format are shown in Table 4.
When the code B decode mode is used, the decoder
looks only at the lower nibble of the data in the digit
registers (D3–D0), disregarding bits D4–D6. D7, which
sets the decimal point (SEG DP), is independent of the
decoder and is positive logic (D7 = 1 turns the decimal
point on). Table 5 lists the code B font.
When no-decode is selected, data bits D7–D0 corre-
spond to the segment lines of the MAX7219/MAX7221.
Table 6 shows the one-to-one pairing of each data bit
to the appropriate segment line.
REGISTER DATA
D4
0
0
0
1
REGISTER DATA
D4
X
X
D3
0
0
1
1
D3
X
X
D2
0
0
1
1
Decode-Mode Register
D2
D1
X
X
0
0
1
1
Initial Power-Up
D0
0
1
1
1
D1
X
X
CODE
HEX
00
01
0F
FF
D0
0
1
7