Datasheet

Scan-Limit Register
The scan-limit register sets how many digits are dis-
played, from 1 to 8. They are displayed in a multiplexed
manner with a typical display scan rate of 800Hz with 8
digits displayed. If fewer digits are displayed, the scan
rate is 8f
OSC
/N, where N is the number of digits
scanned. Since the number of scanned digits affects
the display brightness, the scan-limit register should
not be used to blank portions of the display (such as
leading zero suppression). Table 8 lists the scan-limit
register format.
MAX7219/MAX7221
Serially Interfaced, 8-Digit LED Display Drivers
_______________________________________________________________________________________ 9
Table 7. Intensity Register Format (Address (Hex) = XA)
DUTY CYCLE
MAX7221MAX7219
D6D7 D4 D2D3 D0D5 D1
HEX
CODE
1/16
(min on)
1/32
(min on)
XX XX 00 00 X0
2/163/32 XX XX 00 10 X1
3/165/32 XX XX 00 01 X2
4/167/32 XX XX 00 11 X3
5/169/32 XX XX 10 00 X4
6/1611/32 XX XX 10 10 X5
7/1613/32 XX XX 10 01 X6
X8/1615/32 XX X
X
10 11 X7
9/1617/32 XX X
X
01 00 X8
10/1619/32 XX X
X
01 10 X9
11/1621/32 XX X
X
01 01 XA
12/1623/32 XX X
X
01 11 XB
13/1625/32 XX X
X
11 00 XC
14/1627/32 XX X
X
11 10 XD
15/1629/32 XX X
X
11 01 XE
15/16
(max on)
31/32 XX X 11 11 XF
Table 8. Scan-Limit Register Format (Address (Hex) = XB)
X
XDisplay digit 0 only*
Display digits 0 & 1*
X
X X
D7
SCAN LIMIT
X1
X X0
X
X
X 0
D6 D5
0 1
D4 D3
X
XDisplay digits 0 1 2*
Display digits 0 1 2 3
X
X
X X
0
X3
X
D2
HEX
CODE
X2
0
REGISTER DATA
0
X
X
X
D1 D0
0 1 1
X 0 1 0
X
XDisplay digits 0 1 2 3 4
Display digits 0 1 2 3 4 5
X
X X X5
X X4
X
X
X 1 0 1
X
XDisplay digits 0 1 2 3 4 5 6
Display digits 0 1 2 3 4 5 6 7
X
X
X X
1
X7
X X6
0 0
X
X
X 1 1 1
X 1 1 0
*See Scan-Limit Register section for application.