Rainbow Electronics MAX6959 - Manual (Page 12)

MAX6958/MAX6959
Configuration Register
Use the configuration register to enter and exit shut-
down, check device type, and globally clear the digit
data (Tables 10–13). The S bit selects shutdown or nor-
mal operation (read/write). The D bit reports whether
the device is a MAX6958 or a MAX6959 (read only).
The R bit clears all the digit and segment data (data is
not stored-transient bit)
Scan-Limit Register
The scan-limit register sets the number of digits dis-
played, from one to four (Table 14). A bicolor digit is
connected as two monocolor digits. The scan-limit reg-
ister also limits the number of keys that can be
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).
Intensity Register
An internal pulse-width modulator controlled by the
intensity register provides digital control of display
brightness. The modulator scales the average segment
current in 63 steps from a maximum of 63/64 down to
1/64 of the 23mA peak current. The minimum interdigit
blanking time is set to 1/64 of a cycle (Figure 11 and
Table 15).
2-Wire Interfaced, 3V to 5.5V, 4-Digit,
9-Segment LED Display Drivers with Keyscan
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REGISTER DATA
MODE
ADDRESS
CODE (HEX) D7 D6 D5 D4 D3 D2 D1 D0
Configuration register 0x04 X X R X X X D S
Table 10. Configuration Register Format
REGISTER DATA
MODE
ADDRESS
CODE (HEX) D7 D6 D5 D4 D3 D2 D1 D0
Shutdown mode 0x04 X X R X X X D 0
Normal operation 0x04 X X R X X X D 1
Table 11. Shutdown Control (S Data Bit D0) Format
REGISTER DATA
MODE
ADDRESS
CODE (HEX) D7 D6 D5 D4 D3 D2 D1 D0
MAX6958 0x04 X X R X X X 0 S
MAX6959 0x04 X X R X X X 1 S
Table 12. Device Readback (D Data Bit D1) Format
REGISTER DATA
MODE
ADDRESS
CODE (HEX) D7 D6 D5 D4 D3 D2 D1 D0
Digit and segment data are unaffected 0x04 X X 0 X X X D S
Digit and segment data are cleared 0x04 X X 1 X X X D S
Table 13. Global Clear Digit Data (R Data Bit D5) Format
REGISTER DATA
SCAN LIMIT
ADDRESS
CODE (HEX) D7 D6 D5 D4 D3 D2 D1 D0
HEX
CODE
Display digit 0 and segments 0, 4 0x03 X X X X X X 0 0 0xX0
Display digits 0, 1 and segments 0, 1, 4, 5 0x03 X X X X X X 0 1 0xX1
Display digits 0, 1, 2 and segments 0, 1, 2, 4, 5, 6 0x03 X X X X X X 1 0 0xX2
Display digits 0, 1, 2, 3 and segments 0, 1, 2, 3, 4,
5, 6, 7
0x03 X X X X X X 1 1 0xX3
Table 14. Scan-Limit Register Format