
TB62709NG/FG
2006-06-14
5
DESCRIPTION OF OPERATION
z
Data input (DATA
IN, CLOCK, LOAD)
The data are input serially using the DATA
IN pin. The data input interface consists of a total of three
inputs : DATA
IN, LOAD, and CLOCK.
Binary code stored in the 16
bit shift register offers control modes including duty Control Register Set, Digitset,
Decode Set, and Standby Set,
The data are shifted on the rising edge of the clock, starting from the MSB. Cascade
connecting TB62709NG or
TB62709FG devices provides capability for controlling a larger number of digits.
The serial data in the 16
bit shift register are used as follows : the four bits D
15
(MSB) to D
12
select the IC
operating mode (Table 1), while D11 to D
8
select the register corresponding to the operating mode (Table 2).
Bits D
7
to D
0
(LSB) of the 16
bit shift register are used for detail settings, such as number of digits in use,
character settings in each digit, and light intensity.
The internal registers are loaded on the rising edge of the LOAD signal, which causes loading of data from an
external source into the D
15
(MSB) to D8 bits of the shift register, operating mode and the corresponding
register selection data. On the subsequent falling edge, the detail setting data of D
7
to D0 (LSB) are loaded.
Normally LOAD is Low. After a serial transfer of 16bits, the input of a High
level pulse loads the data.
Note the following caution : Use the D
15
to D
8
setting and the D
7
to D
0
detail data setting as a pair. If only the
D
7
to D
0
data are input without setting D
15
to D
8
an error condition may result, in which the device will not
operate normally. If the current mode is set again by a new signal, the data for D
15
to D
8
must also be re
input.
z
Operating precautions
At power
on or after operation in Clear mode (in initial state), set the IC to Normal mode again. Otherwise, the
IC will not drive the LED.
Operating the IC in Blank mode (all lights off) or in All On mode (all lights lit) does not affect the internal data.
Setting the IC to Normal mode again continues the LED lighting in the state governed by the settings made
immediately before mode change.
Normal mode (not Shut Down, Clear, Blank, or All On mode) continues the operations set in Load Register
mode. In Normal mode, operations are governed by any new settings made in the Load Register, as soon as the
changed setting values are loaded.