ST2226A SiTi, ST2226A Datasheet - Page 10

• Manufacturer Part Number: ST2226A
• Description: PWM-Controlled Constant Current Driver
• Manufacturer: SiTi

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Typical Control Method
1) Command Sequence
as following steps:
diagram. At the same time, DCLK and GCLK remain free running.
3
We used the NOPs (No operation) to wait for the next frame data (at 60Hz) ready.
To manipulate ST2226A, we should properly control the CMD, DIN, DCLK, and GCLK
1.
2.
3.
4.
5.
The process discussed above could be summarized in the following table and timing
ST2226A
Issue command “Shift-in”, and then enter luminance data DIN. Note that ST2226A
starts to shift-in data at the DCLK rising edge next to the edge which latched
Shift-in command.
After data are completely entered, send command “Capture” to save data in
registers.
Send command “Disable”. This step is needed before the “Emitting” command to
keep the chip synchronized.
Issue command “Emitting” or ”Disable”. Note that:
A.
B.
Repeat step 1~4. In the same frame, the luminance data doesn’t have to change,
just repeat step 3~4. Note that the second command “Emitting” will be omitted if
(1024) x T
advance.
點晶科技股份有限公司
點晶科技股份有限公司
SILICON TOUCH TECHNOLOGY INC.
點晶科技股份有限公司
點晶科技股份有限公司
Frame
N-1
ST2226A generates its output in one-shot fashion, i.e. the output after (1024)
x T
There are 2 GCLK latencies between the latched LED Emitting/Disable
command and PWM start/stop. This is shown in Figure 2.
GCLK
GCLK
is always zero.
PWM has not finished, unless the “Disable” command is sent in
Table 1. Example of Command Sequence
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Frame
N
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ST2226A
Frame
N+1