點晶科技股份有限公司
點晶科技股份有限公司
點晶科技股份有限公司
點晶科技股份有限公司
SILICON TOUCH TECHNOLOGY INC.
ST2226A
ST2226A
Version
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:
:
:A.010
Page
:
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:9
Typical Control Method
1) Command Sequence
To manipulate ST2226A, we should properly control the CMD, DIN, DCLK, and GCLK
as following steps:
1.
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.
2.
After data are completely entered, send command “Capture” to save data in
registers.
3.
Send command “Disable”. This step is needed before the “Emitting” command to
keep the chip synchronized.
4.
Issue command “Emitting” or ”Disable”. Note that:
A. ST2226A generates its output in one-shot fashion, i.e. the output after (1024)
x TGCLK is always zero.
B. There are 2 GCLK latencies between the latched LED Emitting/Disable
command and PWM start/stop. This is shown in Figure 2.
5.
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 TGCLK PWM has not finished, unless the “Disable” command is sent in
advance.
The process discussed above could be summarized in the following table and timing
diagram. At the same time, DCLK and GCLK remain free running.
Table 1. Example of Command Sequence
Frame
N-1
Frame
N
Frame
N+1
3 We used the NOPs (No operation) to wait for the next frame data (at 60Hz) ready.