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faq

This commit is contained in:
olikraus 2018-01-04 14:20:37 +01:00
parent c10f5011f7
commit 0f5d758be6
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doc/faq.txt
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@ -196,19 +196,15 @@ Use the Makefile in this directory to create a Linux binary.
Q: How can I use multiple SPI Displays?
A: For each additional display, separate CS (Chip select) and RST (Reset) lines are required.
```C++
// Setup display1 and display2
U8G2_SSD1306_128X64_NONAME_F_4W_SW_SPI display1(U8G2_R0, /*CLK*/ 18, /*MOSI*/ 23, /*CS*/ 16,
/*DC*/ 17, /*RS*/ 4);
U8G2_SSD1306_128X64_NONAME_F_4W_SW_SPI display2(U8G2_R0, /*CLK*/ 18, /*MOSI*/ 23, /*CS*/ 15,
/*DC*/ 17, /*RS*/ 4);
```
U8G2_SSD1306_128X64_NONAME_F_4W_SW_SPI display1(U8G2_R0, /*CLK*/ 18, /*MOSI*/ 23, /*CS*/ 16,/*DC*/ 17, /*RS*/ 4);
U8G2_SSD1306_128X64_NONAME_F_4W_SW_SPI display2(U8G2_R0, /*CLK*/ 18, /*MOSI*/ 23, /*CS*/ 15,/*DC*/ 17, /*RS*/ 4);
Ensure that the buffer is sent after printing with each display as follows.
```C++
display1.begin();
display2.begin();
...
display1.setCursor(64, 32);
display1.print("DISPLAY 1");
display1.sendBuffer();
@ -216,5 +212,14 @@ Ensure that the buffer is sent after printing with each display as follows.
display2.setCursor(64, 32);
display2.print("DISPLAY 2");
display2.sendBuffer();
```
Q: How can I send individual/special commands to my display.
A: The sequence is: Start transfer, send data and args, close transfer. Note that
this is not portable, because these commands are specific to the display controller.
The following C++/Arduino code will send one command with one argument to the
display:
u8x8_cad_StartTransfer(u8g2.GetU8x8());
u8x8_cad_SendCmd( u8g2.GetU8x8(), <display command>);
u8x8_cad_SendArg( u8g2.GetU8x8(), <display-command-arg>);
u8x8_cad_EndTransfer(u8g2.GetU8x8());