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Cyclone V LCD / I2C (baremetal) sample for Altera's SoC DevKit

Altera_Forum
Honored Contributor II
1,355 Views

Hi community, 

 

anybody out there ever programmed the Newhaven LCD on the Altera SoC (Cyclone V) DevKit baremetal

 

If I didn't miss something Altera's hwlib doesn't provide support for I2C (not to mention support for the LCD). 

As I'm not a linux expert the linux i2c driver isn't very helpfull either. 

If someone could give me a hint where to look for a starting point, that would be really great. 

 

 

Thanks a lot for your support!
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1 Reply
Altera_Forum
Honored Contributor II
222 Views

Hi, 

 

I want to give you some hints to get it running. 

it's not very difficult to get it running on a baremetal system. You can still use the hwlib. 

There is a headerfile called alt_i2c.h. This file contains a lot of definitions, needed to implement an i2c driver for your application. 

 

To write something to the LCD you have to do the following steps: 

 

first step: you need to write an init-function for the i2c interface. here you have to do the following steps: 

 

 

  1. Disable the i2c controller by clearing the enabled bit in the alt_i2c_en register 

  2. set the controller to master mode (register alt_i2c_con_mst_mod

  3. set the speed to standard (the newheaven display only supports 100khz clock rate) (register alt_i2c_con_speed

  4. enable the i2c controller (set enabled bit in the alt_i2c_en register) 

 

 

 

second step: address the slave 

 

  1. write the address of the slave to the alt_i2c_tar register 

 

 

 

third step: the write function: 

 

  1. to send data you have to set the ALT_i2c_data_cmd_cmd Register to WRITE 

  2. write the data to the alt_i2c_data_cmd_dat Register 

 

 

 

Now data will be send on the I2C. If you want to implement a full driver you can also check the status register etc. when you send some data... 

 

Some hints for the newheaven LCD: 

 

 

  • Slave address is 0x28 (and not 0x50) 

  • between the commands you send, you need a delay (normally 100µs). 

  • A full list of special commands for the display you can find in the newheaven specification. (Download it from the newheaven website. The LCD is the NHD-0216K3Z) 

 

 

 

I hope it helps you a bit. 

 

Regards!
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