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

[Altera_Forum]

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!

[Altera_Forum]

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!