Forum Discussion
New ContributorI2C connecting
Regular ContributorHi,
Atlas SoC is using the Cyclone V SoC, you may want to refer here for the Mapping HPS IP Peripheral Signals to the FPGA Interface;
https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/an/an706.pdf
It might help you answer your question.
Regards.
New ContributorHi el.ign,
Thanks for you reply. I see that we can route them to FPGA domain. But I also want to know if can we access directly HPS pins without going to FPGA? As I check the schematic of Atlas-SoC board, the I2C1 is connect to LTC header while I2C0 is connected to Accelerometer and no way to access I2C0 externally. That's why I try to access I2C1 by modifying it in Qsys and connect it with jumper on LTC header.
Can I do it as I said? Do I miss something or do I understand things in a wrong way? Or else, I will try to route it to FPGA at the end but I would like to if there is any others ways ( I'm learning ).
By the way, thank you for the answer Mr. el.ign. You have answered almost every questions I made and I really appreciate that.
- EBERLAZARE_I_Intel
Hi,
You mention about the Intel pinout file, can you share to me which is it?
I'm pretty sure according to the Atlas-SoC user manual the HPS I2C0 for SCL and SDA are as C18 and A19 respectively. Have you tried to assign this before you changing them to C19 and B16?
- DChau5
Hi,
Here is the pinout file I use:
https://www.intel.com/content/dam/altera-www/global/en_US/pdfs/literature/dp/cyclone-v/5csema4.pdf
Now I'm trying to use I2C1, this is in my Pin Planner:
According to the provided schematic from manufacturer, I use I2C1 because it is out to LTC header and from there I can connect it with jumper:
Those pins in circle are I2C1_SDA and I2C1_SCL on LTC header:
And for your question, I tried with C18 and A19 then I found out that they are connected to Accelerometer and I don't think I can connect to external slave device using jumper. Therefore, I changed to I2C1 because, yeah, it's connected to LTC header.
- DChau5
Ok, after making above description, I think I realize that I made dumb things. I will try to figure out it first and comeback.
My apology.
- DChau5
Hi el.ign,
Yesterday, I found that I did not assign the pins properly. I went back to my tcl script and assigned those I2C1 pins. Here is what I have:
I have compiled it and programmed FPGA independently in Quartus. Then went to EDS-SoC to run the debug. However, still no result. I am not sure where I did something wrong.
Here is my application code:
#include <stdio.h> #include <stdlib.h> #include <stdbool.h> #include <socal/socal.h> #include <time.h> #include <math.h> #include "alt_i2c.h" #define mcp23008 (0x40) int main(){ ALT_I2C_DEV_t I2C1; ALT_I2C_MASTER_CONFIG_t *cfg; //==============================i2c init ==================== status = alt_i2c_init(ALT_I2C_I2C1,&I2C0); // init the i2c status = alt_i2c_enable(&I2C0); status = alt_i2c_master_config_speed_get(&I2C0, cfg, &speed); printf("INFO: Current I2C speed = %d Hz.\n", (int)speed); set_cfg(&I2C0,cfg);// set up the config for master as desire status = alt_i2c_master_config_speed_get(&I2C0, cfg, &speed); printf("INFO: Current I2C speed = %d Hz.\n", (int)speed); status = alt_i2c_op_mode_set(&I2C0,ALT_I2C_MODE_MASTER); // set it to be a master status = alt_i2c_master_config_set(&I2C0,cfg); // pass the config to i2c instance status = alt_i2c_sda_hold_time_set(&I2C0,3); status = alt_i2c_master_target_set(&I2C0,mcp23008); while (1) { status = alt_i2c_master_transmit(&I2C1,10,1,ALT_E_FALSE,ALT_E_TRUE); } return 0; }In the while loop, I just simply send some random data so I can see the transmission on I2C bus by oscilloscope.
