Expanding 7i97 Smart Serial Ports using SP491 chip

Oh, thanks Andy!

I didn't know about these tools.

I'll be checking right now!

Hi, Andy! 

With you help I was able to successfully flash the firmware!

I will write down the steps I followed to help other users: 

First I downloaded the .zip and then opened a terminal in the folder containing the .bit files. 

Step 0 – Check if communication is ok
mesaflash --device 7I97 --addr 10.10.10.10 --readhmid 

Step 1 – Flash the firmware you want. I my case it was 7i97_7i74D
mesaflash --device 7I97 --addr 10.10.10.10 --verbose --write 7i97_7i74D.bit 

Step 1 – If you get “Error: BootSector is invalid” repeat the first step adding --fix-boot-block flag
mesaflash --device 7I97 --addr 10.10.10.10 --verbose --fix-boot-block --write 7i97_7i74D.bit 

Step 2 – Reload firmware from flash
mesaflash --device 7I97 --addr 10.10.10.10 --verbose –reload 

Step 3 – Verify if flashing went ok
mesaflash --device 7I97 --addr 10.10.10.10 --verbose --verify 7i97_7i74D.bit 

Step 4 – Check if pin mapping fits what you want
mesaflash --device 7I97 --addr 10.10.10.10 –readhmid 

I hope it is useful for people unfamiliar with mesa cards!

I’ll be posting my progress regarding the circuit with SP491 as soon as I have something working. 

Bruno

Hi, forum! 

Well, I still can’t make my second 7i84 card work. 

I’ve flashed the firmware and now there are several sserial ports available on P1. I decided to use port 7, for this is the only one in expansion port with enable pin available. 

My first doubt is regarding the loadrt line.

I can’t understand how to set it up. This is my current line: 

loadrt hm2_eth board_ip="10.10.10.10" config=" num_encoders=6 num_pwmgens=6 num_stepgens=0 sserial_port_0=00000000" 

In this way I can only see in hal configuration the first 7i84 card, connected to serial port 0. 

How is the right loadrt line to make the sserial port appear? (sserial port 7) 

My second doubt is regarding the wiring between SP491 chip and both boards. I've compiled this table with pin mapping. I also attached a table with nomenclature equivalence. There are 3 different nomenclatures used to name RS-485/422 pins among datasheets. Very confusing.

Tomorrow I’ll post schematics and pictures so it will be easier to understand what I've wired so far. 

Bruno

These are the schematics of the circuit I’ve build. 

I haven’t added any terminating resistor so far! I was willing to test without them. Next step will be to add a 120 ohms resistor between A/B and Z/Y. Is there any other resistor required? I was thinking of something like 1k for Rpu and Rpd (according to image attached) but it is just a desperate guess. 

I also attached a picture of the board. 

Can any one guess what is wrong with my approach? 

Thanks in advance! 

Bruno

There was a mistake in the wiring. The atached table is correct now.

I have also added a 120 ohms terminating resistor between A and B. I compared to 7i97 rs485 output and there is 120 ohm resistance only between A and B.

I still won't appear in --sserial (--sserial output atached).

I wonder if PCW has any idea about what could possibly be wrong. I'll attempt to call Mesa and try to talk to someone. Maybe it is just some dumb mistake.

Thanks in advance!

Bruno

Tie /REB low and DE high
(dont use TXEN)

Not on the 7I97_7I74 config, they are all port 0

Great point!

It might be the one mistake!

What about the terminating resistors? I just added one 120 ohms in between A and B. Is it required to add another one in Y Z line?

I will try it out tomorrow again. I hope it works!

Thanks Peter!!