Bit error when in AR9331

[YYYaoSir]

I compile and install this kmod in AR9331(400MHZ Mips Soc). It works. I can use the ttySOFT0 to transmit and recieve. But it always encounters some bit error. I modified some of the code, now it works well.

1: Change the RX trigger from "IRQF_TRIGGER_FALLING" to "IRQF_TRIGGER_LOW".
2: In handle_rx_start(), after start the timer, disable the RX_IRQ
if (rx_bit_index == -1) { hrtimer_start(&timer_rx, ktime_set(0, 0), HRTIMER_MODE_REL); } disable_irq_nosync(gpio_to_irq(gpio_rx)); return (irq_handler_t) IRQ_HANDLED;
3: After has recieved a byte, enable the RX_IRQ.
receive_character(character); rx_bit_index = -1; enable_irq(gpio_to_irq(gpio_rx));

It reduce the bit error when RX receive bits significantly. I haven't test it in Raspberry pi. You can test it. Maybe it will improve the baud rate.

[adrianomarto]

Hi YYYaoSir,

Thanks for the suggestion. I will definitively try it.

Kind regards,

Adriano.

[adrianomarto]

Hi @YYYaoSir,

@ulde has provided a different solution for what seems to be the same problem you are experiencing. Would you mind trying his modification and verifying if it reduces the bit errors?

See:
#5
Kind regards,

Adriano.