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i2s lcd mode data out idle state level
Posted: Fri Oct 25, 2019 11:21 pm
by Baldhead
Hi,
I would like to know what are the idle state level of i2s data output, after data send out ?
Example: 8 data outputs.
All output pins are all at high logic level or all output pins at low logic level ?
Or the output pins store last byte transmitted state ?
Or the output pins are all in tristate(high impedance) ?
Thank's.
Re: i2s lcd mode data out idle state level
Posted: Tue Oct 29, 2019 10:34 pm
by Baldhead
no one ?
Re: i2s lcd mode data out idle state level
Posted: Wed Nov 06, 2019 4:37 pm
by Baldhead
??????
Re: i2s lcd mode data out idle state level
Posted: Sun Nov 17, 2019 2:51 am
by Baldhead
By my tests the output goes back to idle state after a little time.
Re: i2s lcd mode data out idle state level
Posted: Thu Nov 28, 2019 8:41 pm
by Baldhead
Hi,
With 10 MHz using APLL_CLK the data bus stay active(i am testing with logic level = 1) for 500 ns( 5 clock period ) after last clock(ws pin) rising edge, and after this 500ns time the i2s module stay in idle state and the port stay in tristate i think(even though the data bus gets 0 volts, maybe i2s force the data bus to zero volts).
Re: i2s lcd mode data out idle state level
Posted: Fri Nov 29, 2019 6:16 am
by ESP_houwenxiang
Hi, Baldhead
the data out idle state level is 0, when the data, when the data transmission is complete and reset tx mode(tx_reset = 1; tx_reset = 0;), the data line will return to 0.
Re: i2s lcd mode data out idle state level
Posted: Fri Nov 29, 2019 7:05 pm
by Baldhead
Hi,
I put a delay before i call the "instruction" "tx_reset( )" to take a test like:
"send Data";
while ( ! ( I2SX.state.tx_idle ) );
vTaskDelay(1/portTICK_PERIOD_MS); // 1 milisecond.
tx_reset( );
Code: Select all
static void tx_reset( )
{
I2SX.conf.tx_reset = 1; // Set this bit to reset the transmitter. (R/W)
I2SX.conf.tx_reset = 0;
}
The i2s parallel output now it took 90 us( 90 clock periods with 10 MHz) to enter in "idle state" ( timeout maybe ? ).
The time that i2s bus stay active after last rising edge of the clock are configurable ?
If time could be "infinite" i could test with leds on parallel port to verify that data is being sent correctly in the absence of a logical analyzer.
Thank's.