xSPI and UARTx muxing?

wejjan
Posts: 1
Joined: Thu Aug 25, 2016 8:28 am

xSPI and UARTx muxing?

Postby wejjan » Thu Aug 25, 2016 8:58 am

Hi Espressif,

In the esp_wroom_32_datasheet, Section 3.5 Peripheral Interface Description (http://espressif.com/sites/default/file ... eet_en.pdf) is it stated that the UART0, UART1, UART2, HSPI and VSPI interfaces can be muxed to any GPIO pins.
Is it true that I have 100 % flexibility to select each interface pin to any GPIO pin or is it any restrictions (e.g. for boot download)?

Thanks / Wejan

WiFive
Posts: 3529
Joined: Tue Dec 01, 2015 7:35 am

Re: xSPI and UARTx muxing?

Postby WiFive » Fri Aug 26, 2016 1:16 am

Check ESP32 Pin List document. It is pretty flexible, but there are some restrictions.

ESP_Angus
Posts: 2344
Joined: Sun May 08, 2016 4:11 am

Re: xSPI and UARTx muxing?

Postby ESP_Angus » Mon Aug 29, 2016 1:08 am

The Technical Reference Manual section 4 goes over the options for pin muxing in details, but the short answer is "yes you can map most peripherals anywhere".

The long answer includes some caveats:
  • For boot download you should use the standard UART0 pins, as the bootloader runs from ROM and can't choose different pins at boot time.
  • For high speed SPI (ie SPI flash access) you should also use the default pins.
Other than this (other UARTs, secondary SPI peripherals, etc.) you can use the GPIO Matrix (see Technical Reference seciton 4) to map them anywhere.

KevinA
Posts: 14
Joined: Tue Sep 20, 2016 3:09 pm

Re: xSPI and UARTx muxing?

Postby KevinA » Sun Oct 02, 2016 8:31 pm

ESP_Angus wrote:The Technical Reference Manual section 4 goes over the options for pin muxing in details, but the short answer is "yes you can map most peripherals anywhere".
Is there any documentation with example of:
UART1 - TX, RX, RTS, CTS pins being assigned to GPIO MUX, DMA setup, Interrupts setup and enabled?
Thanks

ESP_Angus
Posts: 2344
Joined: Sun May 08, 2016 4:11 am

Re: xSPI and UARTx muxing?

Postby ESP_Angus » Mon Oct 03, 2016 11:56 pm

There isn't an example of any configuration this comprehensive yet, but we're working on providing full examples & driver APIs for these kinds of configurations.

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