WINC1500 MCU Interface
InterfaceWithPictures.png

There are four main signals that are needed to interface the ATWINC15x0-MR210xB module with the host microcontroller: CHIP_EN, RESET, SPI, and IRQN. The signals that control the WINC1500's boot up sequence are the CHIP_EN and RESET. CHIP_EN is used to power the WINC1500; whenever the CHIP_EN pin is HIGH, the WINC1500 will be powered up and the oscillators will be initialized and stabilized. After the time needed for the oscillator to settle (5 ms as per the datasheet), the RESET pin needs to be set HIGH, which causes the WINC1500 to boot up.

Communication with the host takes place through SPI. The maximum frequency that the WINC1500 supports is 48 MHz. The WINC1500 normally operates as a slave which means that the host is responsible for feeding the SPI clock signal to the WINC1500.

The last signal needed is the interrupt signal, IRQN. Whenever there is a completion of any event, the WINC1500 will raise the interrupt flag to let the host MCU know that the event is complete and that the host can now read some data from the WINC1500.

CHIP_EN, RESET, and IRQN are normally connected to GPIO. IRQN is an external interrupt so you can either use the GPIO interrupt feature or a dedicated external interrupt pin if there is one available on your host MCU.

SPI Interface

The ATWINC15x0-MR210xB has a Serial Peripheral Interface (SPI) that operates as an SPI slave. The SPI interface can be used for control and for serial I/O of 802.11 data. The SPI is a full-duplex slave-synchronous serial interface that is available immediately following reset when pin 10 (SPI_CFG) is tied to VDDIO. The SPI pins are mapped as shown in the following table.
Pin Number Name Description Programmable Pull Up Resistor
10 CFG: Must be tied to VDDIO Tie to VDDIO through a 1 MΩ resistor to enable the SPI interface No
16 SSN: Active-Low Slave Select SPI Slave Select. Active-Low Yes
15 MOSI(RXD): Serial Data Receive SPI MOSI (Master Out, Slave In) pin Yes
18 SCK: Serial Clock SPI Clock Yes
17 MISO(TXD): Serial Data Transmit SPI MISO (Master In, Slave Out) pin Yes

The internal programmable pull-up resistors on the SPI SSN, MOSI, MISO, and SCK pins of the ATWINC15x0-MR210xB should be programmed to be disabled. Otherwise, if any of the SPI pins are driven to a low level while the ATWINC15x0-MR210xB is in the low power sleep state, the current will flow from the VDDIO supply through the pull-up resistors, increasing the current consumption of the module.

Pull-up configuration is enabled via usage of the m2m_periph_pullup_xxx WINC1500 driver APIs in the WINC1500 Code Examples in Atmel Studio.

SPI Application Schematic

spi-application-schematic.png

Other Signal Descriptions

  • WAKE
    • Used along with the UART Interface to implement power down functions. Not currently implemented in WINC1500 firmware.
  • UART_RXD/UART_TXD
    • Alternate control/data interface (not currently implemented). Current usage: output WINC1500 firmware debug messages.
  • I2C Interface
    • Used for applications that require radio certification or if using chip-down designs. Otherwise, leave unconnected.
  • GPIO_x Pins
    • These pins are configured and used via APIs in the m2m_periph.c Advanced Software Framework (ASF) driver file.

For more information on how to interface with the host microcontroller, refer to Section 7 of the "WINC1500 Datasheet".

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