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Technical Details

Layout

  1. Newracom™ NRC7292 WiFi HaLow™ SoC (IEEE 802.11ah draft 8.0 compliant)
  2. Qorvo™ RFFM6901 front-end
  3. IPEX/U.FL antenna connector
  4. Switch for NRC7292 mode selection
  5. 4-pin UART header (2.54 mm pitch)
  6. Raspberry Pi™ HAT form factor with 40-pin GPIO connector
  7. 3× LEDs

Block diagram

Dimension

Pinout

General

Pin Number Pin Name Description
1,17 3.3V Reserved for future use indesigns based on 3.3 V power supply.
(current module design is based on 5V power supply)
2,4 5V 5V DC power
6,9,14,20,25,30,34,39 GND Ground
11,12,13,15,16,18,26,31,32,35,36,37,38,40 NC No connection

SPI

Pin Number Pin Name Description
19 SDI SPI data input
21 SDO SPI data output
23 SCK SPI clock
24 CS SPI chip select

Note

NRC7292 only supports mode SPI_MODE_0(CPOL 0, CPAH 0). For more information, please go to the official document: UG-7292-002-Host driver porting.pdf

I²C

Pin Number Pin Name Description
3 SDA I²C data
5 SCL I²C clock
27 SDA(HAT ID) I²C data, for PiHAT ID EEPROM
28 SCL(HAT ID) I²C clock, for PiHAT ID EEPROM

Note

The SDA(HAT ID) and SCL(HAT ID) are dedicated pins for PiHAT's ID EEPROM usage. For more details, please go to the Raspberry Pi's document here: ADD-ON BOARDS AND HATs

Note

This ID EEPROM contains a machine-readable description of the HAT hardware in a form that allows the Pi to automatically configure the GPIOs and load appropriate device drivers. Ref: https://pihat.readthedocs.io/en/latest/

UART

Pin Number Pin Name Description
8 RX2 NRC7292's UART2 RX (See UARTs)
10 TX2 NRC7292's UART2 TX (See UARTs)

Others

Pin Number Pin Name Description
7 RST System reset (Preservered circuit, disable for now). PM_RESET is triggered by reset button for now
22 VDD FEM CTRL Control RF frontend power.
If VDD_FEM_CTRL=0, VDD_FEM=3.3V
If VDD_FEM_CTRL=1, VDD_FEM=4V
29 INT Interrupt, for NRC7292's SPI_EIRQ
33 UART SEL GPIO for switching UART ports. (See UARTs)
(NOTE: since R0B)

Note

In the 1.3 Hardware components(page 8) section of document UG-7292-002-Host driver porting.pdf describes hardware GPIOs and pinout mappings.

LEDs

Label name Description
POWER When the module is powered up, this GREEN led turns on
TX ORANGE led, controlled by GPIO
RX RED led, controlled by GPIO

GPIOs

NRC7292 GPIO # Default Pin Number Description
02 UART2 RTS , connected to LED:TX
03 UART2 CTS , connected to LED:RX
16 5 I²C SCL
17 3 I²C SDA
25 IN, HIGH 22 VDD_FEM_CTRL
30 SDA , connect to an onboard temp sensor IC(label:U6)
31 SCL , connect to an onboard temp sensor IC(label:U6)

Note

Known NRC7292 GPIO's range is [0..31]

UARTs

NRC7292 has 4 UART channels. We have two available in this PiHAT device.

NRC7292 defines AHPI7292S Description Position
UART0 Undefined
UART1 Undefined
UART2 RX2, TX2 available for STANDALONE MODE
UART3 4-pin UART header for DOWNLOAD MODE use

UART port switching with "UART SEL" GPIO

The TX,RX in PiHAT pinouts and 4-pin UART header can be swapped in specific conditions below:

Mode switch state GPIO of UART SEL
Host mode OUT, HIGH(1)
Standalone mode OUT, HIGH(1)
Download mode OUT, HIGH(1) or IN

This UART port switching mechanism make it possible to reflash firmware without manual 4-pin UART header wirings.

Revisions

Comparsion:

R0A R0B R0C
Mode switch DIP switch Slide switch Slide switch
RF connector IPEX (CN1) SMA (CN1)
IPEX (CN2)
IPEX (CN1)
SMA (CN2)
UART SEL undefined defined defined
UART3 label TX3,RX3 TX3,RX3 TX,RX

Differences:

Before After Notes
R0A
R0B
RF connector change position.
Mode swith change from DIP switch to slide switch.
Add reset button
R0B
R0C
RF connector change position.
TX3,RX3 change to TX,RX

Modes

NRC7292 has 3 modes: HOST MODE, STANDALONE MODE, and DOWNLOAD MODE

HOST MODE

In this mode, the target device will act as a SPI slave device. The host device (ex: Raspberry Pi) need a proper driver to bring it up and controll it.

STANDALONE MODE

In this mode, the target device doesn't need external drivers. It will be up and running by itself while power on. Since it's self-running device, it required a built-in firmware to define its routines and behaviors.

Other devices can talk to this device throungh a UART interface, send commands and receives data with it.

DOWNLOAD MODE

This mode is for developers to upload firmware to this target device, so that it can be properly running in STANDALONE MODE.

There is an official document introduce how to utilize this mode, please see reference below:

Note

For more details, please read the upstream document UG-7292-004-Standalone SDK.pdf , page 18, chapter of "3 How to download compiled binaries"

How to switch modes

For revision R0A:

The R0A revision use a DIP switch to switch modes:

Mode Mode_03 ... Mode_00
Host mode [0,0,0,1]
Standalone mode [0,1,0,0]
Download mode [0,0,1,1]

For revision R0B, R0C:

New revisions are using slide switches: