Rust embedded driver for Microchip 23x SRAM/NVSRAM - https://blog.a1w.ca/p/rust-embedded-driver-microchip-23x-sram/

sram.rs

#![no_std]
#![no_main]

use panic_halt as _;

use embedded_graphics::fonts::{Font12x16, Text};
use embedded_graphics::pixelcolor::Rgb565;
use embedded_graphics::prelude::*;
use embedded_graphics::primitives::Rectangle;
use embedded_graphics::{primitive_style, text_style};
use gd32vf103xx_hal::pac;
use gd32vf103xx_hal::prelude::*;
use longan_nano::{lcd, lcd_pins};
use riscv_rt::entry;

use gd32vf103xx_hal::spi::{Spi, MODE_0};
use sram23x::*;

#[entry]
fn main() -> ! {
    let dp = pac::Peripherals::take().unwrap();

    // Configure clocks
    let mut rcu = dp
        .RCU
        .configure()
        .ext_hf_clock(8.mhz())
        .sysclk(108.mhz())
        .freeze();
    let mut afio = dp.AFIO.constrain(&mut rcu);

    let gpioa = dp.GPIOA.split(&mut rcu);
    let gpiob = dp.GPIOB.split(&mut rcu);

    let lcd_pins = lcd_pins!(gpioa, gpiob);
    let mut lcd = lcd::configure(dp.SPI0, lcd_pins, &mut afio, &mut rcu);
    let (width, height) = (lcd.size().width as i32, lcd.size().height as i32);

    // SRAM pins
    let sck = gpiob.pb13.into_alternate_push_pull();
    let miso = gpiob.pb14.into_floating_input();
    let mosi = gpiob.pb15.into_alternate_push_pull();
    let spi1 = Spi::spi1(dp.SPI1, (sck, miso, mosi), MODE_0, 4.mhz(), &mut rcu);
    let hold = gpioa.pa0.into_push_pull_output();
    let cs = gpioa.pa3.into_push_pull_output();

    // Write 'abcdABCD' to SRAM at memory address 0x00
    let mut sram = Sram23x::new(spi1, cs, hold, device_type::M23xv1024).unwrap();
    sram.set_mode(OperatingMode::Sequential as u8).unwrap();
    let mut data: [u8; 8] = ['a' as u8, 'b' as u8, 'c' as u8, 'd' as u8, 65, 66, 67, 68];
    sram.write_sequential(0x00_u32, &mut data).unwrap();

    // Read from SRAM at memory address 0x00
    sram.read_sequential(0x00_u32, &mut data).unwrap();

    // Convert the last 4 bytes into an str, to be displayed on the LCD
    let sramstr = core::str::from_utf8(&data[4..]).unwrap();

    // Clear screen
    Rectangle::new(Point::new(0, 0), Point::new(width - 1, height - 1))
        .into_styled(primitive_style!(fill_color = Rgb565::BLACK))
        .draw(&mut lcd)
        .unwrap();

    let style = text_style!(font=Font12x16, text_color=Rgb565::YELLOW, background_color=Rgb565::BLACK);

    // Create a text at position (20, 30) and draw it using style defined above
    Text::new(&sramstr, Point::new(5, 5))
        .into_styled(style)
        .draw(&mut lcd)
        .unwrap();

    loop {}
}

Add this file to longan nano examples/sram.rs to build and flash this sram firmware.

Build with cargo build --example sram --features=lcd --release.