diff --git a/drivers/memory/spiflash.c b/drivers/memory/spiflash.c
new file mode 100644
index 000000000..214610e0a
--- /dev/null
+++ b/drivers/memory/spiflash.c
@@ -0,0 +1,200 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016-2017 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "py/mperrno.h"
+#include "py/mphal.h"
+#include "extmod/machine_spi.h"
+#include "drivers/memory/spiflash.h"
+
+#define CMD_WRITE (0x02)
+#define CMD_READ (0x03)
+#define CMD_WRDI (0x04)
+#define CMD_RDSR (0x05)
+#define CMD_WREN (0x06)
+#define CMD_SEC_ERASE (0x20)
+#define WAIT_SR_TIMEOUT (1000000)
+
+#define PAGE_SIZE (256) // maximum bytes we can write in one SPI transfer
+#define SECTOR_SIZE (4096) // size of erase sector
+
+// Note: this code is not reentrant with this shared buffer
+STATIC uint8_t buf[SECTOR_SIZE];
+
+void mp_spiflash_init(mp_spiflash_t *self) {
+    mp_hal_pin_write(self->cs, 1);
+    mp_hal_pin_output(self->cs);
+    mp_hal_pin_write(self->spi.sck, 0);
+    mp_hal_pin_output(self->spi.sck);
+    mp_hal_pin_output(self->spi.mosi);
+    mp_hal_pin_input(self->spi.miso);
+}
+
+STATIC void mp_spiflash_acquire_bus(mp_spiflash_t *self) {
+    // can be used for actions needed to acquire bus
+    (void)self;
+}
+
+STATIC void mp_spiflash_release_bus(mp_spiflash_t *self) {
+    // can be used for actions needed to release bus
+    (void)self;
+}
+
+STATIC void mp_spiflash_transfer(mp_spiflash_t *self, size_t len, const uint8_t *src, uint8_t *dest) {
+    mp_machine_soft_spi_transfer(&self->spi.base, len, src, dest);
+}
+
+STATIC int mp_spiflash_wait_sr(mp_spiflash_t *self, uint8_t mask, uint8_t val, uint32_t timeout) {
+    uint8_t cmd[1] = {CMD_RDSR};
+    mp_hal_pin_write(self->cs, 0);
+    mp_spiflash_transfer(self, 1, cmd, NULL);
+    for (; timeout; --timeout) {
+        mp_spiflash_transfer(self, 1, cmd, cmd);
+        if ((cmd[0] & mask) == val) {
+            break;
+        }
+    }
+    mp_hal_pin_write(self->cs, 1);
+    if ((cmd[0] & mask) == val) {
+        return 0; // success
+    } else if (timeout == 0) {
+        return -MP_ETIMEDOUT;
+    } else {
+        return -MP_EIO;
+    }
+}
+
+STATIC int mp_spiflash_wait_wel1(mp_spiflash_t *self) {
+    return mp_spiflash_wait_sr(self, 2, 2, WAIT_SR_TIMEOUT);
+}
+
+STATIC int mp_spiflash_wait_wip0(mp_spiflash_t *self) {
+    return mp_spiflash_wait_sr(self, 1, 0, WAIT_SR_TIMEOUT);
+}
+
+STATIC void mp_spiflash_write_cmd(mp_spiflash_t *self, uint8_t cmd) {
+    mp_hal_pin_write(self->cs, 0);
+    mp_spiflash_transfer(self, 1, &cmd, NULL);
+    mp_hal_pin_write(self->cs, 1);
+}
+
+STATIC int mp_spiflash_erase_sector(mp_spiflash_t *self, uint32_t addr) {
+    // enable writes
+    mp_spiflash_write_cmd(self, CMD_WREN);
+
+    // wait WEL=1
+    int ret = mp_spiflash_wait_wel1(self);
+    if (ret != 0) {
+        return ret;
+    }
+
+    // erase the sector
+    mp_hal_pin_write(self->cs, 0);
+    uint8_t cmd[4] = {CMD_SEC_ERASE, addr >> 16, addr >> 8, addr};
+    mp_spiflash_transfer(self, 4, cmd, NULL);
+    mp_hal_pin_write(self->cs, 1);
+
+    // wait WIP=0
+    return mp_spiflash_wait_wip0(self);
+}
+
+STATIC int mp_spiflash_write_page(mp_spiflash_t *self, uint32_t addr, const uint8_t *src) {
+    // enable writes
+    mp_spiflash_write_cmd(self, CMD_WREN);
+
+    // wait WEL=1
+    int ret = mp_spiflash_wait_wel1(self);
+    if (ret != 0) {
+        return ret;
+    }
+
+    // write the page
+    mp_hal_pin_write(self->cs, 0);
+    uint8_t cmd[4] = {CMD_WRITE, addr >> 16, addr >> 8, addr};
+    mp_spiflash_transfer(self, 4, cmd, NULL);
+    mp_spiflash_transfer(self, PAGE_SIZE, src, NULL);
+    mp_hal_pin_write(self->cs, 1);
+
+    // wait WIP=0
+    return mp_spiflash_wait_wip0(self);
+}
+
+void mp_spiflash_read(mp_spiflash_t *self, uint32_t addr, size_t len, uint8_t *dest) {
+    mp_spiflash_acquire_bus(self);
+    uint8_t cmd[4] = {CMD_READ, addr >> 16, addr >> 8, addr};
+    mp_hal_pin_write(self->cs, 0);
+    mp_spiflash_transfer(self, 4, cmd, NULL);
+    mp_spiflash_transfer(self, len, dest, dest);
+    mp_hal_pin_write(self->cs, 1);
+    mp_spiflash_release_bus(self);
+}
+
+int mp_spiflash_write(mp_spiflash_t *self, uint32_t addr, size_t len, const uint8_t *src) {
+    // TODO optimise so we don't need to erase multiple times for successive writes to a sector
+
+    // align to 4096 sector
+    uint32_t offset = addr & 0xfff;
+    addr = (addr >> 12) << 12;
+
+    // restriction for now, so we don't need to erase multiple pages
+    if (offset + len > sizeof(buf)) {
+        printf("mp_spiflash_write: len is too large\n");
+        return -MP_EIO;
+    }
+
+    mp_spiflash_acquire_bus(self);
+
+    // read sector
+    uint8_t cmd[4] = {CMD_READ, addr >> 16, addr >> 8, addr};
+    mp_hal_pin_write(self->cs, 0);
+    mp_spiflash_transfer(self, 4, cmd, NULL);
+    mp_spiflash_transfer(self, SECTOR_SIZE, buf, buf);
+    mp_hal_pin_write(self->cs, 1);
+
+    // erase sector
+    int ret = mp_spiflash_erase_sector(self, addr);
+    if (ret != 0) {
+        mp_spiflash_release_bus(self);
+        return ret;
+    }
+
+    // copy new block into buffer
+    memcpy(buf + offset, src, len);
+
+    // write sector in pages of 256 bytes
+    for (int i = 0; i < SECTOR_SIZE; i += 256) {
+        ret = mp_spiflash_write_page(self, addr + i, buf + i);
+        if (ret != 0) {
+            mp_spiflash_release_bus(self);
+            return ret;
+        }
+    }
+
+    mp_spiflash_release_bus(self);
+    return 0; // success
+}
diff --git a/drivers/memory/spiflash.h b/drivers/memory/spiflash.h
new file mode 100644
index 000000000..d2e817450
--- /dev/null
+++ b/drivers/memory/spiflash.h
@@ -0,0 +1,42 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_DRIVERS_MEMORY_SPIFLASH_H
+#define MICROPY_INCLUDED_DRIVERS_MEMORY_SPIFLASH_H
+
+#include "extmod/machine_spi.h"
+
+typedef struct _mp_spiflash_t {
+    mp_hal_pin_obj_t cs;
+    // TODO replace with generic SPI object
+    mp_machine_soft_spi_obj_t spi;
+} mp_spiflash_t;
+
+void mp_spiflash_init(mp_spiflash_t *self);
+void mp_spiflash_read(mp_spiflash_t *self, uint32_t addr, size_t len, uint8_t *dest);
+int mp_spiflash_write(mp_spiflash_t *self, uint32_t addr, size_t len, const uint8_t *src);
+
+#endif // MICROPY_INCLUDED_DRIVERS_MEMORY_SPIFLASH_H