From 1c8e8805d82db1081c3abd2dbd32aada19fafe2c Mon Sep 17 00:00:00 2001
From: Nero <41307858+nero@users.noreply.github.com>
Date: Tue, 31 Dec 2019 23:09:11 +0000
Subject: [PATCH] wip sram driver

---
 drivers/sram.c | 32 ++++++++++++++++++++++++++++++++
 drivers/sram.h |  6 ++++++
 2 files changed, 38 insertions(+)
 create mode 100644 drivers/sram.c
 create mode 100644 drivers/sram.h

diff --git a/drivers/sram.c b/drivers/sram.c
new file mode 100644
index 0000000..66fb27f
--- /dev/null
+++ b/drivers/sram.c
@@ -0,0 +1,32 @@
+#include "sram.h"
+
+// 23LCV512 64kB SPI SRAM
+
+uint8_t sram_status() {
+  uint8_t v;
+  PORTB &= ~(1 << 2);
+  spi_transfer(0x05);
+  v = spi_transfer(0x00);
+  PORTB |= (1 << 2);
+  return v;
+}
+
+uint8_t sram_read(uint16_t addr) {
+  uint8_t v;
+  PORTB &= ~(1 << 2);
+  spi_transfer(0x03);
+  spi_transfer(addr & 0xFF);
+  spi_transfer(addr > 8);
+  v = spi_transfer(0x00);
+  PORTB |= (1 << 2);
+  return v;
+}
+
+void sram_write(uint16_t addr, uint8_t v) {
+  PORTB &= ~(1 << 2);
+  spi_transfer(0x02);
+  spi_transfer(addr & 0xFF);
+  spi_transfer(addr > 8);
+  spi_transfer(v);
+  PORTB |= (1 << 2);
+}
diff --git a/drivers/sram.h b/drivers/sram.h
new file mode 100644
index 0000000..d3150a2
--- /dev/null
+++ b/drivers/sram.h
@@ -0,0 +1,6 @@
+#include <stdint.h>
+#include <avr/io.h>
+
+uint8_t sram_status();
+uint8_t sram_read(uint16_t addr);
+void sram_write(uint16_t addr, uint8_t v);